fix(addon-image): cast buffer line lookups to IBufferLineExt | undefined

Co-authored-by: Daniel Imms <Tyriar@users.noreply.github.com>

.oxlintrc.json

@@ -1,6 +1,7 @@
 {
   "$schema": "./node_modules/oxlint/configuration_schema.json",
   "plugins": [
+    "import",
     "typescript"
   ],
   "categories": {
@@ -104,7 +105,8 @@
     "typescript/no-wrapper-object-types": "error",
     "typescript/prefer-as-const": "error",
     "typescript/prefer-namespace-keyword": "error",
-    "typescript/triple-slash-reference": "error"
+    "typescript/triple-slash-reference": "error",
+    "import/no-cycle": "error"
   },
   "overrides": [
     {

CONTRIBUTING.md

@@ -39,7 +39,7 @@ The preferred way to report bugs or request features is to use
 
 It's pretty common for maintainers of large open source projects to suffer from burnout, especially when needing to triage a large number of incoming issues instead of actually building things. Here are some of the steps we take to try mitigate this:
 
-- Support questions live in [GH discussions](https://github.com/xtermjs/xterm.js/discussions), issues may be transfered there without further comment and core maintainers may or may not participate in discussions.
+- Support questions live in [GH discussions](https://github.com/xtermjs/xterm.js/discussions), issues may be transferred there without further comment and core maintainers may or may not participate in discussions.
 - Issues are strictly for well defined features or bugs that are _actionable_.
 - Sometimes features are out of scope. A common example of this is a niche feature that the pricipal implementation ([VS Code](https://code.visualstudio.com/)) won't leverage and therefore would be difficult to maintain and likely suffer from bitrot. The reporter may not agree with this, but you could always create an addon if that works or maintain your own fork if it comes to that.
 - If a feature does not have a clear way forward or needs more discussion it may be closed ro moved to a discussion.

addons/addon-attach/test/AttachAddon.test.ts

@@ -15,7 +15,7 @@ test.beforeAll(async ({ browser }) => {
 });
 test.afterAll(async () => await ctx.page.close());
 
-test.describe('Search Tests', () => {
+test.describe('AttachAddon', () => {
 
   test.beforeEach(async () => {
     await ctx.proxy.reset();

addons/addon-clipboard/typings/addon-clipboard.d.ts

@@ -82,7 +82,7 @@ declare module '@xterm/addon-clipboard' {
   /**
    * The clipboard provider interface that enables xterm.js to access the browser clipboard.
    *
-   * Note this this clipboard provider does not implement own cut buffers as xterm does,
+   * Note that this clipboard provider does not implement own cut buffers as xterm does,
    * but redirect the selection parameter always to navigator.clipboard.
    */
   export class BrowserClipboardProvider implements IClipboardProvider{

addons/addon-fit/src/FitAddon.ts

@@ -74,14 +74,14 @@ export class FitAddon implements ITerminalAddon, IFitApi {
       : (this._terminal.options.scrollbar?.width ?? ViewportConstants.DEFAULT_SCROLL_BAR_WIDTH));
 
     const parentElementStyle = _getComputedStyle(this._terminal.element.parentElement);
-    const parentElementHeight = parseInt(parentElementStyle.getPropertyValue('height'));
-    const parentElementWidth = Math.max(0, parseInt(parentElementStyle.getPropertyValue('width')));
+    const parentElementHeight = Math.max(0, parseInt(parentElementStyle.getPropertyValue('height'), 10) || 0);
+    const parentElementWidth = Math.max(0, parseInt(parentElementStyle.getPropertyValue('width'), 10) || 0);
     const elementStyle = _getComputedStyle(this._terminal.element);
     const elementPadding = {
-      top: parseInt(elementStyle.getPropertyValue('padding-top')),
-      bottom: parseInt(elementStyle.getPropertyValue('padding-bottom')),
-      right: parseInt(elementStyle.getPropertyValue('padding-right')),
-      left: parseInt(elementStyle.getPropertyValue('padding-left'))
+      top: parseInt(elementStyle.getPropertyValue('padding-top'), 10) || 0,
+      bottom: parseInt(elementStyle.getPropertyValue('padding-bottom'), 10) || 0,
+      right: parseInt(elementStyle.getPropertyValue('padding-right'), 10) || 0,
+      left: parseInt(elementStyle.getPropertyValue('padding-left'), 10) || 0
     };
     const elementPaddingVer = elementPadding.top + elementPadding.bottom;
     const elementPaddingHor = elementPadding.right + elementPadding.left;

addons/addon-image/README.md

@@ -90,7 +90,7 @@ terminal.loadAddon(imageAddon);
   therefore palette animations cannot be used.
 
 - **SIXEL Raster Attributes Handling**  
-  If raster attributes were found in the SIXEL data (level 2), the image will always be truncated to the given height/width extend. We deviate here from the specification on purpose, as it allows several processing optimizations. For level 1 SIXEL data without any raster attributes the image can freely grow in width and height up to the last data byte, which has a much higher processing penalty. In general encoding libraries should not create level 1 data anymore and should not produce pixel information beyond the announced height/width extend. Both is discouraged by the >30 years old specification.
+  If raster attributes were found in the SIXEL data (level 2), the image will always be truncated to the given height/width extent. We deviate here from the specification on purpose, as it allows several processing optimizations. For level 1 SIXEL data without any raster attributes the image can freely grow in width and height up to the last data byte, which has a much higher processing penalty. In general encoding libraries should not create level 1 data anymore and should not produce pixel information beyond the announced height/width extent. Both is discouraged by the >30 years old specification.
 
   Currently the SIXEL implementation of the addon does not take custom pixel sizes into account, a SIXEL pixel will map 1:1 to a screen pixel.
 
@@ -149,9 +149,9 @@ The addon provides the following API endpoints to retrieve raw image data as can
 
 ### Memory Usage
 
-The addon does most image processing in Javascript and therefore can occupy a rather big amount of memory. To get an idea where the memory gets eaten, lets look at the data flow and processing steps:
-- Incomming image data chunk at `term.write` (terminal)  
-  `term.write` might stock up incoming chunks. To circumvent this, you will need proper flow control (see xterm.js docs). Note that with image output it is more likely to run into this issue, as it can create lots of MBs in very short time.
+The addon does most image processing in JavaScript and therefore can occupy a rather big amount of memory. To get an idea where the memory gets eaten, let's look at the data flow and processing steps:
+- Incoming image data chunk at `term.write` (terminal)  
+  `term.write` might stack up incoming chunks. To circumvent this, you will need proper flow control (see xterm.js docs). Note that with image output it is more likely to run into this issue, as it can create lots of MBs in very short time.
 - Sequence Parser (terminal)  
   The parser operates on a buffer containing up to 2^17 codepoints (~0.5 MB).
 - Sequence Handler - Chunk Decoding (addon)  
@@ -177,18 +177,18 @@ const totalActive = storageBytes + decodingBytes;
 ```
 
 Note that browsers have offloading tricks for rarely touched memory segments, esp. `storageBytes` might not directly translate into real memory usage. Usage peaks will happen during active decoding of multiple big images due to the need of 2 full pixel buffers at the same time, which cannot be offloaded. Thus you may want to keep an eye on `pixelLimit` under limited memory conditions.  
-Further note that the formulas above do not respect the Javascript object's overhead. Compared to the raw buffer needs the book keeping by these objects is rather small (<<5%).
+Further note that the formulas above do not respect the JavaScript object's overhead. Compared to the raw buffer needs the bookkeeping by these objects is rather small (<<5%).
 
 _Why should I care about memory usage at all?_  
-Well you don't have to, and it probably will just work fine with the addon defaults. But for bigger integrations, where much more data is held in the Javascript context (like multiple terminals on one page), it is likely to hit the engine's memory limit sooner or later under decoding and/or storage pressure.
+Well you don't have to, and it probably will just work fine with the addon defaults. But for bigger integrations, where much more data is held in the JavaScript context (like multiple terminals on one page), it is likely to hit the engine's memory limit sooner or later under decoding and/or storage pressure.
 
 _How can I adjust the memory usage?_  
 - `pixelLimit`  
-  A constructor setting, thus you would have to anticipate, whether (multiple) terminals in your page gonna do lots of concurrent decoding. Since this is normally not the case and the memory usage is only temporarily peaking, a rather high value should work even with multiple terminals in one page.
+  A constructor setting, thus you would have to anticipate, whether (multiple) terminals in your page gonna do lots of concurrent decoding. Since this is normally not the case and the memory usage only peaks temporarily, a rather high value should work even with multiple terminals in one page.
 - `storageLimit`  
-  A constructor and a runtime setting. In conjunction with `storageUsage` you can do runtime checks and adjust the limit to your needs. If you have to lower the limit below the current usage, images will be removed in FIFO order and may turn into a placeholder in the terminal's scrollback (if `showPlaceholder` is set). When adjusting keep in mind to leave enough room for memory peaking for decoding.
+  A constructor and a runtime setting. In conjunction with `storageUsage` you can do runtime checks and adjust the limit to your needs. If you have to lower the limit below the current usage, images will be removed in FIFO order and may turn into a placeholder in the terminal's scrollback (if `showPlaceholder` is set). When adjusting keep in mind to leave enough room for peak memory use during decoding.
 - `sixelSizeLimit | iipSizeLimit | kittySizeLimit`  
-  Constructor settings. This has only a small impact on peaking memory during decoding. It is meant to avoid processing of overly big or broken image sequences at an earlier phase, thus may stop the invoked decoders from entering memory intensive tasks for potentially invalid data.
+  Constructor settings. This has only a small impact on peak memory during decoding. It is meant to avoid processing of overly big or broken image sequences at an earlier phase, thus may stop the invoked decoders from entering memory intensive tasks for potentially invalid data.
 
 
 ### Terminal Interaction

addons/addon-image/src/IIPHandler.ts

@@ -222,8 +222,8 @@ export class IIPHandler implements IOscHandler, IResetHandler {
 
   private _dim(s: string, total: number, cdim: number): number {
     if (s === 'auto') return 0;
-    if (s.endsWith('%')) return parseInt(s.slice(0, -1)) * total / 100;
-    if (s.endsWith('px')) return parseInt(s.slice(0, -2));
-    return parseInt(s) * cdim;
+    if (s.endsWith('%')) return parseInt(s.slice(0, -1), 10) * total / 100;
+    if (s.endsWith('px')) return parseInt(s.slice(0, -2), 10);
+    return parseInt(s, 10) * cdim;
   }
 }

addons/addon-image/src/ImageStorage.ts

@@ -431,8 +431,8 @@ export class ImageStorage implements IDisposable {
     // because text writes clear the BG flag but leave image tile data intact.
     // This lets top-layer images survive text overwrites (kitty C=1 behavior).
     for (let row = start; row <= end; ++row) {
-      const line = buffer.lines.get(row + buffer.ydisp) as IBufferLineExt;
-      if (!line) return;
+      const line = buffer.lines.get(row + buffer.ydisp) as IBufferLineExt | undefined;
+      if (!line) continue;
       for (let col = 0; col < cols; ++col) {
         let e: IExtendedAttrsImage;
         if (line.getBg(col) & BgFlags.HAS_EXTENDED) {
@@ -513,7 +513,10 @@ export class ImageStorage implements IDisposable {
     const rows = buffer.lines.length;
     const oldCol = this._viewportMetrics.cols - 1;
     for (let row = 0; row < rows; ++row) {
-      const line = buffer.lines.get(row) as IBufferLineExt;
+      const line = buffer.lines.get(row) as IBufferLineExt | undefined;
+      if (!line) {
+        continue;
+      }
       if (line.getBg(oldCol) & BgFlags.HAS_EXTENDED) {
         const e: IExtendedAttrsImage = line._extendedAttrs[oldCol] ?? EMPTY_ATTRS;
         const imageId = e.imageId;
@@ -531,7 +534,7 @@ export class ImageStorage implements IDisposable {
         }
         // expand only if right side is empty (nothing got wrapped from below)
         let hasData = false;
-        for (let rightCol = oldCol + 1; rightCol > metrics.cols; ++rightCol) {
+        for (let rightCol = oldCol + 1; rightCol < metrics.cols; ++rightCol) {
           if (line._data[rightCol * Cell.SIZE + Cell.CONTENT] & Content.HAS_CONTENT_MASK) {
             hasData = true;
             break;

addons/addon-image/src/Types.ts

@@ -9,7 +9,8 @@ import { IDisposable, IMarker, Terminal } from '@xterm/xterm';
 import { Attributes, BgFlags, Content, ExtFlags, UnderlineStyle } from 'common/buffer/Constants';
 import type { AttributeData } from 'common/buffer/AttributeData';
 import type { IParams, IDcsHandler, IOscHandler, IApcHandler, IEscapeSequenceParser } from 'common/parser/Types';
-import type { IBufferLine, IExtendedAttrs, IInputHandler } from 'common/Types';
+import type { IInputHandler } from 'common/Types';
+import type { IBufferLine, IExtendedAttrs } from 'common/buffer/Types';
 import type { ITerminal, ReadonlyColorSet } from 'browser/Types';
 import type { IRenderDimensions } from 'browser/renderer/shared/Types';
 import type { ICoreBrowserService, IRenderService, IThemeService } from 'browser/services/Services';

addons/addon-image/src/kitty/KittyGraphicsTypes.ts

@@ -168,7 +168,7 @@ export function parseKittyCommand(data: string): IKittyCommand {
       cmd.deleteSelector = value;
       continue;
     }
-    const numValue = parseInt(value);
+    const numValue = parseInt(value, 10);
     switch (key) {
       case KittyKey.FORMAT: cmd.format = numValue; break;
       case KittyKey.ID: cmd.id = numValue; break;

addons/addon-ligatures/src/index.ts

@@ -21,7 +21,7 @@ const CACHE_SIZE = 100000;
 
 /**
  * Enable ligature support for the provided Terminal instance. To function
- * properly, this must be called after `open()` is called on the therminal. If
+ * properly, this must be called after `open()` is called on the terminal. If
  * the font currently in use supports ligatures, the terminal will automatically
  * start to render them.
  * @param term Terminal instance from xterm.js

addons/addon-search/src/DecorationManager.test.ts

@@ -0,0 +1,81 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { DecorationManager } from './DecorationManager';
+import { SearchEngine } from './SearchEngine';
+import { SearchLineCache } from './SearchLineCache';
+import { Terminal } from 'browser/public/Terminal';
+import type { ISearchDecorationOptions } from '@xterm/addon-search';
+import type { IDecorationOptions } from '@xterm/xterm';
+import { DisposableStore } from 'common/Lifecycle';
+
+function writeP(terminal: Terminal, data: string): Promise<void> {
+  return new Promise(r => terminal.write(data, r));
+}
+
+describe('DecorationManager', () => {
+  let store: DisposableStore;
+  let terminal: Terminal;
+  let decorationManager: DecorationManager;
+
+  beforeEach(() => {
+    store = new DisposableStore();
+    terminal = store.add(new Terminal({ cols: 10, rows: 5 }));
+    decorationManager = store.add(new DecorationManager(terminal));
+  });
+
+  it('should split highlight decorations for a wrapped match', async () => {
+    await writeP(terminal, '0123456789abcde');
+    const searchEngine = new SearchEngine(terminal, store.add(new SearchLineCache(terminal)));
+    const match = searchEngine.find('9abc', 0, 0);
+    assert.ok(match);
+
+    const decorationOptions: IDecorationOptions[] = [];
+    const registerDecoration = terminal.registerDecoration.bind(terminal);
+    terminal.registerDecoration = (options: IDecorationOptions) => {
+      decorationOptions.push(options);
+      return registerDecoration(options);
+    };
+
+    const options: ISearchDecorationOptions = {
+      matchOverviewRuler: '#ff0000',
+      activeMatchColorOverviewRuler: '#00ff00'
+    };
+    decorationManager.createHighlightDecorations([match], options);
+
+    assert.strictEqual(decorationOptions.length, 2);
+    assert.strictEqual(decorationOptions[0].x, 9);
+    assert.strictEqual(decorationOptions[0].width, 1);
+    assert.strictEqual(decorationOptions[1].x, 0);
+    assert.strictEqual(decorationOptions[1].width, 3);
+
+    const withOverviewRuler = decorationOptions.filter(o => o.overviewRulerOptions !== undefined);
+    assert.strictEqual(withOverviewRuler.length, 2);
+  });
+
+  it('should only add one overview ruler marker per buffer line', async () => {
+    await writeP(terminal, 'abcdefghij');
+    const decorationOptions: IDecorationOptions[] = [];
+    const registerDecoration = terminal.registerDecoration.bind(terminal);
+    terminal.registerDecoration = (options: IDecorationOptions) => {
+      decorationOptions.push(options);
+      return registerDecoration(options);
+    };
+
+    const options: ISearchDecorationOptions = {
+      matchOverviewRuler: '#ff0000',
+      activeMatchColorOverviewRuler: '#00ff00'
+    };
+    decorationManager.createHighlightDecorations([
+      { term: 'a', col: 0, row: 0, size: 1 },
+      { term: 'f', col: 5, row: 0, size: 1 }
+    ], options);
+
+    const withOverviewRuler = decorationOptions.filter(o => o.overviewRulerOptions !== undefined);
+    assert.strictEqual(withOverviewRuler.length, 1);
+    assert.strictEqual(withOverviewRuler[0].x, 0);
+  });
+});

addons/addon-search/src/SearchEngine.ts

@@ -60,7 +60,7 @@ export class SearchEngine {
       this._terminal.clearSelection();
       return undefined;
     }
-    if (startCol > this._terminal.cols) {
+    if (startCol >= this._terminal.cols) {
       throw new Error(`Invalid col: ${startCol} to search in terminal of ${this._terminal.cols} cols`);
     }
 

addons/addon-search/test/SearchAddon.test.ts

@@ -417,7 +417,7 @@ test.describe('Search Tests', () => {
     test.describe('#2444 wrapped line content not being found', () => {
       let fixture: string;
       test.beforeAll(async () => {
-        fixture = (await new Promise<Buffer>(r => readFile(resolve(__dirname, '../fixtures/issue-2444'), (err, data) => r(data)))).toString();
+        fixture = (await new Promise<Buffer>((res, rej) => readFile(resolve(__dirname, '../fixtures/issue-2444'), (err, data) => err ? rej(err) : res(data)))).toString();
         if (process.platform !== 'win32') {
           fixture = fixture.replace(/\n/g, '\n\r');
         }
@@ -501,7 +501,7 @@ test.describe('Search Tests', () => {
         window.search.onDidChangeResults(e => window.calls.push(e));
       `);
       // Move cursor forward 1 time to create a null character, as opposed to regular whitespace
-      await ctx.proxy.write('\\x1b[CHi Hi');
+      await ctx.proxy.write('\x1b[CHi Hi');
       strictEqual(await ctx.page.evaluate(`window.search.findPrevious('h', { decorations: { activeMatchColorOverviewRuler: '#ff0000' } })`), true);
       deepStrictEqual(await ctx.page.evaluate('window.calls'), [
         { resultCount: 2, resultIndex: 1 }

addons/addon-serialize/src/SerializeAddon.ts

@@ -7,7 +7,8 @@
 
 import type { IBuffer, IBufferCell, IBufferRange, ITerminalAddon, Terminal } from '@xterm/xterm';
 import type { IHTMLSerializeOptions, SerializeAddon as ISerializeApi, ISerializeOptions, ISerializeRange } from '@xterm/addon-serialize';
-import { IAttributeData, IColor } from 'common/Types';
+import { IColor } from 'common/Types';
+import { IAttributeData } from 'common/buffer/Types';
 import { DEFAULT_ANSI_COLORS } from 'browser/Types';
 import { UnderlineStyle } from 'common/buffer/Constants';
 
@@ -172,7 +173,7 @@ class StringSerializeHandler extends BaseSerializeHandler {
   private _thisRowLastSecondChar: IBufferCell = this._buffer.getNullCell();
   private _nextRowFirstChar: IBufferCell = this._buffer.getNullCell();
   protected _rowEnd(row: number, isLastRow: boolean): void {
-    // if there is colorful empty cell at line end, whe must pad it back, or the the color block
+    // if there is colorful empty cell at line end, we must pad it back, or the color block
     // will missing
     if (this._nullCellCount > 0 && !equalBg(this._cursorStyle, this._backgroundCell)) {
       // use clear right to set background.
@@ -220,7 +221,7 @@ class StringSerializeHandler extends BaseSerializeHandler {
             // you can't use control sequence to move cursor to (x === row)
             (thisRowLastChar.getChars() || thisRowLastChar.getWidth() === 0) &&
             // change background of the first wrapped cell also affects BCE
-            // so we mark it as invalid to simply the process to determine line separator
+            // so we mark it as invalid to simplify the process to determine line separator
             equalBg(thisRowLastChar, nextRowFirstChar)
           ) {
             isValid = true;
@@ -232,7 +233,7 @@ class StringSerializeHandler extends BaseSerializeHandler {
             isNextRowFirstCharDoubleWidth &&
             (thisRowLastSecondChar.getChars() || thisRowLastSecondChar.getWidth() === 0) &&
             // change background of the first wrapped cell also affects BCE
-            // so we mark it as invalid to simply the process to determine line separator
+            // so we mark it as invalid to simplify the process to determine line separator
             equalBg(thisRowLastChar, nextRowFirstChar) &&
             equalBg(thisRowLastSecondChar, nextRowFirstChar)
           ) {

addons/addon-serialize/test/SerializeAddon.test.ts

@@ -192,7 +192,7 @@ test.describe('SerializeAddon', () => {
     const cols = 10;
     const line = '+'.repeat(cols);
     const lines: string[] = [
-      sgr(FG_P16_GREEN) + line,  // Workaround: If we clear all flags a the end, serialize will use \x1b[0m to clear instead of the sepcific disable sequence
+      sgr(FG_P16_GREEN) + line,  // Workaround: If we clear all flags at the end, serialize will use \x1b[0m to clear instead of the specific disable sequence
       sgr(INVERSE) + line,
       sgr(BOLD) + line,
       sgr(UNDERLINED) + line,

addons/addon-unicode-graphemes/src/UnicodeGraphemesAddon.ts

@@ -2,7 +2,7 @@
  * Copyright (c) 2023 The xterm.js authors. All rights reserved.
  * @license MIT
  *
- * UnicodeVersionProvider for V15 with grapeme cluster handleing.
+ * UnicodeVersionProvider for V15 with grapheme cluster handling.
  */
 
 import type { Terminal, ITerminalAddon, IUnicodeHandling } from '@xterm/xterm';

addons/addon-web-links/src/WebLinkProvider.ts

@@ -57,7 +57,8 @@ function isUrl(urlString: string): boolean {
 
 export class LinkComputer {
   public static computeLink(y: number, regex: RegExp, terminal: Terminal, activate: (event: MouseEvent, uri: string) => void): ILink[] {
-    const rex = new RegExp(regex.source, (regex.flags || '') + 'g');
+    const flags = regex.flags.includes('g') ? regex.flags : `${regex.flags}g`;
+    const rex = new RegExp(regex.source, flags);
 
     const [lines, startLineIndex] = LinkComputer._getWindowedLineStrings(y - 1, terminal);
     const line = lines.join('');

addons/addon-web-links/src/WebLinksAddon.ts

@@ -7,13 +7,13 @@ import type { Terminal, ITerminalAddon, IDisposable } from '@xterm/xterm';
 import type { WebLinksAddon as IWebLinksApi } from '@xterm/addon-web-links';
 import { ILinkProviderOptions, WebLinkProvider } from './WebLinkProvider';
 
-// consider everthing starting with http:// or https://
+// consider everything starting with http:// or https://
 // up to first whitespace, `"` or `'` as url
 // NOTE: The repeated end clause is needed to not match a dangling `:`
 // resembling the old (...)*([^:"\'\\s]) final path clause
 // additionally exclude early + final:
 // - unsafe from rfc3986: !*'()
-// - unsafe chars from rfc1738: {}|\^~[]` (minus [] as we need them for ipv6 adresses, also allow ~)
+// - unsafe chars from rfc1738: {}|\^~[]` (minus [] for ipv6 addresses, also allow ~)
 // also exclude as finals:
 // - final interpunction like ,.!?
 // - any sort of brackets <>()[]{} (not spec conform, but often used to enclose urls)

addons/addon-webgl/README.md

@@ -23,7 +23,7 @@ See the full [API](https://github.com/xtermjs/xterm.js/blob/master/addons/addon-
 
 ### Handling Context Loss
 
-The browser may drop WebGL contexts for various reasons like OOM or after the system has been suspended. There is an API exposed that fires the `webglcontextlost` event fired on the canvas so embedders can handle it however they wish. An easy, but suboptimal way, to handle this is by disposing of WebglAddon when the event fires:
+The browser may drop WebGL contexts for various reasons like OOM or after the system has been suspended. There is an API exposed that fires the `webglcontextlost` event on the canvas so embedders can handle it however they wish. An easy, but suboptimal way, to handle this is by disposing of WebglAddon when the event fires:
 
 ```ts
 const terminal = new Terminal();

addons/addon-webgl/src/CellColorResolver.ts

@@ -3,7 +3,7 @@ import { ICoreBrowserService, IThemeService } from 'browser/services/Services';
 import { ReadonlyColorSet } from 'browser/Types';
 import { Attributes, BgFlags, ExtFlags, FgFlags, NULL_CELL_CODE, UnderlineStyle } from 'common/buffer/Constants';
 import { IDecorationService, IOptionsService } from 'common/services/Services';
-import { ICellData } from 'common/Types';
+import { ICellData } from 'common/buffer/Types';
 import { Terminal } from '@xterm/xterm';
 import { rgba } from 'common/Color';
 import { treatGlyphAsBackgroundColor } from 'browser/renderer/shared/RendererUtils';

addons/addon-webgl/src/GlyphRenderer.ts

@@ -220,7 +220,7 @@ export class GlyphRenderer extends Disposable {
   public updateCell(x: number, y: number, code: number, bg: number, fg: number, ext: number, chars: string, width: number, lastBg: number): void {
     // Since this function is called for every cell (`rows*cols`), it must be very optimized. It
     // should not instantiate any variables unless a new glyph is drawn to the cache where the
-    // slight slowdown is acceptable for the developer ergonomics provided as it's a once of for
+    // slight slowdown is acceptable for the developer ergonomics provided as it's a one-off for
     // each glyph.
     this._updateCell(this._vertices.attributes, x, y, code, bg, fg, ext, chars, width, lastBg);
   }

addons/addon-webgl/src/TextureAtlas.ts

@@ -69,7 +69,7 @@ export class TextureAtlas implements ITextureAtlas {
   private _overflowSizePage: AtlasPage | undefined;
 
   private _tmpCanvas: HTMLCanvasElement;
-  // A temporary context that glyphs are drawn to before being transfered to the atlas.
+  // A temporary context that glyphs are drawn to before being transferred to the atlas.
   private _tmpCtx: CanvasRenderingContext2D;
 
   private _workBoundingBox: IBoundingBox = { top: 0, left: 0, bottom: 0, right: 0 };
@@ -152,7 +152,7 @@ export class TextureAtlas implements ITextureAtlas {
   }
 
   private _createNewPage(): AtlasPage {
-    // Try merge the set of the 4 most used pages of the largest size. This is is deferred to a
+    // Try merge the set of the 4 most used pages of the largest size. This is deferred to a
     // microtask to ensure it does not interrupt textures that will be rendered in the current
     // animation frame which would result in blank rendered areas. This is actually not that
     // expensive relative to drawing the glyphs, so there is no need to wait for an idle callback.
@@ -191,7 +191,7 @@ export class TextureAtlas implements ITextureAtlas {
         return newPage;
       }
 
-      const sortedMergingPagesIndexes = mergingPages.map(e => e.glyphs[0].texturePage).sort((a, b) => a > b ? 1 : -1);
+      const sortedMergingPagesIndexes = mergingPages.map(e => e.glyphs[0].texturePage).sort((a, b) => a - b);
       const mergedPageIndex = this.pages.length - mergingPages.length;
 
       // Merge into the new page
@@ -1125,7 +1125,7 @@ function clearColor(imageData: ImageData, bg: IColor, fg: IColor, enableThreshol
   // were covered (fg=#8ae234, bg=#c4a000).
   const threshold = Math.floor((Math.abs(r - fgR) + Math.abs(g - fgG) + Math.abs(b - fgB)) / 12);
 
-  // Set alpha channel of relevent pixels to 0
+  // Set alpha channel of relevant pixels to 0
   let isEmpty = true;
   for (let offset = 0; offset < imageData.data.length; offset += 4) {
     // Check exact match

addons/addon-webgl/src/WebglAddon.ts

@@ -40,7 +40,7 @@ export class WebglAddon extends Disposable implements ITerminalAddon, IWebglApi
       };
       const gl = document.createElement('canvas').getContext('webgl2', contextAttributes) as IWebGL2RenderingContext;
       if (!gl) {
-        throw new Error('Webgl2 is only supported on Safari 16 and above');
+        throw new Error('WebGL2 is only supported on Safari 16 and above');
       }
     }
     super();

addons/addon-webgl/src/WebglRenderer.ts

@@ -10,7 +10,7 @@ import { CursorBlinkStateManager } from './CursorBlinkStateManager';
 import { observeDevicePixelDimensions } from './DevicePixelObserver';
 import { IRenderDimensions, IRenderer, IRequestRedrawEvent } from 'browser/renderer/shared/Types';
 import { ICharSizeService, ICharacterJoinerService, ICoreBrowserService, IThemeService } from 'browser/services/Services';
-import { CharData, IBufferLine, ICellData } from 'common/Types';
+import { CharData, IBufferLine, ICellData } from 'common/buffer/Types';
 import { AttributeData } from 'common/buffer/AttributeData';
 import { CellData } from 'common/buffer/CellData';
 import { Attributes, Content, FgFlags, NULL_CELL_CHAR, NULL_CELL_CODE } from 'common/buffer/Constants';
@@ -664,10 +664,10 @@ export class WebglRenderer extends Disposable implements IRenderer {
     this.dimensions.device.canvas.height = this._terminal.rows * this.dimensions.device.cell.height;
     this.dimensions.device.canvas.width = this._terminal.cols * this.dimensions.device.cell.width;
 
-    // The the size of the canvas on the page. It's important that this rounds to nearest integer
+    // The size of the canvas on the page. It's important that this rounds to nearest integer
     // and not ceils as browsers often have floating point precision issues where
     // `window.devicePixelRatio` ends up being something like `1.100000023841858` for example, when
-    // it's actually 1.1. Ceiling may causes blurriness as the backing canvas image is 1 pixel too
+    // it's actually 1.1. Ceiling may cause blurriness as the backing canvas image is 1 pixel too
     // large for the canvas element size.
     this.dimensions.css.canvas.height = Math.round(this.dimensions.device.canvas.height / this._devicePixelRatio);
     this.dimensions.css.canvas.width = Math.round(this.dimensions.device.canvas.width / this._devicePixelRatio);

addons/addon-webgl/src/customGlyphs/CustomGlyphRasterizer.ts

@@ -221,8 +221,8 @@ function drawPathDefinitionCharacter(
       const rx = parseFloat(args[0]) * deviceCellWidth;
       const ry = parseFloat(args[1]) * deviceCellHeight;
       const xAxisRotation = parseFloat(args[2]) * Math.PI / 180;
-      const largeArcFlag = parseInt(args[3]);
-      const sweepFlag = parseInt(args[4]);
+      const largeArcFlag = parseInt(args[3], 10);
+      const sweepFlag = parseInt(args[4], 10);
       const x = xOffset + parseFloat(args[5]) * deviceCellWidth;
       const y = yOffset + parseFloat(args[6]) * deviceCellHeight;
       drawSvgArc(ctx, currentX, currentY, rx, ry, xAxisRotation, largeArcFlag, sweepFlag, x, y);

addons/addon-webgl/typings/addon-webgl.d.ts

@@ -23,12 +23,12 @@ declare module '@xterm/addon-webgl' {
     public readonly onChangeTextureAtlas: IEvent<HTMLCanvasElement>;
 
     /**
-     * An event that is fired when the a new page is added to the texture atlas.
+     * An event that is fired when a new page is added to the texture atlas.
      */
     public readonly onAddTextureAtlasCanvas: IEvent<HTMLCanvasElement>;
 
     /**
-     * An event that is fired when the a page is removed from the texture atlas.
+     * An event that is fired when a page is removed from the texture atlas.
      */
     public readonly onRemoveTextureAtlasCanvas: IEvent<HTMLCanvasElement>;
 

bin/esbuild_all.mjs

@@ -19,14 +19,17 @@ for (const addon of addons) {
 // Demo job - This requires the others to be built so it's not included when building all
 // jobs.push(createJob('demo-client', [`--demo-client`]));
 
-await Promise.all(jobs.map((job, i) => {
+const codes = await Promise.all(jobs.map(job => {
   return new Promise(r => {
     job.cp.on('exit', code => {
       log(`Finished \x1b[32m${job.name}\x1b[0m${code ? ' \x1b[31mwith errors\x1b[0m' : ''}`);
-      r(code);
+      r(code ?? 1);
     });
   });
 }));
+if (codes.some(code => code !== 0)) {
+  process.exit(1);
+}
 
 /**
  * @param {string} message

bin/setup-full.mjs

@@ -5,7 +5,7 @@ import { spawnSync } from 'node:child_process';
 import { basename, dirname, resolve, sep } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
-const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), '../..');
+const repoRoot = resolve(dirname(fileURLToPath(import.meta.url)), '..');
 const nodeModulesPath = resolve(repoRoot, 'node_modules');
 const npmExecutable = process.platform === 'win32' ? 'npm.cmd' : 'npm';
 
@@ -13,7 +13,7 @@ const npmExecutable = process.platform === 'win32' ? 'npm.cmd' : 'npm';
 
 /** @param {string} message */
 function log(message) {
-  console.info(`[setup-fast] ${message}`);
+  console.info(`[setup-full] ${message}`);
 }
 
 /** @param {string[]} args */

bin/test_integration.js

@@ -12,7 +12,7 @@ let argv = process.argv.slice(2);
 let suiteFilter = undefined;
 while (argv.some(e => e.startsWith('--suite='))) {
   const i = argv.findIndex(e => e.startsWith('--suite='));
-  const match = argv[i].match(/--suite=(?<suitename>.+)/)
+  const match = argv[i].match(/--suite=(?<suitename>.+)/);
   suiteFilter = match?.groups?.suitename ?? undefined;
   argv.splice(i, 1);
 }
@@ -42,12 +42,18 @@ if (suiteFilter) {
   configs = configs.filter(e => e.name === suiteFilter);
 }
 
+if (suiteFilter && configs.length === 0) {
+  console.error(`Unknown suite: ${suiteFilter}`);
+  process.exit(1);
+}
+
 function npmBinScript(script) {
   return path.resolve(__dirname, `../node_modules/.bin/` + (process.platform === 'win32' ?
     `${script}.cmd` : script));
 }
 
 async function run() {
+  let exitCode = 0;
   for (const config of configs) {
     const command = npmBinScript('playwright');
     const args = ['test', '-c', config.path, ...argv];
@@ -62,10 +68,13 @@ async function run() {
 
     if (run.error) {
       console.error(run.error);
-      process.exit(run.status ?? -1);
+      process.exit(run.status ?? 1);
     }
 
-    process.exit(run.status);
+    if (run.status) {
+      exitCode = run.status;
+    }
   }
+  process.exit(exitCode);
 }
 run();

bin/test_mousemodes.js

@@ -177,7 +177,7 @@ const ENC = {
 }
 
 function printMenu() {
-  console.log('\x1b[2J\x1b\[HTest mouse reports [Ctrl-C to exit]');
+  console.log('\x1b[2J\x1b[HTest mouse reports [Ctrl-C to exit]');
   console.log();
   console.log('  Selected protocol [Ctrl-A to switch]');
   const protocols = Object.keys(PROTOCOLS);

bin/test_unit.js

@@ -21,7 +21,7 @@ if (process.argv.length > 2) {
   flagArgs = args.filter(e => e.startsWith('--'));
   // ability to inject particular test files via
   // npm run test [testFileA testFileB ...]
-  files = args.filter(e => !e.startsWith('--'));
+  const files = args.filter(e => !e.startsWith('--'));
   if (files.length) {
     testFiles = files;
   }
@@ -39,8 +39,6 @@ if (checkCoverage) {
     ...testFiles,
     ...flagArgs
   ];
-  console.info('executable', executable);
-  console.info('args', args);
   const run = cp.spawnSync(
     executable,
     args,
@@ -51,7 +49,7 @@ if (checkCoverage) {
       stdio: 'inherit'
     }
   );
-  process.exit(run.status);
+  process.exit(run.status ?? -1);
 }
 
 const run = cp.spawnSync(

package-lock.json

@@ -6689,16 +6689,6 @@
         "url": "https://github.com/sponsors/ljharb"
       }
     },
-    "node_modules/randombytes": {
-      "version": "2.1.0",
-      "resolved": "https://registry.npmjs.org/randombytes/-/randombytes-2.1.0.tgz",
-      "integrity": "sha512-vYl3iOX+4CKUWuxGi9Ukhie6fsqXqS9FE2Zaic4tNFD2N2QQaXOMFbuKK4QmDHC0JO6B1Zp41J0LpT0oR68amQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "safe-buffer": "^5.1.0"
-      }
-    },
     "node_modules/range-parser": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/range-parser/-/range-parser-1.2.1.tgz",
@@ -6932,27 +6922,6 @@
         "tslib": "^2.1.0"
       }
     },
-    "node_modules/safe-buffer": {
-      "version": "5.2.1",
-      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.2.1.tgz",
-      "integrity": "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==",
-      "dev": true,
-      "funding": [
-        {
-          "type": "github",
-          "url": "https://github.com/sponsors/feross"
-        },
-        {
-          "type": "patreon",
-          "url": "https://www.patreon.com/feross"
-        },
-        {
-          "type": "consulting",
-          "url": "https://feross.org/support"
-        }
-      ],
-      "license": "MIT"
-    },
     "node_modules/safer-buffer": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
@@ -7078,13 +7047,13 @@
       }
     },
     "node_modules/serialize-javascript": {
-      "version": "6.0.2",
-      "resolved": "https://registry.npmjs.org/serialize-javascript/-/serialize-javascript-6.0.2.tgz",
-      "integrity": "sha512-Saa1xPByTTq2gdeFZYLLo+RFE35NHZkAbqZeWNd3BpzppeVisAqpDjcp8dyf6uIvEqJRd46jemmyA4iFIeVk8g==",
+      "version": "7.0.5",
+      "resolved": "https://registry.npmjs.org/serialize-javascript/-/serialize-javascript-7.0.5.tgz",
+      "integrity": "sha512-F4LcB0UqUl1zErq+1nYEEzSHJnIwb3AF2XWB94b+afhrekOUijwooAYqFyRbjYkm2PAKBabx6oYv/xDxNi8IBw==",
       "dev": true,
       "license": "BSD-3-Clause",
-      "dependencies": {
-        "randombytes": "^2.1.0"
+      "engines": {
+        "node": ">=20.0.0"
       }
     },
     "node_modules/serve-static": {

package.json

@@ -11,6 +11,9 @@
   "workspaces": [
     "addons/*"
   ],
+  "overrides": {
+    "serialize-javascript": "^7.0.3"
+  },
   "keywords": [
     "cli",
     "command-line",
@@ -61,9 +64,9 @@
     "test-integration-firefox": "node ./bin/test_integration.js --workers=75% \"--project=FirefoxStable\"",
     "test-integration-webkit": "node ./bin/test_integration.js --workers=75% \"--project=WebKit\"",
     "test-integration-debug": "node ./bin/test_integration.js  --workers=1 --headed --timeout=30000",
-    "benchmark": "xterm-benchmark -r 5 -c test/benchmark/benchmark.json",
-    "benchmark-baseline": "xterm-benchmark -r 5 -c test/benchmark/benchmark.json --baseline out-test/benchmark/*benchmark.js",
-    "benchmark-eval": "xterm-benchmark -r 5 -c test/benchmark/benchmark.json --eval out-test/benchmark/*benchmark.js",
+    "benchmark": "NODE_PATH=./out xterm-benchmark -r 5 -c test/benchmark/benchmark.json",
+    "benchmark-baseline": "NODE_PATH=./out xterm-benchmark -r 5 -c test/benchmark/benchmark.json --baseline out-test/benchmark/*benchmark.js",
+    "benchmark-eval": "NODE_PATH=./out xterm-benchmark -r 5 -c test/benchmark/benchmark.json --eval out-test/benchmark/*benchmark.js",
     "clean": "rm -rf lib out addons/*/lib addons/*/out",
     "vtfeatures": "node bin/extract_vtfeatures.js src/*/*.ts src/*/*/*.ts src/*.ts addons/**/src/*.ts",
     "prepackage": "npm run build",

src/browser/CoreBrowserTerminal.ts

@@ -102,7 +102,7 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
   private _keyDownHandled: boolean = false;
 
   /**
-   * Records whether a keydown event has occured since the last keyup event, i.e. whether a key
+   * Records whether a keydown event has occurred since the last keyup event, i.e. whether a key
    * is currently "pressed".
    */
   private _keyDownSeen: boolean = false;
@@ -505,7 +505,7 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
       this.textarea,
       parent.ownerDocument.defaultView ?? window,
       // Force unsafe null in node.js environment for tests
-      this._document ?? (typeof window !== 'undefined') ? window.document : null as any
+      this._document ?? ((typeof window !== 'undefined') ? window.document : null as any)
     ));
     this._instantiationService.setService(ICoreBrowserService, this._coreBrowserService);
 

src/browser/OscLinkProvider.test.ts

@@ -8,7 +8,8 @@ import { OscLinkProvider } from './OscLinkProvider';
 import { ILink } from './Types';
 import { createCellData, MockBufferService, MockOptionsService } from '../common/TestUtils.test';
 import { IBufferService, IOscLinkService } from '../common/services/Services';
-import { IBufferLine, IOscLinkData } from '../common/Types';
+import { IOscLinkData } from '../common/Types';
+import { IBufferLine } from '../common/buffer/Types';
 
 class TestOscLinkService implements IOscLinkService {
   public serviceBrand: any;

src/browser/OscLinkProvider.ts

@@ -6,7 +6,7 @@
 import { IBufferRange, ILink } from './Types';
 import { ILinkProvider } from './services/Services';
 import { CellData } from '../common/buffer/CellData';
-import { IBufferLine } from '../common/Types';
+import { IBufferLine } from '../common/buffer/Types';
 import { IBufferService, IOptionsService, IOscLinkService } from '../common/services/Services';
 
 export class OscLinkProvider implements ILinkProvider {

src/browser/RenderDebouncer.ts

@@ -23,7 +23,7 @@ export class RenderDebouncer implements IRenderDebouncerWithCallback {
   }
 
   public dispose(): void {
-    if (this._animationFrame) {
+    if (this._animationFrame !== undefined) {
       this._coreBrowserService.window.cancelAnimationFrame(this._animationFrame);
       this._animationFrame = undefined;
     }
@@ -31,9 +31,7 @@ export class RenderDebouncer implements IRenderDebouncerWithCallback {
 
   public addRefreshCallback(callback: FrameRequestCallback): number {
     this._refreshCallbacks.push(callback);
-    if (!this._animationFrame) {
-      this._animationFrame = this._coreBrowserService.window.requestAnimationFrame(() => this._innerRefresh());
-    }
+    this._animationFrame ??= this._coreBrowserService.window.requestAnimationFrame(() => this._innerRefresh());
     return this._animationFrame;
   }
 
@@ -46,7 +44,7 @@ export class RenderDebouncer implements IRenderDebouncerWithCallback {
     this._rowStart = this._rowStart !== undefined ? Math.min(this._rowStart, rowStart) : rowStart;
     this._rowEnd = this._rowEnd !== undefined ? Math.max(this._rowEnd, rowEnd) : rowEnd;
 
-    if (this._animationFrame) {
+    if (this._animationFrame !== undefined) {
       return;
     }
 

src/browser/Terminal.test.ts

@@ -9,7 +9,7 @@ import { assert } from 'chai';
 import { DEFAULT_ATTR_DATA } from '../common/buffer/BufferLine';
 import { CellData } from '../common/buffer/CellData';
 import { MockUnicodeService, createCellData } from '../common/TestUtils.test';
-import { IMarker } from '../common/Types';
+import { IMarker } from '../common/buffer/Types';
 
 const INIT_COLS = 80;
 const INIT_ROWS = 24;

src/browser/TestUtils.test.ts

@@ -7,8 +7,9 @@ import { IDisposable, IMarker, ILinkProvider, IDecorationOptions, IDecoration, I
 import { ICharacterJoinerService, ICharSizeService, ICoreBrowserService, IMouseService, IRenderService, ISelectionService, IThemeService } from './services/Services';
 import { IRenderDimensions, IRenderer, IRequestRedrawEvent } from './renderer/shared/Types';
 import { IColorSet, ITerminal, ILinkifier2, IBrowser, IViewport, ICompositionHelper, CharacterJoinerHandler, IBufferRange, ReadonlyColorSet, IBufferElementProvider } from './Types';
-import { IBuffer, IBufferSet } from '../common/buffer/Types';
-import { IBufferLine, ICellData, IAttributeData, ICircularList, XtermListener, ICharset, ITerminalOptions, ColorIndex } from '../common/Types';
+import { IAttributeData, IBuffer, IBufferLine, IBufferSet, ICellData } from '../common/buffer/Types';
+import { ICircularList } from '../common/CircularList';
+import { XtermListener, ICharset, ITerminalOptions, ColorIndex } from '../common/Types';
 import { Buffer } from '../common/buffer/Buffer';
 import * as Browser from '../common/Platform';
 import { CoreBrowserTerminal } from './CoreBrowserTerminal';

src/browser/TimeBasedDebouncer.ts

@@ -3,10 +3,10 @@
  * @license MIT
  */
 
-const RENDER_DEBOUNCE_THRESHOLD_MS = 1000; // 1 Second
-
 import { IRenderDebouncer } from './Types';
 
+const RENDER_DEBOUNCE_THRESHOLD_MS = 1000; // 1 Second
+
 /**
  * Debounces calls to update screen readers to update at most once configurable interval of time.
  */
@@ -31,7 +31,9 @@ export class TimeBasedDebouncer implements IRenderDebouncer {
   public dispose(): void {
     if (this._refreshTimeoutID) {
       clearTimeout(this._refreshTimeoutID);
+      this._refreshTimeoutID = undefined;
     }
+    this._additionalRefreshRequested = false;
   }
 
   public refresh(rowStart: number | undefined, rowEnd: number | undefined, rowCount: number): void {
@@ -47,7 +49,12 @@ export class TimeBasedDebouncer implements IRenderDebouncer {
     // enough time to pass before refreshing again.
     const refreshRequestTime: number = performance.now();
     if (refreshRequestTime - this._lastRefreshMs >= this._debounceThresholdMS) {
-      // Enough time has lapsed since the last refresh; refresh immediately
+      // Enough time has elapsed since the last refresh; refresh immediately
+      if (this._refreshTimeoutID !== undefined) {
+        clearTimeout(this._refreshTimeoutID);
+        this._refreshTimeoutID = undefined;
+        this._additionalRefreshRequested = false;
+      }
       this._lastRefreshMs = refreshRequestTime;
       this._innerRefresh();
     } else if (!this._additionalRefreshRequested) {

src/browser/Types.ts

@@ -3,8 +3,9 @@
  * @license MIT
  */
 
-import { CharData, IColor, ICoreTerminal, ITerminalOptions } from '../common/Types';
-import { IBuffer } from '../common/buffer/Types';
+import { IColor, ITerminalOptions } from '../common/Types';
+import { CharData, IBuffer } from '../common/buffer/Types';
+import { ICoreTerminal } from '../common/CoreTerminal';
 import { IDisposable, IRenderDimensions as IRenderDimensionsApi, Terminal as ITerminalApi } from '@xterm/xterm';
 import { channels, css } from '../common/Color';
 import type { IEvent } from '../common/Event';

src/browser/input/Mouse.ts

@@ -6,8 +6,8 @@
 export function getCoordsRelativeToElement(window: Pick<Window, 'getComputedStyle'>, event: {clientX: number, clientY: number}, element: HTMLElement): [number, number] {
   const rect = element.getBoundingClientRect();
   const elementStyle = window.getComputedStyle(element);
-  const leftPadding = parseInt(elementStyle.getPropertyValue('padding-left'));
-  const topPadding = parseInt(elementStyle.getPropertyValue('padding-top'));
+  const leftPadding = parseInt(elementStyle.getPropertyValue('padding-left'), 10);
+  const topPadding = parseInt(elementStyle.getPropertyValue('padding-top'), 10);
   return [
     event.clientX - rect.left - leftPadding,
     event.clientY - rect.top - topPadding
@@ -22,7 +22,7 @@ export function getCoordsRelativeToElement(window: Pick<Window, 'getComputedStyl
  * @param event The mouse event.
  * @param element The terminal's container element.
  * @param colCount The number of columns in the terminal.
- * @param rowCount The number of rows n the terminal.
+ * @param rowCount The number of rows in the terminal.
  * @param hasValidCharSize Whether there is a valid character size available.
  * @param cssCellWidth The cell width device pixel render dimensions.
  * @param cssCellHeight The cell height device pixel render dimensions.
@@ -31,21 +31,17 @@ export function getCoordsRelativeToElement(window: Pick<Window, 'getComputedStyl
  * select that cell and the right half will select the next cell.
  */
 export function getCoords(window: Pick<Window, 'getComputedStyle'>, event: Pick<MouseEvent, 'clientX' | 'clientY'>, element: HTMLElement, colCount: number, rowCount: number, hasValidCharSize: boolean, cssCellWidth: number, cssCellHeight: number, isSelection?: boolean): [number, number] | undefined {
-  // Coordinates cannot be measured if there are no valid
+  // Coordinates cannot be measured if there is no valid character size.
   if (!hasValidCharSize) {
     return undefined;
   }
 
   const coords = getCoordsRelativeToElement(window, event, element);
-  if (!coords) {
-    return undefined;
-  }
-
   coords[0] = Math.ceil((coords[0] + (isSelection ? cssCellWidth / 2 : 0)) / cssCellWidth);
   coords[1] = Math.ceil(coords[1] / cssCellHeight);
 
   // Ensure coordinates are within the terminal viewport. Note that selections
-  // need an addition point of precision to cover the end point (as characters
+  // need an additional point of precision to cover the end point (as characters
   // cover half of one char and half of the next).
   coords[0] = Math.min(Math.max(coords[0], 1), colCount + (isSelection ? 1 : 0));
   coords[1] = Math.min(Math.max(coords[1], 1), rowCount);

src/browser/input/MoveToCell.ts

@@ -156,7 +156,7 @@ function wrappedRowsForRow(currentRow: number, bufferService: IBufferService): n
  */
 function horizontalDirection(startX: number, startY: number, targetX: number, targetY: number, bufferService: IBufferService, applicationCursor: boolean): Direction {
   let startRow;
-  if (moveToRequestedRow(targetX, targetY, bufferService, applicationCursor).length > 0) {
+  if (moveToRequestedRow(startY, targetY, bufferService, applicationCursor).length > 0) {
     startRow = targetY - wrappedRowsForRow(targetY, bufferService);
   } else {
     startRow = startY;

src/browser/renderer/dom/DomRenderer.ts

@@ -694,7 +694,7 @@ class CursorBlinkStateManager {
   }
 
   private _clearIdleTimer(): void {
-    if (this._idleTimeout) {
+    if (this._idleTimeout !== undefined) {
       this._coreBrowserService.window.clearTimeout(this._idleTimeout);
       this._idleTimeout = undefined;
     }

src/browser/renderer/dom/DomRendererRowFactory.test.ts

@@ -9,7 +9,7 @@ import { DomRendererRowFactory } from './DomRendererRowFactory';
 import { NULL_CELL_CODE, NULL_CELL_WIDTH, NULL_CELL_CHAR, DEFAULT_ATTR, FgFlags, BgFlags, Attributes, UnderlineStyle } from '../../../common/buffer/Constants';
 import { BufferLine, DEFAULT_ATTR_DATA } from '../../../common/buffer/BufferLine';
 import { BufferLineStringCache } from '../../../common/buffer/BufferLineStringCache';
-import { IBufferLine } from '../../../common/Types';
+import { IBufferLine } from '../../../common/buffer/Types';
 import { CellData } from '../../../common/buffer/CellData';
 import { MockCoreService, MockDecorationService, MockOptionsService, createCellData, NULL_CELL_DATA } from '../../../common/TestUtils.test';
 import { MockCharacterJoinerService, MockCoreBrowserService, MockThemeService } from '../../TestUtils.test';

src/browser/renderer/dom/DomRendererRowFactory.ts

@@ -3,7 +3,8 @@
  * @license MIT
  */
 
-import { IBufferLine, ICellData, IColor } from '../../../common/Types';
+import { IColor } from '../../../common/Types';
+import { IBufferLine, ICellData } from '../../../common/buffer/Types';
 import { INVERTED_DEFAULT_COLOR } from '../shared/Constants';
 import { WHITESPACE_CELL_CHAR, Attributes } from '../../../common/buffer/Constants';
 import { CellData } from '../../../common/buffer/CellData';

src/browser/scrollable/mouseEvent.ts

@@ -217,7 +217,7 @@ export class StandardWheelEvent {
     let shouldFactorDPR: boolean = false;
     if (platform.isChrome) {
       const chromeVersionMatch = navigator.userAgent.match(/Chrome\/(\d+)/);
-      const chromeMajorVersion = chromeVersionMatch ? parseInt(chromeVersionMatch[1]) : 123;
+      const chromeMajorVersion = chromeVersionMatch ? parseInt(chromeVersionMatch[1], 10) : 123;
       shouldFactorDPR = chromeMajorVersion <= 122;
     }
 

src/browser/services/CharacterJoinerService.test.ts

@@ -8,7 +8,7 @@ import { ICharacterJoinerService } from './Services';
 import { CharacterJoinerService } from './CharacterJoinerService';
 import { BufferLine } from '../../common/buffer/BufferLine';
 import { BufferLineStringCache } from '../../common/buffer/BufferLineStringCache';
-import { IBufferLine } from '../../common/Types';
+import { IBufferLine } from '../../common/buffer/Types';
 import { CellData } from '../../common/buffer/CellData';
 import { MockBufferService, createCellData } from '../../common/TestUtils.test';
 

src/browser/services/CharacterJoinerService.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { IBufferLine, ICellData, CharData } from '../../common/Types';
+import { CharData, IBufferLine, ICellData } from '../../common/buffer/Types';
 import { ICharacterJoiner } from '../Types';
 import { AttributeData } from '../../common/buffer/AttributeData';
 import { WHITESPACE_CELL_CHAR, Content } from '../../common/buffer/Constants';

src/browser/services/MouseService.test.ts

@@ -176,7 +176,7 @@ describe('MouseService _triggerMouseEvent', () => {
       for (let i = 0; i < bufferService.cols; ++i) {
         assert.equal(trigger({ col: i, row: 0, x: 0, y: 0, button: CoreMouseButton.LEFT, action: CoreMouseAction.DOWN }), true);
         if (i > 222) {
-          // supress mouse reports if we are out of addressible range (max. 222)
+          // suppress mouse reports if we are out of addressable range (max. 222)
           assert.deepEqual(toBytes(reports.pop()), []);
         } else {
           assert.deepEqual(toBytes(reports.pop()), [0x1b, 0x5b, 0x4d, 0x20, i + 33, 0x21]);

src/browser/services/SelectionService.test.ts

@@ -6,14 +6,13 @@
 import { assert } from 'chai';
 import { SelectionService, SelectionMode } from './SelectionService';
 import { SelectionModel } from '../selection/SelectionModel';
-import { IBufferLine } from '../../common/Types';
+import { IBuffer, IBufferLine } from '../../common/buffer/Types';
 import { MockBufferService, MockOptionsService, MockCoreService, MockMouseStateService, createCellData } from '../../common/TestUtils.test';
 import { BufferLine } from '../../common/buffer/BufferLine';
 import { BufferLineStringCache } from '../../common/buffer/BufferLineStringCache';
 import { IBufferService, IOptionsService } from '../../common/services/Services';
 import { MockCoreBrowserService, MockMouseService, MockRenderService } from '../TestUtils.test';
 import { CellData } from '../../common/buffer/CellData';
-import { IBuffer } from '../../common/buffer/Types';
 import { IRenderService } from './Services';
 
 const TEST_STRING_CACHE = new BufferLineStringCache();

src/browser/services/SelectionService.ts

@@ -11,10 +11,10 @@ import { ISelectionRedrawRequestEvent, ISelectionRequestScrollLinesEvent } from
 import { ICoreBrowserService, IMouseCoordsService, IRenderService, ISelectionService } from './Services';
 import { Disposable, MutableDisposable, toDisposable } from '../../common/Lifecycle';
 import * as Browser from '../../common/Platform';
-import { IBufferLine, ICellData, IDisposable } from '../../common/Types';
+import { IDisposable } from '../../common/Types';
+import { IBuffer, IBufferLine, ICellData } from '../../common/buffer/Types';
 import { getRangeLength } from '../../common/buffer/BufferRange';
 import { CellData } from '../../common/buffer/CellData';
-import { IBuffer } from '../../common/buffer/Types';
 import { IBufferService, ICoreService, IMouseStateService, IOptionsService } from '../../common/services/Services';
 import { Emitter } from '../../common/Event';
 

src/browser/services/ThemeService.ts

@@ -132,7 +132,7 @@ export class ThemeService extends Disposable implements IThemeService {
         colors.ansi[i + 16] = parseColor(theme.extendedAnsi[i], DEFAULT_ANSI_COLORS[i + 16]);
       }
     }
-    // Clear our the cache
+    // Clear the cache
     this._contrastCache.clear();
     this._halfContrastCache.clear();
     this._updateRestoreColors();

src/common/CircularList.ts

@@ -3,9 +3,8 @@
  * @license MIT
  */
 
-import { ICircularList } from './Types';
 import { Disposable } from './Lifecycle';
-import { Emitter } from './Event';
+import { Emitter, type IEvent } from './Event';
 
 export interface IInsertEvent {
   index: number;
@@ -17,6 +16,28 @@ export interface IDeleteEvent {
   amount: number;
 }
 
+export interface ICircularList<T> {
+  length: number;
+  maxLength: number;
+  isFull: boolean;
+
+  onDeleteEmitter: Emitter<IDeleteEvent>;
+  onDelete: IEvent<IDeleteEvent>;
+  onInsertEmitter: Emitter<IInsertEvent>;
+  onInsert: IEvent<IInsertEvent>;
+  onTrimEmitter: Emitter<number>;
+  onTrim: IEvent<number>;
+
+  get(index: number): T | undefined;
+  set(index: number, value: T): void;
+  push(value: T): void;
+  recycle(): T;
+  pop(): T | undefined;
+  splice(start: number, deleteCount: number, ...items: T[]): void;
+  trimStart(count: number): void;
+  shiftElements(start: number, count: number, offset: number): void;
+}
+
 /**
  * Represents a circular list; a list with a maximum size that wraps around when push is called,
  * overriding values at the start of the list.

src/common/Color.ts

@@ -177,9 +177,9 @@ export namespace css {
     // Formats: rgb() or rgba()
     const rgbaMatch = css.match(/rgba?\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*(,\s*(0|1|\d?\.(\d+))\s*)?\)/);
     if (rgbaMatch) {
-      $r = parseInt(rgbaMatch[1]);
-      $g = parseInt(rgbaMatch[2]);
-      $b = parseInt(rgbaMatch[3]);
+      $r = parseInt(rgbaMatch[1], 10);
+      $g = parseInt(rgbaMatch[2], 10);
+      $b = parseInt(rgbaMatch[3], 10);
       $a = Math.round((rgbaMatch[5] === undefined ? 1 : parseFloat(rgbaMatch[5])) * 0xFF);
       return channels.toColor($r, $g, $b, $a);
     }
@@ -373,7 +373,7 @@ export function toPaddedHex(c: number): string {
 /**
  * Gets the contrast ratio between two relative luminance values.
  * @param l1 The first relative luminance.
- * @param l2 The first relative luminance.
+ * @param l2 The second relative luminance.
  * @see https://www.w3.org/TR/WCAG20/#contrast-ratiodef
  */
 export function contrastRatio(l1: number, l2: number): number {

src/common/CoreTerminal.ts

@@ -21,19 +21,20 @@
  *   http://linux.die.net/man/7/urxvt
  */
 
-import { IInstantiationService, IOptionsService, IBufferService, ILogService, ICharsetService, ICoreService, IMouseStateService, IUnicodeService, LogLevelEnum, ITerminalOptions, IOscLinkService } from './services/Services';
+import { IInstantiationService, IOptionsService, IBufferService, ILogService, ICharsetService, ICoreService, IMouseStateService, IUnicodeService, LogLevelEnum, IOscLinkService } from './services/Services';
 import { InstantiationService } from './services/InstantiationService';
 import { LogService } from './services/LogService';
 import { BufferService, BufferServiceConstants } from './services/BufferService';
 import { OptionsService } from './services/OptionsService';
-import { IDisposable, IAttributeData, ICoreTerminal, IScrollEvent } from './Types';
+import { IDisposable, IScrollEvent, ITerminalOptions, IParams } from './Types';
+import { IAttributeData, IBufferSet } from './buffer/Types';
 import { CoreService } from './services/CoreService';
 import { MouseStateService } from './services/MouseStateService';
+import { UnicodeV6 } from './input/UnicodeV6';
 import { UnicodeService } from './services/UnicodeService';
 import { CharsetService } from './services/CharsetService';
 import { updateWindowsModeWrappedState } from './WindowsMode';
-import { IFunctionIdentifier, IParams } from './parser/Types';
-import { IBufferSet } from './buffer/Types';
+import { IFunctionIdentifier } from './parser/Types';
 import { InputHandler } from './InputHandler';
 import { WriteBuffer } from './input/WriteBuffer';
 import { OscLinkService } from './services/OscLinkService';
@@ -43,6 +44,20 @@ import { Disposable, MutableDisposable, toDisposable } from './Lifecycle';
 // Only trigger this warning a single time per session
 let hasWriteSyncWarnHappened = false;
 
+export interface ICoreTerminal {
+  mouseStateService: IMouseStateService;
+  coreService: ICoreService;
+  optionsService: IOptionsService;
+  unicodeService: IUnicodeService;
+  buffers: IBufferSet;
+  options: Required<ITerminalOptions>;
+  registerCsiHandler(id: IFunctionIdentifier, callback: (params: IParams) => boolean | Promise<boolean>): IDisposable;
+  registerDcsHandler(id: IFunctionIdentifier, callback: (data: string, param: IParams) => boolean | Promise<boolean>): IDisposable;
+  registerEscHandler(id: IFunctionIdentifier, callback: () => boolean | Promise<boolean>): IDisposable;
+  registerOscHandler(ident: number, callback: (data: string) => boolean | Promise<boolean>): IDisposable;
+  registerApcHandler(id: IFunctionIdentifier, callback: (data: string) => boolean | Promise<boolean>): IDisposable;
+}
+
 export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
   protected readonly _instantiationService: IInstantiationService;
   protected readonly _bufferService: IBufferService;
@@ -116,6 +131,7 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
     this.mouseStateService = this._register(this._instantiationService.createInstance(MouseStateService));
     this._instantiationService.setService(IMouseStateService, this.mouseStateService);
     this.unicodeService = this._register(this._instantiationService.createInstance(UnicodeService));
+    this.unicodeService.register(new UnicodeV6());
     this._instantiationService.setService(IUnicodeService, this.unicodeService);
     this._charsetService = this._instantiationService.createInstance(CharsetService);
     this._instantiationService.setService(ICharsetService, this._charsetService);

src/common/InputHandler.test.ts

@@ -5,7 +5,8 @@
 
 import { assert } from 'chai';
 import { InputHandler } from './InputHandler';
-import { IBufferLine, IAttributeData, IColorEvent, ColorRequestType, SpecialColorIndex } from './Types';
+import { IColorEvent, ColorRequestType, SpecialColorIndex } from './Types';
+import { IAttributeData, IBufferLine } from './buffer/Types';
 import { DEFAULT_ATTR_DATA } from './buffer/BufferLine';
 import { CellData } from './buffer/CellData';
 import { Attributes, BgFlags, UnderlineStyle } from './buffer/Constants';
@@ -15,8 +16,10 @@ import { MockCoreService, MockBufferService, MockOptionsService, MockLogService,
 import { IBufferService, ICoreService, type IOscLinkService } from './services/Services';
 import { DEFAULT_OPTIONS } from './services/OptionsService';
 import { BufferService } from './services/BufferService';
+import { CharsetService } from './services/CharsetService';
 import { CoreService } from './services/CoreService';
 import { OscLinkService } from './services/OscLinkService';
+import { CHARSETS } from './data/Charsets';
 
 
 function getCursor(bufferService: IBufferService): number[] {
@@ -638,19 +641,38 @@ describe('InputHandler', () => {
   });
   describe('print', () => {
     it('should not cause an infinite loop (regression test)', () => {
-      const inputHandler = new TestInputHandler(
-        new MockBufferService(80, 30),
-        new MockCharsetService(),
-        new MockCoreService(),
-        new MockLogService(),
-        new MockOptionsService(),
-        new MockOscLinkService(),
-        new MockMouseStateService(),
-        new MockUnicodeService()
-      );
       const container = new Uint32Array(10);
       container[0] = 0x200B;
+      const lineCountBefore = bufferService.buffer.lines.length;
       inputHandler.print(container, 0, 1);
+      assert.strictEqual(bufferService.buffer.y, 0);
+      assert.strictEqual(bufferService.buffer.lines.length, lineCountBefore);
+    });
+    it('should join combining characters in a single print', async () => {
+      await inputHandler.parseP('e\u0301');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), 'e\u0301');
+      assert.strictEqual(bufferService.buffer.x, 1);
+    });
+    it('should join combining characters split across parse calls', async () => {
+      await inputHandler.parseP('e');
+      await inputHandler.parseP('\u0301');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), 'e\u0301');
+      assert.strictEqual(bufferService.buffer.x, 1);
+    });
+    it('should repeat preceding grapheme cluster via REP', async () => {
+      await inputHandler.parseP('e\u0301\x1b[2b');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), 'e\u0301e\u0301e\u0301');
+      assert.strictEqual(bufferService.buffer.x, 3);
+    });
+    it('should not repeat when REP has no preceding join state', async () => {
+      await inputHandler.parseP('\x1b[2b');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), '');
+      assert.strictEqual(bufferService.buffer.x, 0);
+    });
+    it('should not repeat after an intervening escape sequence', async () => {
+      await inputHandler.parseP('a\x1b[0m\x1b[2b');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), 'a');
+      assert.strictEqual(bufferService.buffer.x, 1);
     });
     it('should clear cells to the right on early wrap-around', async () => {
       bufferService.resize(5, 5);
@@ -667,6 +689,49 @@ describe('InputHandler', () => {
     });
   });
 
+  describe('ISO-2022 character sets', () => {
+    let charsetService: CharsetService;
+
+    beforeEach(() => {
+      charsetService = new CharsetService();
+      inputHandler = new TestInputHandler(
+        bufferService,
+        charsetService,
+        coreService,
+        new MockLogService(),
+        optionsService,
+        oscLinkService,
+        new MockMouseStateService(),
+        new MockUnicodeService()
+      );
+    });
+
+    it('should map G0 line drawing via ESC ( 0', async () => {
+      await inputHandler.parseP('\x1b(0q\x1b(Bq');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), '\u2500q');
+    });
+
+    it('should map G1 line drawing after ESC ) 0 and SO', async () => {
+      await inputHandler.parseP('\x1b)0\x0eq\x0f\x1b(Bq');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), '\u2500q');
+    });
+
+    it('should restore charset and glevel on ESC 7 / ESC 8', async () => {
+      await inputHandler.parseP('\x1b)0\x0e');
+      assert.strictEqual(charsetService.glevel, 1);
+      assert.strictEqual(charsetService.charset, CHARSETS['0']);
+      await inputHandler.parseP('\x1b7');
+      await inputHandler.parseP('\x0f\x1b(B');
+      assert.strictEqual(charsetService.glevel, 0);
+      assert.ok(charsetService.charset === undefined);
+      await inputHandler.parseP('\x1b8');
+      assert.strictEqual(charsetService.glevel, 1);
+      assert.strictEqual(charsetService.charset, CHARSETS['0']);
+      await inputHandler.parseP('q');
+      assert.strictEqual(bufferService.buffer.translateBufferLineToString(0, true), '\u2500');
+    });
+  });
+
   describe('alt screen', () => {
     let bufferService: IBufferService;
     let handler: TestInputHandler;
@@ -1181,6 +1246,19 @@ describe('InputHandler', () => {
       await inputHandler.parseP('\x1b[100;100H');
       assert.deepEqual(getCursor(bufferService), [9, 9]);
     });
+    it('cursor position (CUP) with DECOM and scroll margins', async () => {
+      await inputHandler.parseP('\x1b[?6h\x1b[2;3r\x1b[1;1H');
+      assert.deepEqual(getCursor(bufferService), [0, 1]);
+      await inputHandler.parseP('X');
+      assert.strictEqual(getLines(bufferService, 3)[1], 'X');
+      await inputHandler.parseP('\x1b[2;1H');
+      assert.deepEqual(getCursor(bufferService), [0, 2]);
+      await inputHandler.parseP('\x1b[10;10H');
+      assert.deepEqual(getCursor(bufferService), [9, 2]);
+      await inputHandler.parseP('\x1b[?6l');
+      await inputHandler.parseP('\x1b[2;1H');
+      assert.deepEqual(getCursor(bufferService), [0, 1]);
+    });
     it('horizontal position absolute (HPA)', async () => {
       await inputHandler.parseP('\x1b[`');
       assert.deepEqual(getCursor(bufferService), [0, 0]);
@@ -1240,7 +1318,7 @@ describe('InputHandler', () => {
       await inputHandler.parseP('\x1b[e');
       assert.deepEqual(getCursor(bufferService), [8, 5]);
     });
-    describe('should clamp cursor into addressible range', () => {
+    describe('should clamp cursor into addressable range', () => {
       it('CUF', async () => {
         bufferService.buffer.x = 10000;
         bufferService.buffer.y = 10000;

src/common/InputHandler.ts

@@ -4,7 +4,8 @@
  * @license MIT
  */
 
-import { IInputHandler, IAttributeData, IDisposable, IWindowOptions, IColorEvent, IParseStack, ColorIndex, ColorRequestType, SpecialColorIndex } from './Types';
+import { IInputHandler, IDisposable, IWindowOptions, IColorEvent, IParseStack, ColorIndex, ColorRequestType, SpecialColorIndex } from './Types';
+import { IAttributeData, IBuffer } from './buffer/Types';
 import { C0, C1 } from './data/EscapeSequences';
 import { CHARSETS, DEFAULT_CHARSET } from './data/Charsets';
 import { EscapeSequenceParser } from './parser/EscapeSequenceParser';
@@ -20,7 +21,6 @@ import { UnicodeService } from './services/UnicodeService';
 import { OscHandler } from './parser/OscParser';
 import { DcsHandler } from './parser/DcsParser';
 import { ApcHandler } from './parser/ApcParser';
-import { IBuffer } from './buffer/Types';
 import { parseColor } from './input/XParseColor';
 import { Emitter } from './Event';
 import { XTERM_VERSION } from './Version';
@@ -3065,7 +3065,7 @@ export class InputHandler extends Disposable implements IInputHandler {
       const idx = slots.shift() as string;
       const spec = slots.shift() as string;
       if (/^\d+$/.exec(idx)) {
-        const index = parseInt(idx);
+        const index = parseInt(idx, 10);
         if (isValidColorIndex(index)) {
           if (spec === '?') {
             event.push({ type: ColorRequestType.REPORT, index });
@@ -3228,7 +3228,7 @@ export class InputHandler extends Disposable implements IInputHandler {
     const slots = data.split(';');
     for (let i = 0; i < slots.length; ++i) {
       if (/^\d+$/.exec(slots[i])) {
-        const index = parseInt(slots[i]);
+        const index = parseInt(slots[i], 10);
         if (isValidColorIndex(index)) {
           event.push({ type: ColorRequestType.RESTORE, index });
         }

src/common/Platform.ts

@@ -41,10 +41,10 @@ export function getSafariVersion(): number {
   if (majorVersion === null || majorVersion.length < 2) {
     return 0;
   }
-  return parseInt(majorVersion[1]);
+  return parseInt(majorVersion[1], 10);
 }
 
-// Find the users platform. We use this to interpret the meta key
+// Find the user's platform. We use this to interpret the meta key
 // and ISO third level shifts.
 // http://stackoverflow.com/q/19877924/577598
 export const isMac = ['Macintosh', 'MacIntel', 'MacPPC', 'Mac68K'].includes(platform);

src/common/TaskQueue.ts

@@ -8,7 +8,7 @@ import type { ILogService } from './services/Services';
 interface ITaskQueue {
   /**
    * Adds a task to the queue which will run in a future idle callback.
-   * To avoid perceivable stalls on the mainthread, tasks with heavy workload
+   * To avoid perceivable stalls on the main thread, tasks with heavy workload
    * should split their work into smaller pieces and return `true` to get
    * called again until the work is done (on falsy return value).
    */

src/common/TestUtils.test.ts

@@ -6,9 +6,9 @@
 import { IBufferService, ICoreService, ILogService, IOptionsService, ITerminalOptions, IMouseStateService, ICharsetService, UnicodeCharProperties, UnicodeCharWidth, IUnicodeService, IUnicodeVersionProvider, LogLevelEnum, IDecorationService, IInternalDecoration, IOscLinkService, type IBufferResizeEvent } from './services/Services';
 import { UnicodeService } from './services/UnicodeService';
 import { DEFAULT_OPTIONS } from './services/OptionsService';
-import { IBufferSet, IBuffer } from './buffer/Types';
+import { IAttributeData, IBuffer, IBufferLine, IBufferSet, IExtendedAttrs } from './buffer/Types';
 import { BufferSet } from './buffer/BufferSet';
-import { IDecPrivateModes, ICoreMouseEvent, CoreMouseEventType, ICharset, IModes, IAttributeData, IOscLinkData, IDisposable, IBufferLine, IExtendedAttrs } from './Types';
+import { IDecPrivateModes, ICoreMouseEvent, CoreMouseEventType, ICharset, IModes, IOscLinkData, IDisposable } from './Types';
 import { UnicodeV6 } from './input/UnicodeV6';
 import { IDecorationOptions, IDecoration } from '@xterm/xterm';
 import { Emitter, type IEvent } from './Event';

src/common/Types.ts

@@ -3,26 +3,32 @@
  * @license MIT
  */
 
-import { IDeleteEvent, IInsertEvent } from './CircularList';
-import { UnderlineStyle } from './buffer/Constants';
-import { IBufferSet } from './buffer/Types';
-import { IParams } from './parser/Types';
-import { IMouseStateService, ICoreService, IOptionsService, IUnicodeService } from './services/Services';
 import { IFunctionIdentifier, ITerminalOptions as IPublicTerminalOptions } from '@xterm/xterm';
-import type { Emitter, IEvent } from './Event';
+import type { IEvent } from './Event';
 
-export interface ICoreTerminal {
-  mouseStateService: IMouseStateService;
-  coreService: ICoreService;
-  optionsService: IOptionsService;
-  unicodeService: IUnicodeService;
-  buffers: IBufferSet;
-  options: Required<ITerminalOptions>;
-  registerCsiHandler(id: IFunctionIdentifier, callback: (params: IParams) => boolean | Promise<boolean>): IDisposable;
-  registerDcsHandler(id: IFunctionIdentifier, callback: (data: string, param: IParams) => boolean | Promise<boolean>): IDisposable;
-  registerEscHandler(id: IFunctionIdentifier, callback: () => boolean | Promise<boolean>): IDisposable;
-  registerOscHandler(ident: number, callback: (data: string) => boolean | Promise<boolean>): IDisposable;
-  registerApcHandler(id: IFunctionIdentifier, callback: (data: string) => boolean | Promise<boolean>): IDisposable;
+/** sequence params serialized to js arrays */
+export type ParamsArray = (number | number[])[];
+
+/** Interface of Params storage class. */
+export interface IParams {
+  /** from ctor */
+  maxLength: number;
+  maxSubParamsLength: number;
+
+  /** param values and its length */
+  params: Int32Array;
+  length: number;
+
+  /** methods */
+  clone(): IParams;
+  toArray(): ParamsArray;
+  reset(): void;
+  resetZdm(): void;
+  addParam(value: number): void;
+  addSubParam(value: number): void;
+  hasSubParams(idx: number): boolean;
+  getSubParams(idx: number): Int32Array | null;
+  getSubParamsAll(): {[idx: number]: Int32Array};
 }
 
 export interface IDisposable {
@@ -62,28 +68,6 @@ export interface IScrollEvent {
   position: number;
 }
 
-export interface ICircularList<T> {
-  length: number;
-  maxLength: number;
-  isFull: boolean;
-
-  onDeleteEmitter: Emitter<IDeleteEvent>;
-  onDelete: IEvent<IDeleteEvent>;
-  onInsertEmitter: Emitter<IInsertEvent>;
-  onInsert: IEvent<IInsertEvent>;
-  onTrimEmitter: Emitter<number>;
-  onTrim: IEvent<number>;
-
-  get(index: number): T | undefined;
-  set(index: number, value: T): void;
-  push(value: T): void;
-  recycle(): T;
-  pop(): T | undefined;
-  splice(start: number, deleteCount: number, ...items: T[]): void;
-  trimStart(count: number): void;
-  shiftElements(start: number, count: number, offset: number): void;
-}
-
 export const enum KeyboardResultType {
   SEND_KEY,
   SELECT_ALL,
@@ -101,24 +85,12 @@ export interface ICharset {
   [key: string]: string | undefined;
 }
 
-export type CharData = [attr: number, char: string, width: number, code: number];
-
 export interface IColor {
   readonly css: string;
   readonly rgba: number; // 32-bit int with rgba in each byte
 }
 export type IColorRGB = [red: number, green: number, blue: number];
 
-export interface IExtendedAttrs {
-  ext: number;
-  underlineStyle: UnderlineStyle;
-  underlineColor: number;
-  underlineVariantOffset: number;
-  urlId: number;
-  clone(): IExtendedAttrs;
-  isEmpty(): boolean;
-}
-
 /**
  * Tracks the current hyperlink. Since these are treated as extended attirbutes, these get passed on
  * to the linkifier when anything is printed. Doing it this way ensures that even when the cursor
@@ -130,136 +102,6 @@ export interface IOscLinkData {
   uri: string;
 }
 
-/**
- * An object that represents all attributes of a cell.
- */
-export interface IAttributeData {
-  /**
-   * "fg" is a 32-bit unsigned integer that stores the foreground color of the cell in the 24 least
-   * significant bits and additional flags in the remaining 8 bits.
-   */
-  fg: number;
-  /**
-   * "bg" is a 32-bit unsigned integer that stores the background color of the cell in the 24 least
-   * significant bits and additional flags in the remaining 8 bits.
-   */
-  bg: number;
-  /**
-   * "extended", aka "ext", stores extended attributes beyond those available in fg and bg. This
-   * data is optional on a cell and encodes less common data.
-   */
-  extended: IExtendedAttrs;
-
-  clone(): IAttributeData;
-
-  // flags
-  isInverse(): number;
-  isBold(): number;
-  isUnderline(): number;
-  isBlink(): number;
-  isInvisible(): number;
-  isItalic(): number;
-  isDim(): number;
-  isStrikethrough(): number;
-  isProtected(): number;
-  isOverline(): number;
-
-  /**
-   * The color mode of the foreground color which determines how to decode {@link getFgColor},
-   * possible values include {@link Attributes.CM_DEFAULT}, {@link Attributes.CM_P16},
-   * {@link Attributes.CM_P256} and {@link Attributes.CM_RGB}.
-   */
-  getFgColorMode(): number;
-  /**
-   * The color mode of the background color which determines how to decode {@link getBgColor},
-   * possible values include {@link Attributes.CM_DEFAULT}, {@link Attributes.CM_P16},
-   * {@link Attributes.CM_P256} and {@link Attributes.CM_RGB}.
-   */
-  getBgColorMode(): number;
-  isFgRGB(): boolean;
-  isBgRGB(): boolean;
-  isFgPalette(): boolean;
-  isBgPalette(): boolean;
-  isFgDefault(): boolean;
-  isBgDefault(): boolean;
-  isAttributeDefault(): boolean;
-
-  /**
-   * Gets an integer representation of the foreground color, how to decode the color depends on the
-   * color mode {@link getFgColorMode}.
-   */
-  getFgColor(): number;
-  /**
-   * Gets an integer representation of the background color, how to decode the color depends on the
-   * color mode {@link getBgColorMode}.
-   */
-  getBgColor(): number;
-
-  // extended attrs
-  hasExtendedAttrs(): number;
-  updateExtended(): void;
-  getUnderlineColor(): number;
-  getUnderlineColorMode(): number;
-  isUnderlineColorRGB(): boolean;
-  isUnderlineColorPalette(): boolean;
-  isUnderlineColorDefault(): boolean;
-  getUnderlineStyle(): number;
-  getUnderlineVariantOffset(): number;
-}
-
-/** Cell data */
-export interface ICellData extends IAttributeData {
-  content: number;
-  combinedData: string;
-  isCombined(): number;
-  getWidth(): number;
-  getChars(): string;
-  getCode(): number;
-  setFromCharData(value: CharData): void;
-  getAsCharData(): CharData;
-}
-
-/**
- * Interface for a line in the terminal buffer.
- */
-export interface IBufferLine {
-  length: number;
-  isWrapped: boolean;
-  get(index: number): CharData;
-  set(index: number, value: CharData): void;
-  loadCell(index: number, cell: ICellData): ICellData;
-  setCell(index: number, cell: ICellData): void;
-  setCellFromCodepoint(index: number, codePoint: number, width: number, attrs: IAttributeData): void;
-  addCodepointToCell(index: number, codePoint: number, width: number): void;
-  insertCells(pos: number, n: number, ch: ICellData): void;
-  deleteCells(pos: number, n: number, fill: ICellData): void;
-  replaceCells(start: number, end: number, fill: ICellData, respectProtect?: boolean): void;
-  resize(cols: number, fill: ICellData): boolean;
-  cleanupMemory(): number;
-  fill(fillCellData: ICellData, respectProtect?: boolean): void;
-  copyFrom(line: IBufferLine): void;
-  clone(): IBufferLine;
-  getTrimmedLength(): number;
-  getNoBgTrimmedLength(): number;
-  translateToString(trimRight?: boolean, startCol?: number, endCol?: number, outColumns?: number[]): string;
-
-  /* direct access to cell attrs */
-  getWidth(index: number): number;
-  hasWidth(index: number): number;
-  getFg(index: number): number;
-  getBg(index: number): number;
-  hasContent(index: number): number;
-  getCodePoint(index: number): number;
-  isCombined(index: number): number;
-  getString(index: number): string;
-}
-
-export interface IMarker extends IDisposable {
-  readonly id: number;
-  readonly isDisposed: boolean;
-  readonly line: number;
-  onDispose: IEvent<void>;
-}
 export interface IModes {
   insertMode: boolean;
 }
@@ -339,7 +181,7 @@ export interface ICoreMouseEvent {
   x: number;
   y: number;
   /**
-   * Button the action occured. Due to restrictions of the tracking protocols
+   * Button the action occurred. Due to restrictions of the tracking protocols
    * it is not possible to report multiple buttons at once.
    * Wheel is treated as a button.
    * There are invalid combinations of buttons and actions possible

src/common/WindowsMode.test.ts

@@ -0,0 +1,54 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { DEFAULT_ATTR_DATA } from './buffer/BufferLine';
+import { updateWindowsModeWrappedState } from './WindowsMode';
+import { BufferService } from './services/BufferService';
+import { OptionsService } from './services/OptionsService';
+import { MockLogService } from './TestUtils.test';
+
+describe('WindowsMode', () => {
+  describe('updateWindowsModeWrappedState', () => {
+    it('should mark the next line wrapped when the previous line ends in a non-whitespace character', () => {
+      const bufferService = new BufferService(new OptionsService({ rows: 5, cols: 10 }), new MockLogService());
+      const buffer = bufferService.buffer;
+      const previousLine = buffer.lines.get(buffer.ybase)!;
+      for (let i = 0; i < bufferService.cols; i++) {
+        previousLine!.setCellFromCodepoint(i, 'a'.charCodeAt(0), 1, DEFAULT_ATTR_DATA);
+      }
+      buffer.y = 1;
+
+      updateWindowsModeWrappedState(bufferService);
+
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 1)!.isWrapped, true);
+    });
+
+    it('should not mark the next line wrapped when the previous line ends in whitespace', () => {
+      const bufferService = new BufferService(new OptionsService({ rows: 5, cols: 10 }), new MockLogService());
+      const buffer = bufferService.buffer;
+      const previousLine = buffer.lines.get(buffer.ybase)!;
+      for (let i = 0; i < bufferService.cols - 1; i++) {
+        previousLine!.setCellFromCodepoint(i, 'a'.charCodeAt(0), 1, DEFAULT_ATTR_DATA);
+      }
+      previousLine!.setCellFromCodepoint(bufferService.cols - 1, ' '.charCodeAt(0), 1, DEFAULT_ATTR_DATA);
+      buffer.y = 1;
+
+      updateWindowsModeWrappedState(bufferService);
+
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 1)!.isWrapped, false);
+    });
+
+    it('should not mark the next line wrapped when the previous line ends in a null cell', () => {
+      const bufferService = new BufferService(new OptionsService({ rows: 5, cols: 10 }), new MockLogService());
+      const buffer = bufferService.buffer;
+      buffer.y = 1;
+
+      updateWindowsModeWrappedState(bufferService);
+
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 1)!.isWrapped, false);
+    });
+  });
+});

src/common/buffer/AttributeData.ts

@@ -3,7 +3,8 @@
  * @license MIT
  */
 
-import { IAttributeData, IColorRGB, IExtendedAttrs } from '../Types';
+import { IColorRGB } from '../Types';
+import { IAttributeData, IExtendedAttrs } from './Types';
 import { Attributes, FgFlags, BgFlags, UnderlineStyle, ExtFlags } from './Constants';
 
 export class AttributeData implements IAttributeData {

src/common/buffer/Buffer.test.ts

@@ -233,6 +233,27 @@ describe('Buffer', () => {
           assert.equal(buffer.lines.length, INIT_ROWS + 10);
         });
       });
+
+      describe('Windows ConPTY', () => {
+        beforeEach(() => {
+          optionsService.options.windowsPty = { backend: 'conpty', buildNumber: 19000 };
+        });
+
+        it('should not adjust ybase or ydisp when growing rows', () => {
+          buffer.fillViewportRows();
+          for (let i = 0; i < 10; i++) {
+            buffer.lines.push(buffer.getBlankLine(DEFAULT_ATTR_DATA));
+          }
+          buffer.y = INIT_ROWS - 1;
+          buffer.ybase = 10;
+          buffer.ydisp = 10;
+          const linesBefore = buffer.lines.length;
+          buffer.resize(INIT_COLS, INIT_ROWS + 5);
+          assert.equal(buffer.ybase, 10);
+          assert.equal(buffer.ydisp, 10);
+          assert.equal(buffer.lines.length, linesBefore + 5);
+        });
+      });
     });
 
     describe('row and column increased', () => {
@@ -305,6 +326,71 @@ describe('Buffer', () => {
         assert.equal(buffer.lines.get(8)!.translateToString(), '     ');
         assert.equal(buffer.lines.get(9)!.translateToString(), '     ');
       });
+      it('should gate reflow on ConPTY buildNumber 21376', () => {
+        const prepareWrappedShrink = () => {
+          buffer.fillViewportRows();
+          buffer.resize(5, 10);
+          const firstLine = buffer.lines.get(0)!;
+          for (let i = 0; i < 5; i++) {
+            const code = 'a'.charCodeAt(0) + i;
+            firstLine.set(i, [0, String.fromCharCode(code), 1, code]);
+          }
+          buffer.y = 1;
+          buffer.resize(1, 10);
+        };
+
+        optionsService.options.windowsPty = { backend: 'conpty', buildNumber: 21375 };
+        prepareWrappedShrink();
+        assert.equal(buffer.lines.get(1)!.translateToString().trim(), '');
+
+        buffer = new TestBuffer(true, optionsService, bufferService, new MockLogService());
+        optionsService.options.windowsPty = { backend: 'conpty', buildNumber: 21376 };
+        prepareWrappedShrink();
+        assert.equal(buffer.lines.get(1)!.translateToString().trim(), 'b');
+        assert.ok(buffer.lines.get(1)!.isWrapped);
+      });
+      it('should unwrap lines on ConPTY builds with reflow support', () => {
+        optionsService.options.windowsPty = { backend: 'conpty', buildNumber: 21376 };
+        buffer.fillViewportRows();
+        buffer.resize(5, 10);
+        const firstLine = buffer.lines.get(0)!;
+        for (let i = 0; i < 5; i++) {
+          const code = 'a'.charCodeAt(0) + i;
+          firstLine.set(i, [0, String.fromCharCode(code), 1, code]);
+        }
+        buffer.y = 1;
+        buffer.resize(1, 10);
+        buffer.resize(5, 10);
+        assert.equal(buffer.lines.get(0)!.translateToString(), 'abcde');
+        assert.equal(buffer.lines.get(1)!.translateToString(), '     ');
+      });
+      it('should reflow wrapped lines containing the cursor when reflowCursorLine is enabled', () => {
+        optionsService.options.reflowCursorLine = true;
+        buffer.fillViewportRows();
+        buffer.resize(5, 10);
+        const firstLine = buffer.lines.get(0)!;
+        for (let i = 0; i < 5; i++) {
+          const code = 'a'.charCodeAt(0) + i;
+          firstLine.set(i, [0, String.fromCharCode(code), 1, code]);
+        }
+        buffer.resize(1, 10);
+        buffer.y = 2;
+        buffer.resize(5, 10);
+        assert.equal(buffer.lines.get(0)!.translateToString(), 'abcde');
+      });
+      it('should not reflow wrapped lines containing the cursor by default', () => {
+        buffer.fillViewportRows();
+        buffer.resize(5, 10);
+        const firstLine = buffer.lines.get(0)!;
+        for (let i = 0; i < 5; i++) {
+          const code = 'a'.charCodeAt(0) + i;
+          firstLine.set(i, [0, String.fromCharCode(code), 1, code]);
+        }
+        buffer.resize(1, 10);
+        buffer.y = 2;
+        buffer.resize(5, 10);
+        assert.notEqual(buffer.lines.get(0)!.translateToString(), 'abcde');
+      });
       it('should discard parts of wrapped lines that go out of the scrollback', () => {
         buffer.fillViewportRows();
         optionsService.options.scrollback = 1;

src/common/buffer/Buffer.ts

@@ -6,7 +6,8 @@
 import { CircularList, IInsertEvent } from '../CircularList';
 import { Disposable, toDisposable } from '../Lifecycle';
 import { IdleTaskQueue } from '../TaskQueue';
-import { IAttributeData, IBufferLine, ICellData, ICharset } from '../Types';
+import { ICharset } from '../Types';
+import { IAttributeData, IBuffer, IBufferLine, ICellData } from './Types';
 import { ExtendedAttrs } from './AttributeData';
 import { BufferLine, DEFAULT_ATTR_DATA } from './BufferLine';
 import { BufferLineStringCache } from './BufferLineStringCache';
@@ -14,7 +15,6 @@ import { getWrappedLineTrimmedLength, reflowLargerApplyNewLayout, reflowLargerCr
 import { CellData } from './CellData';
 import { NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, WHITESPACE_CELL_CHAR, WHITESPACE_CELL_CODE, WHITESPACE_CELL_WIDTH } from './Constants';
 import { Marker } from './Marker';
-import { IBuffer } from './Types';
 import { DEFAULT_CHARSET } from '../data/Charsets';
 import { IBufferService, ILogService, IOptionsService } from '../services/Services';
 
@@ -142,7 +142,7 @@ export class Buffer extends Disposable implements IBuffer {
   }
 
   /**
-   * Clears the buffer to it's initial state, discarding all previous data.
+   * Clears the buffer to its initial state, discarding all previous data.
    */
   public clear(): void {
     this._stringCache.clear();
@@ -197,7 +197,7 @@ export class Buffer extends Disposable implements IBuffer {
         for (let y = this._rows; y < newRows; y++) {
           if (this.lines.length < newRows + this.ybase) {
             if (this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined) {
-              // Just add the new missing rows on Windows as conpty reprints the screen with it's
+              // Just add the new missing rows on Windows as conpty reprints the screen with its
               // view of the world. Once a line enters scrollback for conpty it remains there
               this.lines.push(new BufferLine(this._stringCache, newCols, nullCell, false));
             } else {

src/common/buffer/BufferLine.test.ts

@@ -6,7 +6,7 @@ import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE, DEFAULT_ATTR, Content,
 import { BufferLine } from './BufferLine';
 import { BufferLineStringCache } from './BufferLineStringCache';
 import { CellData } from './CellData';
-import { CharData, IBufferLine, ICellData } from '../Types';
+import { CharData, IBufferLine, ICellData } from './Types';
 import { assert } from 'chai';
 import { AttributeData } from './AttributeData';
 import { createCellData, NULL_CELL_DATA, extendedAttributes } from '../TestUtils.test';

src/common/buffer/BufferLine.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { CharData, IAttributeData, IBufferLine, ICellData, IExtendedAttrs } from '../Types';
+import { CharData, IAttributeData, IBufferLine, ICellData, IExtendedAttrs } from './Types';
 import { AttributeData } from './AttributeData';
 import { CellData } from './CellData';
 import { Attributes, BgFlags, CHAR_DATA_ATTR_INDEX, CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, Content, NULL_CELL_CHAR, NULL_CELL_CODE, NULL_CELL_WIDTH, WHITESPACE_CELL_CHAR } from './Constants';
@@ -73,7 +73,9 @@ export interface IBufferLineStringCache {
  */
 export class BufferLine implements IBufferLine {
   protected _data: Uint32Array;
+  /** Sparse cache; only read when `IS_COMBINED_MASK` is set in `_data`. */
   protected _combined: {[index: number]: string} = {};
+  /** Sparse cache; only read when `HAS_EXTENDED` is set in `_data`. */
   protected _extendedAttrs: {[index: number]: IExtendedAttrs | undefined} = {};
   protected _stringCacheEntryRef: WeakRef<IBufferLineStringCacheEntry> | undefined;
   public length: number;
@@ -205,9 +207,15 @@ export class BufferLine implements IBufferLine {
     cell.bg = this._data[$startIndex + Cell.BG];
     if (cell.content & Content.IS_COMBINED_MASK) {
       cell.combinedData = this._combined[index];
+    } else {
+      cell.combinedData = '';
     }
     if (cell.bg & BgFlags.HAS_EXTENDED) {
       cell.extended = this._extendedAttrs[index]!;
+    } else {
+      // Do not mutate cell.extended in place: it may still reference this line's map entry from a
+      // prior loadCell into a reused CellData (e.g. $workCell during insert/delete).
+      cell.extended = DEFAULT_ATTR_DATA.extended.clone();
     }
     return cell;
   }
@@ -459,14 +467,7 @@ export class BufferLine implements IBufferLine {
       this._data.set(line._data);
     }
     this.length = line.length;
-    this._combined = {};
-    for (const el in line._combined) {
-      this._combined[el] = line._combined[el];
-    }
-    this._extendedAttrs = {};
-    for (const el in line._extendedAttrs) {
-      this._extendedAttrs[el] = line._extendedAttrs[el];
-    }
+    this._copySparseMapsFrom(line);
     this.isWrapped = line.isWrapped;
   }
 
@@ -475,12 +476,7 @@ export class BufferLine implements IBufferLine {
     const newLine = new BufferLine(this._stringCache, 0, undefined, false);
     newLine._data = new Uint32Array(this._data);
     newLine.length = this.length;
-    for (const el in this._combined) {
-      newLine._combined[el] = this._combined[el];
-    }
-    for (const el in this._extendedAttrs) {
-      newLine._extendedAttrs[el] = this._extendedAttrs[el];
-    }
+    newLine._copySparseMapsFrom(this);
     newLine.isWrapped = this.isWrapped;
     return newLine;
   }
@@ -511,27 +507,14 @@ export class BufferLine implements IBufferLine {
         for (let i = 0; i < Constants.CELL_INDICIES; i++) {
           this._data[(destCol + cell) * Constants.CELL_INDICIES + i] = srcData[(srcCol + cell) * Constants.CELL_INDICIES + i];
         }
-        if (srcData[(srcCol + cell) * Constants.CELL_INDICIES + Cell.BG] & BgFlags.HAS_EXTENDED) {
-          this._extendedAttrs[destCol + cell] = src._extendedAttrs[srcCol + cell];
-        }
+        this._copyCellMapsFrom(src, srcCol + cell, destCol + cell);
       }
     } else {
       for (let cell = 0; cell < length; cell++) {
         for (let i = 0; i < Constants.CELL_INDICIES; i++) {
           this._data[(destCol + cell) * Constants.CELL_INDICIES + i] = srcData[(srcCol + cell) * Constants.CELL_INDICIES + i];
         }
-        if (srcData[(srcCol + cell) * Constants.CELL_INDICIES + Cell.BG] & BgFlags.HAS_EXTENDED) {
-          this._extendedAttrs[destCol + cell] = src._extendedAttrs[srcCol + cell];
-        }
-      }
-    }
-
-    // Move any combined data over as needed, FIXME: repeat for extended attrs
-    const srcCombinedKeys = Object.keys(src._combined);
-    for (let i = 0; i < srcCombinedKeys.length; i++) {
-      const key = parseInt(srcCombinedKeys[i], 10);
-      if (key >= srcCol) {
-        this._combined[key - srcCol + destCol] = src._combined[key];
+        this._copyCellMapsFrom(src, srcCol + cell, destCol + cell);
       }
     }
   }
@@ -620,4 +603,24 @@ export class BufferLine implements IBufferLine {
       cacheEntry.isTrimmed = false;
     }
   }
+
+  /** Copy sparse map entries for a single cell when `_data` flags require them. */
+  private _copyCellMapsFrom(src: BufferLine, srcCol: number, destCol: number): void {
+    const srcStart = srcCol * Constants.CELL_INDICIES;
+    if (src._data[srcStart + Cell.CONTENT] & Content.IS_COMBINED_MASK) {
+      this._combined[destCol] = src._combined[srcCol];
+    }
+    if (src._data[srcStart + Cell.BG] & BgFlags.HAS_EXTENDED) {
+      this._extendedAttrs[destCol] = src._extendedAttrs[srcCol];
+    }
+  }
+
+  /** Rebuild sparse maps from another line, keyed only by `_data` flags. */
+  private _copySparseMapsFrom(line: BufferLine): void {
+    this._combined = {};
+    this._extendedAttrs = {};
+    for (let i = 0; i < line.length; i++) {
+      this._copyCellMapsFrom(line, i, i);
+    }
+  }
 }

src/common/buffer/BufferReflow.test.ts

@@ -3,10 +3,13 @@
  * @license MIT
  */
 import { assert } from 'chai';
+import { CircularList } from '../CircularList';
 import { BufferLine } from './BufferLine';
 import { BufferLineStringCache } from './BufferLineStringCache';
+import { CellData } from './CellData';
 import { NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE } from './Constants';
-import { reflowSmallerGetNewLineLengths } from './BufferReflow';
+import { reflowLargerGetLinesToRemove, reflowSmallerGetNewLineLengths } from './BufferReflow';
+import { IBufferLine } from './Types';
 
 const TEST_STRING_CACHE = new BufferLineStringCache();
 
@@ -93,4 +96,31 @@ describe('BufferReflow', () => {
       assert.deepEqual(reflowSmallerGetNewLineLengths([line], 4, 2), [2, 2], 'line: 汉, 语');
     });
   });
+  describe('reflowLargerGetLinesToRemove', () => {
+    const nullCell = CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
+
+    function createWrappedLines(chars: string): CircularList<IBufferLine> {
+      const lines = new CircularList<IBufferLine>(chars.length);
+      for (let i = 0; i < chars.length; i++) {
+        const line = new BufferLine(TEST_STRING_CACHE, 1);
+        line.set(0, [0, chars[i], 1, chars.charCodeAt(i)]);
+        line.isWrapped = i > 0;
+        lines.push(line);
+      }
+      return lines;
+    }
+
+    it('should skip reflow when the cursor is in a wrapped block and reflowCursorLine is false', () => {
+      const lines = createWrappedLines('abcde');
+      const skipped = reflowLargerGetLinesToRemove(lines, 1, 5, 2, nullCell, false);
+      const reflowed = reflowLargerGetLinesToRemove(lines, 1, 5, 2, nullCell, true);
+      assert.deepEqual(skipped, []);
+      assert.notDeepEqual(reflowed, []);
+    });
+
+    it('should reflow wrapped blocks when the cursor is outside the block', () => {
+      const lines = createWrappedLines('abcde');
+      assert.notDeepEqual(reflowLargerGetLinesToRemove(lines, 1, 5, 10, nullCell, false), []);
+    });
+  });
 });

src/common/buffer/BufferReflow.ts

@@ -5,7 +5,7 @@
 
 import { BufferLine } from './BufferLine';
 import { CircularList } from '../CircularList';
-import { IBufferLine, ICellData } from '../Types';
+import { IBufferLine, ICellData } from './Types';
 
 export interface INewLayoutResult {
   layout: number[];

src/common/buffer/BufferSet.ts

@@ -4,9 +4,8 @@
  */
 
 import { Disposable, MutableDisposable } from '../Lifecycle';
-import { IAttributeData } from '../Types';
 import { Buffer } from './Buffer';
-import { IBuffer, IBufferSet } from './Types';
+import { IAttributeData, IBuffer, IBufferSet } from './Types';
 import { IBufferService, ILogService, IOptionsService } from '../services/Services';
 import { Emitter } from '../Event';
 

src/common/buffer/CellData.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { CharData, ICellData, IExtendedAttrs } from '../Types';
+import { CharData, ICellData, IExtendedAttrs } from './Types';
 import { stringFromCodePoint } from '../input/TextDecoder';
 import { CHAR_DATA_CHAR_INDEX, CHAR_DATA_WIDTH_INDEX, CHAR_DATA_ATTR_INDEX, Content } from './Constants';
 import { AttributeData, ExtendedAttrs } from './AttributeData';

src/common/buffer/Constants.ts

@@ -24,7 +24,7 @@ export const NULL_CELL_CODE = 0;
 /**
  * Whitespace cell.
  * This is meant as a replacement for empty cells when needed
- * during rendering lines to preserve correct aligment.
+ * during rendering lines to preserve correct alignment.
  */
 export const WHITESPACE_CELL_CHAR = ' ';
 export const WHITESPACE_CELL_WIDTH = 1;
@@ -36,18 +36,18 @@ export const WHITESPACE_CELL_CODE = 32;
 export const enum Content {
   /**
    * bit 1..21    codepoint, max allowed in UTF32 is 0x10FFFF (21 bits taken)
-   *              read:   `codepoint = content & Content.codepointMask;`
-   *              write:  `content |= codepoint & Content.codepointMask;`
+   *              read:   `codepoint = content & Content.CODEPOINT_MASK;`
+   *              write:  `content |= codepoint & Content.CODEPOINT_MASK;`
    *                      shortcut if precondition `codepoint <= 0x10FFFF` is met:
    *                      `content |= codepoint;`
    */
   CODEPOINT_MASK = 0x1FFFFF,
 
   /**
-   * bit 22       flag indication whether a cell contains combined content
-   *              read:   `isCombined = content & Content.isCombined;`
-   *              set:    `content |= Content.isCombined;`
-   *              clear:  `content &= ~Content.isCombined;`
+   * bit 22       flag indicating whether a cell contains combined content
+   *              read:   `isCombined = content & Content.IS_COMBINED_MASK;`
+   *              set:    `content |= Content.IS_COMBINED_MASK;`
+   *              clear:  `content &= ~Content.IS_COMBINED_MASK;`
    */
   IS_COMBINED_MASK = 0x200000,  // 1 << 21
 
@@ -55,19 +55,19 @@ export const enum Content {
    * bit 1..22    mask to check whether a cell contains any string data
    *              we need to check for codepoint and isCombined bits to see
    *              whether a cell contains anything
-   *              read:   `isEmpty = !(content & Content.hasContent)`
+   *              read:   `isEmpty = !(content & Content.HAS_CONTENT_MASK)`
    */
   HAS_CONTENT_MASK = 0x3FFFFF,
 
   /**
    * bit 23..24   wcwidth value of cell, takes 2 bits (ranges from 0..2)
-   *              read:   `width = (content & Content.widthMask) >> Content.widthShift;`
-   *                      `hasWidth = content & Content.widthMask;`
+   *              read:   `width = (content & Content.WIDTH_MASK) >> Content.WIDTH_SHIFT;`
+   *                      `hasWidth = content & Content.WIDTH_MASK;`
    *                      as long as wcwidth is highest value in `content`:
-   *                      `width = content >> Content.widthShift;`
-   *              write:  `content |= (width << Content.widthShift) & Content.widthMask;`
+   *                      `width = content >> Content.WIDTH_SHIFT;`
+   *              write:  `content |= (width << Content.WIDTH_SHIFT) & Content.WIDTH_MASK;`
    *                      shortcut if precondition `0 <= width <= 3` is met:
-   *                      `content |= width << Content.widthShift;`
+   *                      `content |= width << Content.WIDTH_SHIFT;`
    */
   WIDTH_MASK = 0xC00000,   // 3 << 22
   WIDTH_SHIFT = 22

src/common/buffer/Marker.ts

@@ -3,9 +3,9 @@
  * @license MIT
  */
 
-import { IDisposable, IMarker } from '../Types';
+import { dispose, IDisposable } from '../Lifecycle';
+import { IMarker } from './Types';
 import { Emitter } from '../Event';
-import { dispose } from '../Lifecycle';
 
 export class Marker implements IMarker {
   private static _nextId = 1;
@@ -30,7 +30,7 @@ export class Marker implements IMarker {
     }
     this.isDisposed = true;
     this.line = -1;
-    // Emit before super.dispose such that dispose listeners get a change to react
+    // Emit before super.dispose such that dispose listeners get a chance to react
     this._onDispose.fire();
     dispose(this._disposables);
     this._disposables.length = 0;

src/common/buffer/Types.ts

@@ -3,12 +3,158 @@
  * @license MIT
  */
 
-import { IAttributeData, ICircularList, IBufferLine, ICellData, IMarker, ICharset, IDisposable } from '../Types';
 import type { IEvent } from '../Event';
+import type { ICircularList } from '../CircularList';
+import type { ICharset } from '../Types';
+import type { IDisposable } from '../Lifecycle';
+import type { UnderlineStyle } from './Constants';
 
 // BufferIndex denotes a position in the buffer: [rowIndex, colIndex]
 export type BufferIndex = [number, number];
 
+export type CharData = [attr: number, char: string, width: number, code: number];
+
+export interface IExtendedAttrs {
+  ext: number;
+  underlineStyle: UnderlineStyle;
+  underlineColor: number;
+  underlineVariantOffset: number;
+  urlId: number;
+  clone(): IExtendedAttrs;
+  isEmpty(): boolean;
+}
+
+/**
+ * An object that represents all attributes of a cell.
+ */
+export interface IAttributeData {
+  /**
+   * "fg" is a 32-bit unsigned integer that stores the foreground color of the cell in the 24 least
+   * significant bits and additional flags in the remaining 8 bits.
+   */
+  fg: number;
+  /**
+   * "bg" is a 32-bit unsigned integer that stores the background color of the cell in the 24 least
+   * significant bits and additional flags in the remaining 8 bits.
+   */
+  bg: number;
+  /**
+   * "extended", aka "ext", stores extended attributes beyond those available in fg and bg. This
+   * data is optional on a cell and encodes less common data.
+   */
+  extended: IExtendedAttrs;
+
+  clone(): IAttributeData;
+
+  // flags
+  isInverse(): number;
+  isBold(): number;
+  isUnderline(): number;
+  isBlink(): number;
+  isInvisible(): number;
+  isItalic(): number;
+  isDim(): number;
+  isStrikethrough(): number;
+  isProtected(): number;
+  isOverline(): number;
+
+  /**
+   * The color mode of the foreground color which determines how to decode {@link getFgColor},
+   * possible values include {@link Attributes.CM_DEFAULT}, {@link Attributes.CM_P16},
+   * {@link Attributes.CM_P256} and {@link Attributes.CM_RGB}.
+   */
+  getFgColorMode(): number;
+  /**
+   * The color mode of the background color which determines how to decode {@link getBgColor},
+   * possible values include {@link Attributes.CM_DEFAULT}, {@link Attributes.CM_P16},
+   * {@link Attributes.CM_P256} and {@link Attributes.CM_RGB}.
+   */
+  getBgColorMode(): number;
+  isFgRGB(): boolean;
+  isBgRGB(): boolean;
+  isFgPalette(): boolean;
+  isBgPalette(): boolean;
+  isFgDefault(): boolean;
+  isBgDefault(): boolean;
+  isAttributeDefault(): boolean;
+
+  /**
+   * Gets an integer representation of the foreground color, how to decode the color depends on the
+   * color mode {@link getFgColorMode}.
+   */
+  getFgColor(): number;
+  /**
+   * Gets an integer representation of the background color, how to decode the color depends on the
+   * color mode {@link getBgColorMode}.
+   */
+  getBgColor(): number;
+
+  // extended attrs
+  hasExtendedAttrs(): number;
+  updateExtended(): void;
+  getUnderlineColor(): number;
+  getUnderlineColorMode(): number;
+  isUnderlineColorRGB(): boolean;
+  isUnderlineColorPalette(): boolean;
+  isUnderlineColorDefault(): boolean;
+  getUnderlineStyle(): number;
+  getUnderlineVariantOffset(): number;
+}
+
+/** Cell data */
+export interface ICellData extends IAttributeData {
+  content: number;
+  combinedData: string;
+  isCombined(): number;
+  getWidth(): number;
+  getChars(): string;
+  getCode(): number;
+  setFromCharData(value: CharData): void;
+  getAsCharData(): CharData;
+}
+
+/**
+ * Interface for a line in the terminal buffer.
+ */
+export interface IBufferLine {
+  length: number;
+  isWrapped: boolean;
+  get(index: number): CharData;
+  set(index: number, value: CharData): void;
+  loadCell(index: number, cell: ICellData): ICellData;
+  setCell(index: number, cell: ICellData): void;
+  setCellFromCodepoint(index: number, codePoint: number, width: number, attrs: IAttributeData): void;
+  addCodepointToCell(index: number, codePoint: number, width: number): void;
+  insertCells(pos: number, n: number, ch: ICellData): void;
+  deleteCells(pos: number, n: number, fill: ICellData): void;
+  replaceCells(start: number, end: number, fill: ICellData, respectProtect?: boolean): void;
+  resize(cols: number, fill: ICellData): boolean;
+  cleanupMemory(): number;
+  fill(fillCellData: ICellData, respectProtect?: boolean): void;
+  copyFrom(line: IBufferLine): void;
+  clone(): IBufferLine;
+  getTrimmedLength(): number;
+  getNoBgTrimmedLength(): number;
+  translateToString(trimRight?: boolean, startCol?: number, endCol?: number, outColumns?: number[]): string;
+
+  /* direct access to cell attrs */
+  getWidth(index: number): number;
+  hasWidth(index: number): number;
+  getFg(index: number): number;
+  getBg(index: number): number;
+  hasContent(index: number): number;
+  getCodePoint(index: number): number;
+  isCombined(index: number): number;
+  getString(index: number): string;
+}
+
+export interface IMarker extends IDisposable {
+  readonly id: number;
+  readonly isDisposed: boolean;
+  readonly line: number;
+  onDispose: IEvent<void>;
+}
+
 export interface IBuffer {
   readonly lines: ICircularList<IBufferLine>;
   ydisp: number;

src/common/input/Keyboard.ts

@@ -46,7 +46,7 @@ export function evaluateKeyboardEvent(
     // Whether to cancel event propagation (NOTE: this may not be needed since the event is
     // canceled at the end of keyDown
     cancel: false,
-    // The new key even to emit
+    // The new key event to emit
     key: undefined
   };
   const modifiers = (ev.shiftKey ? 1 : 0) | (ev.altKey ? 2 : 0) | (ev.ctrlKey ? 4 : 0) | (ev.metaKey ? 8 : 0);

src/common/input/UnicodeV6.ts

@@ -132,6 +132,7 @@ export class UnicodeV6 implements IUnicodeVersionProvider {
   public charProperties(codepoint: number, preceding: UnicodeCharProperties): UnicodeCharProperties {
     let width = this.wcwidth(codepoint);
     let shouldJoin = width === 0 && preceding !== 0;
+    // HACK: Ideally this file would not depend on the service which uses it
     if (shouldJoin) {
       const oldWidth = UnicodeService.extractWidth(preceding);
       if (oldWidth === 0) {

src/common/input/WriteBuffer.ts

@@ -267,7 +267,7 @@ export class WriteBuffer extends Disposable {
          * this condition here, also the renderer has no way to spot nonsense updates either.
          * FIXME: A proper fix for this would track the FPS at the renderer entry level separately.
          *
-         * If favoring of FPS shows bad throughtput impact, use the following instead. It favors
+         * If favoring of FPS shows bad throughput impact, use the following instead. It favors
          * throughput by eval'ing `startTime` upfront pulling at least one more chunk into the
          * current microtask queue (executed before setTimeout).
          */

src/common/parser/ApcParser.test.ts

@@ -21,7 +21,7 @@ function identifier(id: IFunctionIdentifier): number {
       throw new Error('only one byte as prefix supported');
     }
     res = id.prefix.charCodeAt(0);
-    if (res && 0x3c > res || res > 0x3f) {
+    if (res < 0x3c || res > 0x3f) {
       throw new Error('prefix must be in range 0x3c .. 0x3f');
     }
   }
@@ -459,4 +459,29 @@ describe('ApcParser - async tests', () => {
       });
     });
   });
+  describe('reset', () => {
+    it('should abort active handlers with end(false) when reset during payload', () => {
+      const ident = identifier({ intermediates: '+', final: 'p' });
+      parser.registerHandler(ident, new TestHandler(reports, 'th'));
+      parser.start(ident);
+      let data = toUtf32('partial');
+      parser.put(data, 0, data.length);
+      parser.reset();
+      assert.deepEqual(reports, [
+        ['th', 'START'],
+        ['th', 'PUT', 'partial'],
+        ['th', 'END', false]
+      ]);
+      reports.length = 0;
+      parser.start(ident);
+      data = toUtf32('complete');
+      parser.put(data, 0, data.length);
+      parser.end(true);
+      assert.deepEqual(reports, [
+        ['th', 'START'],
+        ['th', 'PUT', 'complete'],
+        ['th', 'END', true]
+      ]);
+    });
+  });
 });

src/common/parser/DcsParser.test.ts

@@ -22,7 +22,7 @@ function identifier(id: IFunctionIdentifier): number {
       throw new Error('only one byte as prefix supported');
     }
     res = id.prefix.charCodeAt(0);
-    if (res && 0x3c > res || res > 0x3f) {
+    if (res < 0x3c || res > 0x3f) {
       throw new Error('prefix must be in range 0x3c .. 0x3f');
     }
   }
@@ -470,4 +470,30 @@ describe('DcsParser - async tests', () => {
       });
     });
   });
+  describe('reset', () => {
+    it('should abort active handlers with unhook(false) when reset during payload', () => {
+      const ident = identifier({ intermediates: '+', final: 'p' });
+      const params = Params.fromArray([1, 2, 3]);
+      parser.registerHandler(ident, new TestHandler(reports, 'th'));
+      parser.hook(ident, params);
+      let data = toUtf32('partial');
+      parser.put(data, 0, data.length);
+      parser.reset();
+      assert.deepEqual(reports, [
+        ['th', 'HOOK', [1, 2, 3]],
+        ['th', 'PUT', 'partial'],
+        ['th', 'UNHOOK', false]
+      ]);
+      reports.length = 0;
+      parser.hook(ident, params);
+      data = toUtf32('complete');
+      parser.put(data, 0, data.length);
+      parser.unhook(true);
+      assert.deepEqual(reports, [
+        ['th', 'HOOK', [1, 2, 3]],
+        ['th', 'PUT', 'complete'],
+        ['th', 'UNHOOK', true]
+      ]);
+    });
+  });
 });

src/common/parser/EscapeSequenceParser.test.ts

@@ -243,7 +243,7 @@ describe('EscapeSequenceParser', () => {
       p = new TestEscapeSequenceParser(tansitions);
       assert.deepEqual(p.transitions, tansitions);
     });
-    it('inital states', () => {
+    it('initial states', () => {
       assert.equal(parser.initialState, ParserState.GROUND);
       assert.equal(parser.currentState, ParserState.GROUND);
       assert.equal(parser.osc, '');
@@ -2177,6 +2177,38 @@ describe('EscapeSequenceParser - async', () => {
       parser.reset();
       await parseP(parser, INPUT); // does not throw anymore
     });
+    it('reset during async pause continues at next codepoint in chunk', async () => {
+      const localParser = new TestEscapeSequenceParser();
+      const localStack: any[] = [];
+      localParser.setPrintHandler((data, start, end) => {
+        let result = '';
+        for (let i = start; i < end; ++i) {
+          result += stringFromCodePoint(data[i]);
+        }
+        localStack.push(['PRINT', result]);
+      });
+      localParser.registerCsiHandler({ final: 'm' }, async params => {
+        localStack.push(['SGR', params.toArray()]);
+        return new Promise<boolean>(resolve => setTimeout(() => resolve(true), 0));
+      });
+      const data = '\x1b[1mXY';
+      const container = new Uint32Array(data.length);
+      const decoder = new StringToUtf32();
+      const len = decoder.decode(data, container);
+
+      assert.ok(localParser.parse(container, len) instanceof Promise);
+      localParser.reset();
+      assert.equal(localParser.parseStack.state, ParserStackType.RESET);
+
+      let prev: boolean | undefined = true;
+      let result: void | Promise<boolean> | undefined;
+      while (result = localParser.parse(container, len, prev)) {
+        prev = await result;
+      }
+
+      assert.deepEqual(localStack, [['SGR', [1]], ['PRINT', 'XY']]);
+      assert.equal(localParser.parseStack.state, ParserStackType.NONE);
+    });
     it('correct result on awaited parse call', async () => {
       await parseP(parser, INPUT);
       assert.deepEqual(callstack, RESULT);

src/common/parser/EscapeSequenceParser.ts

@@ -18,7 +18,7 @@ import { ApcParser } from './ApcParser';
 // @vt: #Y   ESC   CSI   "Control Sequence Introducer"   "ESC ["   "Start of a CSI sequence."
 // @vt: #Y   ESC   OSC   "Operating System Command"      "ESC ]"   "Start of an OSC sequence."
 // @vt: #Y   ESC   DCS   "Device Control String"         "ESC P"   "Start of a DCS sequence."
-// @vt: #Y   ESC   ST    "String Terminator"             "ESC \"   "Terminator used for string type sequences."
+// @vt: #Y   ESC   ST    "String Terminator"             "ESC \\"  "Terminator used for string type sequences."
 // @vt: #Y   ESC   PM    "Privacy Message"               "ESC ^"   "Start of a privacy message."
 // @vt: #Y   ESC   APC   "Application Program Command"   "ESC _"   "Start of an APC sequence."
 // @vt: #Y   C1    CSI   "Control Sequence Introducer"   "\x9B"    "Start of a CSI sequence."
@@ -243,7 +243,7 @@ export const VT500_TRANSITION_TABLE = (function (): TransitionTable {
  *
  * This parser is currently hardcoded to operate in ZDM (Zero Default Mode)
  * as suggested by the original parser, thus empty parameters are set to 0.
- * This this is not in line with the latest ECMA-48 specification
+ * This is not in line with the latest ECMA-48 specification
  * (ZDM was part of the early specs and got completely removed later on).
  *
  * Other than the original parser from vt100.net this parser supports
@@ -342,7 +342,7 @@ export class EscapeSequenceParser extends Disposable implements IEscapeSequenceP
         throw new Error('only one byte as prefix supported');
       }
       res = id.prefix.charCodeAt(0);
-      if (res && 0x3c > res || res > 0x3f) {
+      if (res < 0x3c || res > 0x3f) {
         throw new Error('prefix must be in range 0x3c .. 0x3f');
       }
     }

src/common/parser/OscParser.test.ts

@@ -464,4 +464,28 @@ describe('OscParser - async tests', () => {
       });
     });
   });
+  describe('reset', () => {
+    it('should abort active handlers with end(false) when reset during payload', () => {
+      parser.registerHandler(1234, new TestHandler(1234, reports, 'th'));
+      parser.start();
+      let data = toUtf32('1234;partial');
+      parser.put(data, 0, data.length);
+      parser.reset();
+      assert.deepEqual(reports, [
+        ['th', 1234, 'START'],
+        ['th', 1234, 'PUT', 'partial'],
+        ['th', 1234, 'END', false]
+      ]);
+      reports.length = 0;
+      parser.start();
+      data = toUtf32('1234;complete');
+      parser.put(data, 0, data.length);
+      parser.end(true);
+      assert.deepEqual(reports, [
+        ['th', 1234, 'START'],
+        ['th', 1234, 'PUT', 'complete'],
+        ['th', 1234, 'END', true]
+      ]);
+    });
+  });
 });

src/common/parser/Params.test.ts

@@ -199,13 +199,13 @@ describe('Params', () => {
     it('reject params lesser -1', () => {
       const params = new Params();
       params.addParam(-1);
-      assert.throws(() => params.addParam(-2), 'values lesser than -1 are not allowed');
+      assert.throws(() => params.addParam(-2), 'values less than -1 are not allowed');
     });
     it('reject subparams lesser -1', () => {
       const params = new Params();
       params.addParam(-1);
       params.addSubParam(-1);
-      assert.throws(() => params.addSubParam(-2), 'values lesser than -1 are not allowed');
+      assert.throws(() => params.addSubParam(-2), 'values less than -1 are not allowed');
       assert.deepEqual(params.toArray(), [-1, [-1]]);
     });
     it('clamp parsed params', () => {

src/common/parser/Params.ts

@@ -162,7 +162,7 @@ export class Params implements IParams {
       return;
     }
     if (value < -1) {
-      throw new Error('values lesser than -1 are not allowed');
+      throw new Error('values less than -1 are not allowed');
     }
     this._subParamsIdx[this.length] = this._subParamsLength << 8 | this._subParamsLength;
     this.params[this.length++] = value > Constants.MAX_VALUE ? Constants.MAX_VALUE : value;
@@ -172,7 +172,7 @@ export class Params implements IParams {
    * Add a sub parameter value.
    * The sub parameter is automatically associated with the last parameter value.
    * Thus it is not possible to add a subparameter without any parameter added yet.
-   * `Params` only stores up to `subParamsLength` sub parameters, any later
+   * `Params` only stores up to `maxSubParamsLength` sub parameters, any later
    * sub parameter will be ignored.
    */
   public addSubParam(value: number): void {
@@ -185,7 +185,7 @@ export class Params implements IParams {
       return;
     }
     if (value < -1) {
-      throw new Error('values lesser than -1 are not allowed');
+      throw new Error('values less than -1 are not allowed');
     }
     this._subParams[this._subParamsLength++] = value > Constants.MAX_VALUE ? Constants.MAX_VALUE : value;
     this._subParamsIdx[this.length - 1]++;

src/common/parser/Types.ts

@@ -3,12 +3,10 @@
  * @license MIT
  */
 
-import { IDisposable } from '../Types';
+import { IDisposable, IParams, ParamsArray } from '../Types';
 import { ParserState } from './Constants';
 
-
-/** sequence params serialized to js arrays */
-export type ParamsArray = (number | number[])[];
+export type { IParams, ParamsArray };
 
 /** Params constructor type. */
 export interface IParamsConstructor {
@@ -18,28 +16,6 @@ export interface IParamsConstructor {
   fromArray(values: ParamsArray): IParams;
 }
 
-/** Interface of Params storage class. */
-export interface IParams {
-  /** from ctor */
-  maxLength: number;
-  maxSubParamsLength: number;
-
-  /** param values and its length */
-  params: Int32Array;
-  length: number;
-
-  /** methods */
-  clone(): IParams;
-  toArray(): ParamsArray;
-  reset(): void;
-  resetZdm(): void;
-  addParam(value: number): void;
-  addSubParam(value: number): void;
-  hasSubParams(idx: number): boolean;
-  getSubParams(idx: number): Int32Array | null;
-  getSubParamsAll(): {[idx: number]: Int32Array};
-}
-
 /**
  * Internal state of EscapeSequenceParser.
  * Used as argument of the error handler to allow
@@ -258,8 +234,8 @@ export interface IApcParser extends ISubParser<IApcHandler, ApcFallbackHandlerTy
 
 /**
  * Interface to denote a specific ESC, CSI or DCS handler slot.
- * The values are used to create an integer respresentation during handler
- * regristation before passed to the subparsers as `ident`.
+ * The values are used to create an integer representation during handler
+ * registration before passed to the subparsers as `ident`.
  * The integer translation is made to allow a faster handler access
  * in `EscapeSequenceParser.parse`.
  */

src/common/public/BufferLineApiView.ts

@@ -4,7 +4,7 @@
  */
 
 import { CellData } from '../buffer/CellData';
-import { IBufferLine, ICellData } from '../Types';
+import { IBufferLine, ICellData } from '../buffer/Types';
 import { IBufferCell as IBufferCellApi, IBufferLine as IBufferLineApi } from '@xterm/xterm';
 
 export class BufferLineApiView implements IBufferLineApi {

src/common/public/BufferNamespaceApi.ts

@@ -5,7 +5,7 @@
 
 import { IBuffer as IBufferApi, IBufferNamespace as IBufferNamespaceApi } from '@xterm/xterm';
 import { BufferApiView } from './BufferApiView';
-import { ICoreTerminal } from '../Types';
+import { ICoreTerminal } from '../CoreTerminal';
 import { Disposable } from '../Lifecycle';
 import { Emitter } from '../Event';
 

src/common/public/ParserApi.ts

@@ -5,7 +5,7 @@
 
 import { IParams } from '../parser/Types';
 import { IDisposable, IFunctionIdentifier, IParser } from '@xterm/xterm';
-import { ICoreTerminal } from '../Types';
+import { ICoreTerminal } from '../CoreTerminal';
 
 export class ParserApi implements IParser {
   constructor(private _core: ICoreTerminal) { }

src/common/public/UnicodeApi.ts

@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { ICoreTerminal } from '../Types';
+import { ICoreTerminal } from '../CoreTerminal';
 import { IUnicodeHandling, IUnicodeVersionProvider } from '@xterm/xterm';
 
 export class UnicodeApi implements IUnicodeHandling {

src/common/services/BufferService.test.ts

@@ -0,0 +1,137 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { AttributeData } from '../buffer/AttributeData';
+import { BufferService } from './BufferService';
+import { OptionsService } from './OptionsService';
+import { MockLogService } from '../TestUtils.test';
+
+describe('BufferService', () => {
+  describe('scroll', () => {
+    const eraseAttr = new AttributeData();
+
+    it('should decrement ydisp when the buffer is full and the user has scrolled up', () => {
+      const optionsService = new OptionsService({ rows: 3, cols: 10, scrollback: 2 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+
+      while (!buffer.lines.isFull) {
+        bufferService.scroll(eraseAttr);
+      }
+      assert.strictEqual(buffer.lines.length, 5);
+
+      bufferService.isUserScrolling = true;
+      buffer.ydisp = 2;
+      const ybaseBefore = buffer.ybase;
+
+      bufferService.scroll(eraseAttr);
+
+      assert.strictEqual(buffer.ybase, ybaseBefore);
+      assert.strictEqual(buffer.ydisp, 1);
+    });
+
+    it('should not advance ydisp with ybase while the user has scrolled up and the buffer is not full', () => {
+      const optionsService = new OptionsService({ rows: 3, cols: 10, scrollback: 2 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+
+      bufferService.isUserScrolling = true;
+      buffer.ydisp = 0;
+      const ybaseBefore = buffer.ybase;
+
+      bufferService.scroll(eraseAttr);
+
+      assert.strictEqual(buffer.ybase, ybaseBefore + 1);
+      assert.strictEqual(buffer.ydisp, 0);
+    });
+
+    it('should follow ybase with ydisp when the user is not scrolling', () => {
+      const optionsService = new OptionsService({ rows: 3, cols: 10, scrollback: 2 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+
+      while (!buffer.lines.isFull) {
+        bufferService.scroll(eraseAttr);
+      }
+
+      bufferService.isUserScrolling = false;
+      bufferService.scroll(eraseAttr);
+
+      assert.strictEqual(buffer.ydisp, buffer.ybase);
+    });
+
+    it('should scroll within DECSTBM margins without affecting lines outside the region', () => {
+      const optionsService = new OptionsService({ rows: 5, cols: 10, scrollback: 10 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+
+      const markRow = (row: number, ch: string) => {
+        buffer.lines.get(buffer.ybase + row)!.setCellFromCodepoint(0, ch.charCodeAt(0), 1, eraseAttr);
+      };
+      markRow(0, 'A');
+      markRow(1, 'B');
+      markRow(2, 'C');
+      markRow(3, 'D');
+      markRow(4, 'E');
+      buffer.scrollTop = 1;
+      buffer.scrollBottom = 3;
+
+      bufferService.scroll(eraseAttr);
+
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 0)!.translateToString().trim(), 'A');
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 1)!.translateToString().trim(), 'C');
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 2)!.translateToString().trim(), 'D');
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 3)!.translateToString(true).trim(), '');
+      assert.strictEqual(buffer.lines.get(buffer.ybase + 4)!.translateToString().trim(), 'E');
+    });
+  });
+
+  describe('scrollLines', () => {
+    it('should move ydisp and set isUserScrolling when scrolling up', () => {
+      const optionsService = new OptionsService({ rows: 10, cols: 80, scrollback: 10 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+      buffer.ybase = 5;
+      buffer.ydisp = 5;
+
+      let scrollEvent: number | undefined;
+      bufferService.onScroll(e => { scrollEvent = e; });
+
+      bufferService.scrollLines(-2);
+
+      assert.strictEqual(buffer.ydisp, 3);
+      assert.strictEqual(bufferService.isUserScrolling, true);
+      assert.strictEqual(scrollEvent, 3);
+    });
+
+    it('should not scroll above the top of the buffer', () => {
+      const optionsService = new OptionsService({ rows: 10, cols: 80, scrollback: 10 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+      buffer.ybase = 5;
+      buffer.ydisp = 0;
+
+      bufferService.scrollLines(-1);
+
+      assert.strictEqual(buffer.ydisp, 0);
+      assert.strictEqual(bufferService.isUserScrolling, false);
+    });
+
+    it('should clear isUserScrolling when scrolling to the bottom', () => {
+      const optionsService = new OptionsService({ rows: 10, cols: 80, scrollback: 10 });
+      const bufferService = new BufferService(optionsService, new MockLogService());
+      const buffer = bufferService.buffer;
+      buffer.ybase = 5;
+      buffer.ydisp = 2;
+      bufferService.isUserScrolling = true;
+
+      bufferService.scrollLines(10);
+
+      assert.strictEqual(buffer.ydisp, 5);
+      assert.strictEqual(bufferService.isUserScrolling, false);
+    });
+  });
+});

src/common/services/BufferService.ts

@@ -4,9 +4,8 @@
  */
 
 import { Disposable } from '../Lifecycle';
-import { IAttributeData, IBufferLine } from '../Types';
+import { IAttributeData, IBuffer, IBufferLine, IBufferSet } from '../buffer/Types';
 import { BufferSet } from '../buffer/BufferSet';
-import { IBuffer, IBufferSet } from '../buffer/Types';
 import { IBufferService, ILogService, IOptionsService, type IBufferResizeEvent } from './Services';
 import { Emitter } from '../Event';
 

src/common/services/CharsetService.test.ts

@@ -0,0 +1,43 @@
+/**
+ * Copyright (c) 2026 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { CHARSETS } from '../data/Charsets';
+import { CharsetService } from './CharsetService';
+
+describe('CharsetService', () => {
+  let service: CharsetService;
+
+  beforeEach(() => {
+    service = new CharsetService();
+  });
+
+  it('should not update active charset when designating an inactive glevel', () => {
+    service.setgCharset(1, CHARSETS['0']);
+    assert.strictEqual(service.glevel, 0);
+    assert.ok(service.charset === undefined);
+  });
+
+  it('should expose the designated charset after setgLevel', () => {
+    service.setgCharset(1, CHARSETS['0']);
+    service.setgLevel(1);
+    assert.strictEqual(service.charset, CHARSETS['0']);
+  });
+
+  it('should update active charset when designating the current glevel', () => {
+    service.setgLevel(1);
+    service.setgCharset(1, CHARSETS['0']);
+    assert.strictEqual(service.charset, CHARSETS['0']);
+  });
+
+  it('should reset glevel, charsets, and active charset', () => {
+    service.setgCharset(1, CHARSETS['0']);
+    service.setgLevel(1);
+    service.reset();
+    assert.strictEqual(service.glevel, 0);
+    assert.deepEqual(service.charsets, []);
+    assert.ok(service.charset === undefined);
+  });
+});

src/common/services/DecorationService.test.ts

@@ -5,7 +5,7 @@
 
 import { assert } from 'chai';
 import { DecorationLineCache, DecorationService } from './DecorationService';
-import { IMarker } from '../Types';
+import { IMarker } from '../buffer/Types';
 import { Disposable } from '../Lifecycle';
 import { Emitter } from '../Event';
 import { MockLogService, MockBufferService, MockOptionsService } from '../TestUtils.test';

src/common/services/DecorationService.ts

@@ -3,13 +3,13 @@
  * @license MIT
  */
 
-import type { IDeleteEvent, IInsertEvent } from '../CircularList';
+import type { ICircularList, IDeleteEvent, IInsertEvent } from '../CircularList';
 import { MicrotaskTimer } from '../Async';
 import { css } from '../Color';
 import { Disposable, DisposableStore, MutableDisposable, toDisposable } from '../Lifecycle';
 import { IBufferService, IDecorationService, IInternalDecoration, ILogService } from './Services';
 import { SortedList } from '../SortedList';
-import { IColor, ICircularList } from '../Types';
+import { IColor } from '../Types';
 import { IDecoration, IDecorationOptions, IMarker } from '@xterm/xterm';
 import { Emitter } from '../Event';
 

src/common/services/InstantiationService.ts

@@ -9,8 +9,8 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { IInstantiationService, IServiceIdentifier } from './Services';
-import { getServiceDependencies } from './ServiceRegistry';
+import { IInstantiationService } from './Services';
+import { IServiceIdentifier, getServiceDependencies } from './ServiceRegistry';
 
 export class ServiceCollection {
 

src/common/services/OscLinkService.ts

@@ -3,7 +3,8 @@
  * @license MIT
  */
 import { IBufferService, IOscLinkService } from './Services';
-import { IMarker, IOscLinkData } from '../Types';
+import { IOscLinkData } from '../Types';
+import { IMarker } from '../buffer/Types';
 
 export class OscLinkService implements IOscLinkService {
   public serviceBrand: any;

src/common/services/ServiceRegistry.ts

@@ -9,7 +9,11 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { IServiceIdentifier } from './Services';
+export interface IServiceIdentifier<T> {
+  (...args: any[]): void;
+  type: T;
+  _id: string;
+}
 
 const enum Constants {
   DI_TARGET = 'di$target',

src/common/services/Services.ts

@@ -4,9 +4,9 @@
  */
 
 import type { IDecoration, IDecorationOptions, ILinkHandler, ILogger, IWindowsPty, IOverviewRulerOptions } from '@xterm/xterm';
-import { CoreMouseEncoding, CoreMouseEventType, CursorInactiveStyle, CursorStyle, IAttributeData, ICharset, IColor, ICoreMouseEvent, ICoreMouseProtocol, IDecPrivateModes, IDisposable, IKittyKeyboardState, IModes, IOscLinkData, IWindowOptions } from '../Types';
-import { IBuffer, IBufferSet } from '../buffer/Types';
-import { createDecorator } from './ServiceRegistry';
+import { CoreMouseEncoding, CoreMouseEventType, CursorInactiveStyle, CursorStyle, ICharset, IColor, ICoreMouseEvent, ICoreMouseProtocol, IDecPrivateModes, IDisposable, IKittyKeyboardState, IModes, IOscLinkData, IWindowOptions } from '../Types';
+import { IAttributeData, IBuffer, IBufferSet } from '../buffer/Types';
+import { createDecorator, IServiceIdentifier } from './ServiceRegistry';
 import type { Emitter, IEvent } from '../Event';
 
 export const IBufferService = createDecorator<IBufferService>('BufferService');
@@ -119,12 +119,6 @@ export interface ICharsetService {
   setgCharset(g: number, charset: ICharset | undefined): void;
 }
 
-export interface IServiceIdentifier<T> {
-  (...args: any[]): void;
-  type: T;
-  _id: string;
-}
-
 export interface IBrandedService {
   serviceBrand: undefined;
 }
@@ -350,13 +344,13 @@ export type UnicodeCharWidth = 0 | 1 | 2;
 export const IUnicodeService = createDecorator<IUnicodeService>('UnicodeService');
 export interface IUnicodeService {
   serviceBrand: undefined;
-  /** Register an Unicode version provider. */
+  /** Register a Unicode version provider. */
   register(provider: IUnicodeVersionProvider): void;
   /** Registered Unicode versions. */
   readonly versions: string[];
   /** Currently active version. */
   activeVersion: string;
-  /** Event triggered, when activate version changed. */
+  /** Event triggered when the active version changes. */
   readonly onChange: IEvent<string>;
 
   /**