Add oxlint import/no-cycle and break existing src/common cycles

Enable oxlint's import/no-cycle rule (import plugin) so circular module
dependencies are caught in CI, similar to eslint-plugin-import/no-cycle
and biome no-import-cycles discussed in the issue.

Relocate shared types and dependencies to remove cycles under src/common:

- Types.ts: host IInsertEvent, IDeleteEvent, IParams, UnderlineStyle,
  IBuffer, and IBufferSet; drop imports from CircularList, buffer/Types,
  parser/Types, and Services
- CoreTerminal.ts: define and export ICoreTerminal
- ServiceRegistry.ts: define IServiceIdentifier (break Services registry loop)
- UnicodeService: stop constructing UnicodeV6; CoreTerminal registers the
  default v6 provider after service creation
- buffer/Types.ts and parser/Types.ts: re-export moved types for callers

Fixes https://github.com/xtermjs/xterm.js/issues/5897

Co-authored-by: Cursor <cursoragent@cursor.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": [
     {

src/browser/Types.ts

@@ -3,7 +3,8 @@
  * @license MIT
  */
 
-import { CharData, IColor, ICoreTerminal, ITerminalOptions } from '../common/Types';
+import { CharData, IColor, ITerminalOptions } from '../common/Types';
+import { ICoreTerminal } from '../common/CoreTerminal';
 import { IBuffer } from '../common/buffer/Types';
 import { IDisposable, IRenderDimensions as IRenderDimensionsApi, Terminal as ITerminalApi } from '@xterm/xterm';
 import { channels, css } from '../common/Color';

src/common/CircularList.ts

@@ -3,19 +3,11 @@
  * @license MIT
  */
 
-import { ICircularList } from './Types';
+import { ICircularList, IDeleteEvent, IInsertEvent } from './Types';
 import { Disposable } from './Lifecycle';
 import { Emitter } from './Event';
 
-export interface IInsertEvent {
-  index: number;
-  amount: number;
-}
-
-export interface IDeleteEvent {
-  index: number;
-  amount: number;
-}
+export type { IDeleteEvent, IInsertEvent } from './Types';
 
 /**
  * Represents a circular list; a list with a maximum size that wraps around when push is called,

src/common/CoreTerminal.ts

@@ -21,18 +21,19 @@
  *   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, IAttributeData, IScrollEvent, ITerminalOptions, IParams } from './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 { IFunctionIdentifier } from './parser/Types';
 import { IBufferSet } from './buffer/Types';
 import { InputHandler } from './InputHandler';
 import { WriteBuffer } from './input/WriteBuffer';
@@ -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/Types.ts

@@ -3,26 +3,51 @@
  * @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';
 
-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 interface IInsertEvent {
+  index: number;
+  amount: number;
+}
+
+export interface IDeleteEvent {
+  index: number;
+  amount: number;
+}
+
+/** 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 const enum UnderlineStyle {
+  NONE = 0,
+  SINGLE = 1,
+  DOUBLE = 2,
+  CURLY = 3,
+  DOTTED = 4,
+  DASHED = 5
 }
 
 export interface IDisposable {
@@ -260,6 +285,53 @@ export interface IMarker extends IDisposable {
   readonly line: number;
   onDispose: IEvent<void>;
 }
+
+export interface IBuffer {
+  readonly lines: ICircularList<IBufferLine>;
+  ydisp: number;
+  ybase: number;
+  y: number;
+  x: number;
+  tabs: any;
+  scrollBottom: number;
+  scrollTop: number;
+  hasScrollback: boolean;
+  savedY: number;
+  savedX: number;
+  savedCharset: ICharset | undefined;
+  savedCharsets: (ICharset | undefined)[];
+  savedGlevel: number;
+  savedOriginMode: boolean;
+  savedWraparoundMode: boolean;
+  savedCurAttrData: IAttributeData;
+  isCursorInViewport: boolean;
+  markers: IMarker[];
+  translateBufferLineToString(lineIndex: number, trimRight: boolean, startCol?: number, endCol?: number): string;
+  getWrappedRangeForLine(y: number): { first: number, last: number };
+  nextStop(x?: number): number;
+  prevStop(x?: number): number;
+  getBlankLine(attr: IAttributeData, isWrapped?: boolean): IBufferLine;
+  getNullCell(attr?: IAttributeData): ICellData;
+  getWhitespaceCell(attr?: IAttributeData): ICellData;
+  addMarker(y: number): IMarker;
+  clearMarkers(y: number): void;
+  clearAllMarkers(): void;
+}
+
+export interface IBufferSet extends IDisposable {
+  alt: IBuffer;
+  normal: IBuffer;
+  active: IBuffer;
+
+  onBufferActivate: IEvent<{ activeBuffer: IBuffer, inactiveBuffer: IBuffer }>;
+
+  activateNormalBuffer(): void;
+  activateAltBuffer(fillAttr?: IAttributeData): void;
+  reset(): void;
+  resize(newCols: number, newRows: number): void;
+  setupTabStops(i?: number): void;
+}
+
 export interface IModes {
   insertMode: boolean;
 }

src/common/buffer/Constants.ts

@@ -147,11 +147,4 @@ export const enum ExtFlags {
   VARIANT_OFFSET = 0xE0000000
 }
 
-export const enum UnderlineStyle {
-  NONE = 0,
-  SINGLE = 1,
-  DOUBLE = 2,
-  CURLY = 3,
-  DOTTED = 4,
-  DASHED = 5
-}
+export { UnderlineStyle } from '../Types';

src/common/buffer/Types.ts

@@ -3,54 +3,7 @@
  * @license MIT
  */
 
-import { IAttributeData, ICircularList, IBufferLine, ICellData, IMarker, ICharset, IDisposable } from '../Types';
-import type { IEvent } from '../Event';
+export type { IBuffer, IBufferSet } from '../Types';
 
 // BufferIndex denotes a position in the buffer: [rowIndex, colIndex]
 export type BufferIndex = [number, number];
-
-export interface IBuffer {
-  readonly lines: ICircularList<IBufferLine>;
-  ydisp: number;
-  ybase: number;
-  y: number;
-  x: number;
-  tabs: any;
-  scrollBottom: number;
-  scrollTop: number;
-  hasScrollback: boolean;
-  savedY: number;
-  savedX: number;
-  savedCharset: ICharset | undefined;
-  savedCharsets: (ICharset | undefined)[];
-  savedGlevel: number;
-  savedOriginMode: boolean;
-  savedWraparoundMode: boolean;
-  savedCurAttrData: IAttributeData;
-  isCursorInViewport: boolean;
-  markers: IMarker[];
-  translateBufferLineToString(lineIndex: number, trimRight: boolean, startCol?: number, endCol?: number): string;
-  getWrappedRangeForLine(y: number): { first: number, last: number };
-  nextStop(x?: number): number;
-  prevStop(x?: number): number;
-  getBlankLine(attr: IAttributeData, isWrapped?: boolean): IBufferLine;
-  getNullCell(attr?: IAttributeData): ICellData;
-  getWhitespaceCell(attr?: IAttributeData): ICellData;
-  addMarker(y: number): IMarker;
-  clearMarkers(y: number): void;
-  clearAllMarkers(): void;
-}
-
-export interface IBufferSet extends IDisposable {
-  alt: IBuffer;
-  normal: IBuffer;
-  active: IBuffer;
-
-  onBufferActivate: IEvent<{ activeBuffer: IBuffer, inactiveBuffer: IBuffer }>;
-
-  activateNormalBuffer(): void;
-  activateAltBuffer(fillAttr?: IAttributeData): void;
-  reset(): void;
-  resize(newCols: number, newRows: number): void;
-  setupTabStops(i?: number): void;
-}

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/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

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/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/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

@@ -6,7 +6,7 @@
 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 { 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;
 }

src/common/services/UnicodeService.test.ts

@@ -4,6 +4,7 @@
  */
 
 import { assert } from 'chai';
+import { UnicodeV6 } from '../input/UnicodeV6';
 import { UnicodeService } from './UnicodeService';
 import { IUnicodeVersionProvider } from './Services';
 
@@ -21,6 +22,7 @@ describe('unicode provider', () => {
   let us: UnicodeService;
   beforeEach(() => {
     us = new UnicodeService();
+    us.register(new UnicodeV6());
   });
   it('default to V6', () => {
     assert.equal(us.activeVersion, '6');

src/common/services/UnicodeService.ts

@@ -3,7 +3,6 @@
  * @license MIT
  */
 
-import { UnicodeV6 } from '../input/UnicodeV6';
 import { IUnicodeService, IUnicodeVersionProvider, UnicodeCharProperties, UnicodeCharWidth } from './Services';
 import { Emitter } from '../Event';
 
@@ -12,7 +11,7 @@ export class UnicodeService implements IUnicodeService {
 
   private _providers: {[key: string]: IUnicodeVersionProvider} = Object.create(null);
   private _active: string = '';
-  private _activeProvider: IUnicodeVersionProvider;
+  private _activeProvider!: IUnicodeVersionProvider;
 
   private readonly _onChange = new Emitter<string>();
   public readonly onChange = this._onChange.event;
@@ -30,13 +29,6 @@ export class UnicodeService implements IUnicodeService {
     return ((state & 0xffffff) << 3) | ((width & 3) << 1) | (shouldJoin?1:0);
   }
 
-  constructor() {
-    const defaultProvider = new UnicodeV6();
-    this.register(defaultProvider);
-    this._active = defaultProvider.version;
-    this._activeProvider = defaultProvider;
-  }
-
   public dispose(): void {
     this._onChange.dispose();
   }
@@ -60,6 +52,9 @@ export class UnicodeService implements IUnicodeService {
 
   public register(provider: IUnicodeVersionProvider): void {
     this._providers[provider.version] = provider;
+    if (!this._active) {
+      this.activeVersion = provider.version;
+    }
   }
 
   /**

test/playwright/TestUtils.ts

@@ -7,7 +7,8 @@ import { Browser, JSHandle, Page } from '@playwright/test';
 import { deepStrictEqual, strictEqual } from 'assert';
 import type { IRenderDimensions as IRenderDimensionsInternal } from '../../src/browser/renderer/shared/Types';
 import type { IRenderService } from '../../src/browser/services/Services';
-import type { ICoreTerminal, IDisposable, IMarker } from '../../src/common/Types';
+import type { IDisposable, IMarker } from '../../src/common/Types';
+import type { ICoreTerminal } from '../../src/common/CoreTerminal';
 import * as playwright from '@playwright/test';
 import { IBuffer, IBufferCell, IBufferLine, IBufferNamespace, IBufferRange, IDecoration, IDecorationOptions, IModes, IRenderDimensions, ITerminalInitOnlyOptions, ITerminalOptions, Terminal } from '@xterm/xterm';