Support reporting XTVERSION

Fixes #5342

src/common/InputHandler.test.ts

@@ -1582,6 +1582,28 @@ describe('InputHandler', () => {
       assert.equal(bufferService.cols, 132);
     });
   });
+  describe('XTVERSION (CSI > q, CSI > 0 q)', () => {
+    it('should report xterm.js version', async () => {
+      const stack: string[] = [];
+      coreService.onData(data => stack.push(data));
+      await inputHandler.parseP('\x1b[>q');
+      assert.strictEqual(stack.length, 1);
+      assert.ok(stack[0].match(/^\x1bP>\|xterm\.js\(\d+\.\d+\.\d+(-beta\.\d+)?\)\x1b\\/));
+    });
+    it('should report xterm.js version for CSI > 0 q', async () => {
+      const stack: string[] = [];
+      coreService.onData(data => stack.push(data));
+      await inputHandler.parseP('\x1b[>0q');
+      assert.strictEqual(stack.length, 1);
+      assert.ok(stack[0].match(/^\x1bP>\|xterm\.js\(\d+\.\d+\.\d+(-beta\.\d+)?\)\x1b\\/));
+    });
+    it('should not report for CSI > 1 q', async () => {
+      const stack: string[] = [];
+      coreService.onData(data => stack.push(data));
+      await inputHandler.parseP('\x1b[>1q');
+      assert.strictEqual(stack.length, 0);
+    });
+  });
   describe('should correctly reset cells taken by wide chars', () => {
     beforeEach(async () => {
       bufferService.resize(10, 5);

src/common/InputHandler.ts

@@ -22,6 +22,7 @@ import { DcsHandler } from 'common/parser/DcsParser';
 import { IBuffer } from 'common/buffer/Types';
 import { parseColor } from 'common/input/XParseColor';
 import { Emitter } from 'vs/base/common/event';
+import { XTERM_VERSION } from 'common/Version';
 
 /**
  * Map collect to glevel. Used in `selectCharset`.
@@ -256,6 +257,7 @@ export class InputHandler extends Disposable implements IInputHandler {
     this._parser.registerCsiHandler({ final: 'n' }, params => this.deviceStatus(params));
     this._parser.registerCsiHandler({ prefix: '?', final: 'n' }, params => this.deviceStatusPrivate(params));
     this._parser.registerCsiHandler({ intermediates: '!', final: 'p' }, params => this.softReset(params));
+    this._parser.registerCsiHandler({ prefix: '>', final: 'q' }, params => this.sendXtVersion(params));
     this._parser.registerCsiHandler({ intermediates: ' ', final: 'q' }, params => this.setCursorStyle(params));
     this._parser.registerCsiHandler({ final: 'r' }, params => this.setScrollRegion(params));
     this._parser.registerCsiHandler({ final: 's' }, params => this.saveCursor(params));
@@ -1721,6 +1723,22 @@ export class InputHandler extends Disposable implements IInputHandler {
     return true;
   }
 
+  /**
+   * CSI > Ps q
+   *   Ps = 0  => Report xterm name and version (XTVERSION).
+   *
+   * The response is a DCS sequence identifying the version: DCS > | text ST
+   *
+   * @vt: #Y CSI XTVERSION "Report Xterm Version" "CSI > q" "Report the terminal name and version."
+   */
+  public sendXtVersion(params: IParams): boolean {
+    if (params.params[0] > 0) {
+      return true;
+    }
+    this._coreService.triggerDataEvent(`${C0.ESC}P>|xterm.js(${XTERM_VERSION})${C0.ESC}\\`);
+    return true;
+  }
+
   /**
    * Evaluate if the current terminal is the given argument.
    * @param term The terminal name to evaluate

src/common/Version.ts

@@ -0,0 +1,9 @@
+/**
+ * Copyright (c) 2025 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+/**
+ * The xterm.js version. This is updated by the publish script from package.json.
+ */
+export const XTERM_VERSION = '6.0.0';