Add more granular windowsPty option

See microsoft/vscode#134448

demo/client.ts

@@ -240,7 +240,11 @@ function createTerminal(): void {
   const isWindows = ['Windows', 'Win16', 'Win32', 'WinCE'].indexOf(navigator.platform) >= 0;
   term = new Terminal({
     allowProposedApi: true,
-    windowsMode: isWindows,
+    windowsPty: isWindows ? {
+      // In a real scenario, these values should be verified on the backend
+      backend: 'conpty',
+      buildNumber: 22621
+    } : undefined,
     fontFamily: '"Fira Code", courier-new, courier, monospace, "Powerline Extra Symbols"',
     theme: xtermjsTheme
   } as ITerminalOptions);

src/common/CoreTerminal.ts

@@ -57,7 +57,7 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
 
   protected _inputHandler: InputHandler;
   private _writeBuffer: WriteBuffer;
-  private _windowsMode: IDisposable | undefined;
+  private _windowsWrappingHeuristics: IDisposable | undefined;
 
   private readonly _onBinary = this.register(new EventEmitter<string>());
   public readonly onBinary = this._onBinary.event;
@@ -146,8 +146,8 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
     this.register(forwardEvent(this._writeBuffer.onWriteParsed, this._onWriteParsed));
 
     this.register(toDisposable(() => {
-      this._windowsMode?.dispose();
-      this._windowsMode = undefined;
+      this._windowsWrappingHeuristics?.dispose();
+      this._windowsWrappingHeuristics = undefined;
     }));
   }
 
@@ -250,8 +250,13 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
   }
 
   protected _setup(): void {
-    if (this.optionsService.rawOptions.windowsMode) {
-      this._enableWindowsMode();
+    const windowsPty = this.optionsService.rawOptions.windowsPty;
+    if (windowsPty) {
+      if (windowsPty.buildNumber && windowsPty.backend === 'conpty' && windowsPty.buildNumber < 21376) {
+        this._enableWindowsWrappingHeuristics();
+      }
+    } else if (this.optionsService.rawOptions.windowsMode) {
+      this._enableWindowsWrappingHeuristics();
     }
   }
 
@@ -265,28 +270,26 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
 
   private _handleWindowsModeOptionChange(value: boolean): void {
     if (value) {
-      this._enableWindowsMode();
+      this._enableWindowsWrappingHeuristics();
     } else {
-      this._windowsMode?.dispose();
-      this._windowsMode = undefined;
+      this._windowsWrappingHeuristics?.dispose();
+      this._windowsWrappingHeuristics = undefined;
     }
   }
 
-  protected _enableWindowsMode(): void {
-    if (!this._windowsMode) {
+  protected _enableWindowsWrappingHeuristics(): void {
+    if (!this._windowsWrappingHeuristics) {
       const disposables: IDisposable[] = [];
       disposables.push(this.onLineFeed(updateWindowsModeWrappedState.bind(null, this._bufferService)));
       disposables.push(this.registerCsiHandler({ final: 'H' }, () => {
         updateWindowsModeWrappedState(this._bufferService);
         return false;
       }));
-      this._windowsMode = {
-        dispose: () => {
-          for (const d of disposables) {
-            d.dispose();
-          }
+      this._windowsWrappingHeuristics = toDisposable(() => {
+        for (const d of disposables) {
+          d.dispose();
         }
-      };
+      });
     }
   }
 }

src/common/buffer/Buffer.ts

@@ -177,7 +177,7 @@ export class Buffer implements IBuffer {
       if (this._rows < newRows) {
         for (let y = this._rows; y < newRows; y++) {
           if (this.lines.length < newRows + this.ybase) {
-            if (this._optionsService.rawOptions.windowsMode) {
+            if (this._optionsService.rawOptions.windowsMode || 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
               // view of the world. Once a line enters scrollback for conpty it remains there
               this.lines.push(new BufferLine(newCols, nullCell));
@@ -290,6 +290,10 @@ export class Buffer implements IBuffer {
   }
 
   private get _isReflowEnabled(): boolean {
+    const windowsPty = this._optionsService.rawOptions.windowsPty;
+    if (windowsPty && windowsPty.buildNumber) {
+      return this._hasScrollback && windowsPty.backend === 'conpty' && windowsPty.buildNumber >= 21376;
+    }
     return this._hasScrollback && !this._optionsService.rawOptions.windowsMode;
   }
 

src/common/services/OptionsService.ts

@@ -43,6 +43,7 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   rightClickSelectsWord: isMac,
   windowOptions: {},
   windowsMode: false,
+  windowsPty: {},
   wordSeparator: ' ()[]{}\',"`',
   altClickMovesCursor: true,
   convertEol: false,

src/common/services/Services.ts

@@ -7,7 +7,7 @@ import { IEvent, IEventEmitter } from 'common/EventEmitter';
 import { IBuffer, IBufferSet } from 'common/buffer/Types';
 import { IDecPrivateModes, ICoreMouseEvent, CoreMouseEncoding, ICoreMouseProtocol, CoreMouseEventType, ICharset, IWindowOptions, IModes, IAttributeData, ScrollSource, IDisposable, IColor, CursorStyle, IOscLinkData } from 'common/Types';
 import { createDecorator } from 'common/services/ServiceRegistry';
-import { IDecorationOptions, IDecoration, ILinkHandler } from 'xterm';
+import { IDecorationOptions, IDecoration, ILinkHandler, IWindowsPty } from 'xterm';
 
 export const IBufferService = createDecorator<IBufferService>('BufferService');
 export interface IBufferService {
@@ -242,6 +242,7 @@ export interface ITerminalOptions {
   tabStopWidth?: number;
   theme?: ITheme;
   windowsMode?: boolean;
+  windowsPty?: IWindowsPty;
   windowOptions?: IWindowOptions;
   wordSeparator?: string;
   overviewRulerWidth?: number;

typings/xterm-headless.d.ts

@@ -183,9 +183,34 @@ declare module 'xterm-headless' {
      * - Reflow is disabled.
      * - Lines are assumed to be wrapped if the last character of the line is
      *   not whitespace.
+     *
+     * When using conpty on Windows 11 version >= 21376, it is recommended to
+     * disable this because native text wrapping sequences are output correctly
+     * thanks to https://github.com/microsoft/terminal/issues/405
+     *
+     * @deprecated Use {@link windowsPty}. This value will be ignored if
+     * windowsPty is set.
      */
     windowsMode?: boolean;
 
+    /**
+     * Compatibility information when the pty is known to be hosted on Windows.
+     * Setting this will turn on certain heuristics/workarounds depending on the
+     * values:
+     *
+     * - `if (!!windowsCompat)`
+     *   - When increasing the rows in the terminal, the amount increased into
+     *     the scrollback. This is done because ConPTY does not behave like
+     *     expect scrollback to come back into the viewport, instead it makes
+     *     empty rows at of the viewport. Not having this behavior can result in
+     *     missing data as the rows get replaced.
+     * - `if !(backend === 'conpty' && buildNumber >= 21376)`
+     *   - Reflow is disabled
+     *   - Lines are assumed to be wrapped if the last character of the line is
+     *     not whitespace.
+     */
+    windowsPty?: IWindowsPty;
+
     /**
      * A string containing all characters that are considered word separated by the
      * double click to select work logic.
@@ -265,6 +290,20 @@ declare module 'xterm-headless' {
     extendedAnsi?: string[];
   }
 
+  /**
+   * Pty information for Windows.
+   */
+  export interface IWindowsPty {
+    /**
+     * What pty emulation backend is being used.
+     */
+    backend?: 'conpty' | 'winpty';
+    /**
+     * The Windows build version (eg. 19045)
+     */
+    buildNumber?: number;
+  }
+
   /**
    * An object that can be disposed via a dispose function.
    */

typings/xterm.d.ts

@@ -238,9 +238,30 @@ declare module 'xterm' {
      * When using conpty on Windows 11 version >= 21376, it is recommended to
      * disable this because native text wrapping sequences are output correctly
      * thanks to https://github.com/microsoft/terminal/issues/405
+     *
+     * @deprecated Use {@link windowsPty}. This value will be ignored if
+     * windowsPty is set.
      */
     windowsMode?: boolean;
 
+    /**
+     * Compatibility information when the pty is known to be hosted on Windows.
+     * Setting this will turn on certain heuristics/workarounds depending on the
+     * values:
+     *
+     * - `if (backend !== undefined || buildNumber !== undefined)`
+     *   - When increasing the rows in the terminal, the amount increased into
+     *     the scrollback. This is done because ConPTY does not behave like
+     *     expect scrollback to come back into the viewport, instead it makes
+     *     empty rows at of the viewport. Not having this behavior can result in
+     *     missing data as the rows get replaced.
+     * - `if !(backend === 'conpty' && buildNumber >= 21376)`
+     *   - Reflow is disabled
+     *   - Lines are assumed to be wrapped if the last character of the line is
+     *     not whitespace.
+     */
+    windowsPty?: IWindowsPty;
+
     /**
      * A string containing all characters that are considered word separated by the
      * double click to select work logic.
@@ -330,6 +351,20 @@ declare module 'xterm' {
     extendedAnsi?: string[];
   }
 
+  /**
+   * Pty information for Windows.
+   */
+  export interface IWindowsPty {
+    /**
+     * What pty emulation backend is being used.
+     */
+    backend?: 'conpty' | 'winpty';
+    /**
+     * The Windows build version (eg. 19045)
+     */
+    buildNumber?: number;
+  }
+
   /**
    * An object that can be disposed via a dispose function.
    */