Guard terminal resize/dispose race against xterm.js dimension getters

src/vs/workbench/contrib/terminal/browser/terminalInstance.ts

@@ -816,14 +816,23 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 			() => this._isVisible,
 			() => xterm,
 			async (cols, rows) => {
+				if (this.isDisposed) {
+					return;
+				}
 				xterm.resize(cols, rows);
 				await this._updatePtyDimensions(xterm.raw);
 			},
 			async (cols) => {
+				if (this.isDisposed) {
+					return;
+				}
 				xterm.resize(cols, xterm.raw.rows);
 				await this._updatePtyDimensions(xterm.raw);
 			},
 			async (rows) => {
+				if (this.isDisposed) {
+					return;
+				}
 				xterm.resize(xterm.raw.cols, rows);
 				await this._updatePtyDimensions(xterm.raw);
 			}
@@ -2047,8 +2056,22 @@ export class TerminalInstance extends Disposable implements ITerminalInstance {
 	}
 
 	private async _updatePtyDimensions(rawXterm: XTermTerminal): Promise<void> {
-		const pixelWidth = rawXterm.dimensions?.css.canvas.width;
-		const pixelHeight = rawXterm.dimensions?.css.canvas.height;
+		if (this.isDisposed) {
+			return;
+		}
+		// `rawXterm.dimensions` proxies to xterm.js' RenderService which throws
+		// `Cannot read properties of undefined (reading 'dimensions')` if the
+		// renderer was disposed between scheduling and invocation (debounced or
+		// idle resize callbacks racing with terminal teardown). Guard against
+		// that here so the optional chaining short-circuits to undefined.
+		let pixelWidth: number | undefined;
+		let pixelHeight: number | undefined;
+		try {
+			pixelWidth = rawXterm.dimensions?.css.canvas.width;
+			pixelHeight = rawXterm.dimensions?.css.canvas.height;
+		} catch {
+			// Renderer disposed mid-flight; fall through with undefined dimensions.
+		}
 		const roundedPixelWidth = pixelWidth ? Math.round(pixelWidth) : undefined;
 		const roundedPixelHeight = pixelHeight ? Math.round(pixelHeight) : undefined;
 		await this._processManager.setDimensions(rawXterm.cols, rawXterm.rows, undefined, roundedPixelWidth, roundedPixelHeight);

src/vs/workbench/contrib/terminal/browser/terminalResizeDebouncer.ts

@@ -33,6 +33,9 @@ export class TerminalResizeDebouncer extends Disposable {
 	}
 
 	async resize(cols: number, rows: number, immediate: boolean): Promise<void> {
+		if (this._store.isDisposed) {
+			return;
+		}
 		this._latestX = cols;
 		this._latestY = rows;
 
@@ -49,12 +52,18 @@ export class TerminalResizeDebouncer extends Disposable {
 		if (win && !this._isVisible()) {
 			if (!this._resizeXJob.value) {
 				this._resizeXJob.value = runWhenWindowIdle(win, async () => {
+					if (this._store.isDisposed) {
+						return;
+					}
 					this._resizeXCallback(this._latestX);
 					this._resizeXJob.clear();
 				});
 			}
 			if (!this._resizeYJob.value) {
 				this._resizeYJob.value = runWhenWindowIdle(win, async () => {
+					if (this._store.isDisposed) {
+						return;
+					}
 					this._resizeYCallback(this._latestY);
 					this._resizeYJob.clear();
 				});
@@ -70,6 +79,9 @@ export class TerminalResizeDebouncer extends Disposable {
 	}
 
 	flush(): void {
+		if (this._store.isDisposed) {
+			return;
+		}
 		if (this._resizeXJob.value || this._resizeYJob.value) {
 			this._resizeXJob.clear();
 			this._resizeYJob.clear();
@@ -79,6 +91,12 @@ export class TerminalResizeDebouncer extends Disposable {
 
 	@debounce(100)
 	private _debounceResizeX(cols: number) {
+		// The @debounce decorator schedules a setTimeout that is not tied to the
+		// disposable store, so this can fire after the terminal/xterm renderer is
+		// disposed. Bail out to avoid throwing from xterm.js dimension getters.
+		if (this._store.isDisposed) {
+			return;
+		}
 		this._resizeXCallback(cols);
 	}
 }