Fix Android WebView keyboard input not forwarding onData immediately

src/browser/CoreBrowserTerminal.ts

@@ -854,6 +854,10 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     const shouldIgnoreComposition = this.browser.isMac && this.options.macOptionIsMeta && event.altKey;
 
     if (!shouldIgnoreComposition && !this._compositionHelper!.keydown(event)) {
+      // Reset _keyDownSeen when composition handles the keydown (e.g. keyCode 229 on
+      // Android). The keydown did not produce any data, so the subsequent input event
+      // must be allowed through to _inputEvent() to forward the IME text.
+      this._keyDownSeen = false;
       if (this.options.scrollOnUserInput && this.buffer.ybase !== this.buffer.ydisp) {
         this.scrollToBottom(true);
       }
@@ -1037,6 +1041,9 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
       // The key was handled so clear the dead key state, otherwise certain keystrokes like arrow
       // keys could be ignored
       this._unprocessedDeadKey = false;
+      // Cancel any pending composition send when the input event handles the committed text.
+      // This prevents double-sending when _finalizeComposition's setTimeout fires.
+      this._compositionHelper?.cancelPendingComposition();
 
       const text = ev.data;
       this.coreService.triggerDataEvent(text, true);

src/browser/TestUtils.test.ts

@@ -360,6 +360,9 @@ export class MockCompositionHelper implements ICompositionHelper {
   public keydown(ev: KeyboardEvent): boolean {
     return true;
   }
+  public cancelPendingComposition(): void {
+    // no-op
+  }
 }
 
 export class MockCoreBrowserService implements ICoreBrowserService {

src/browser/Types.ts

@@ -44,6 +44,7 @@ export interface ICompositionHelper {
   compositionend(): void;
   updateCompositionElements(dontRecurse?: boolean): void;
   keydown(ev: KeyboardEvent): boolean;
+  cancelPendingComposition(): void;
 }
 
 export interface IBrowser {

src/browser/input/CompositionHelper.ts

@@ -203,6 +203,15 @@ export class CompositionHelper {
     }
   }
 
+  /**
+   * Cancel any pending composition send. This is called from _inputEvent when the
+   * IME committed text is handled via the input event, preventing a double-send from
+   * the _finalizeComposition timeout.
+   */
+  public cancelPendingComposition(): void {
+    this._isSendingComposition = false;
+  }
+
   /**
    * Apply any changes made to the textarea after the current event chain is allowed to complete.
    * This should be called when not currently composing but a keydown event with the "composition