Fix urgent interrupt input cleanup

components/terminal/runtime/createXTermRuntime.ts

@@ -79,6 +79,7 @@ import {
   createTerminalInterruptTrace,
   logTerminalInterruptTrace,
 } from "./terminalInterruptDiagnostics";
+import { clearTerminalInputStateForInterrupt } from "./terminalInterruptInputState";
 import { getFlowControllerForTerm } from "./terminalSessionAttachment";
 import { prioritizeTerminalInput } from "./terminalOutputPipeline";
 import {
@@ -822,6 +823,11 @@ export const createXTermRuntime = (ctx: CreateXTermRuntimeContext): XTermRuntime
         logTerminalInterruptTrace("renderer-keydown-send", interruptTrace, {
           priority,
         });
+        clearTerminalInputStateForInterrupt({
+          commandBufferRef: ctx.commandBufferRef,
+          serialLineBufferRef: ctx.serialLineBufferRef,
+          onAutocompleteInput: ctx.onAutocompleteInput,
+        });
         if (ctx.terminalBackend.interruptSession) {
           ctx.terminalBackend.interruptSession(id, interruptTrace);
         } else {

components/terminal/runtime/terminalInterruptInputState.test.ts

@@ -0,0 +1,29 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { clearTerminalInputStateForInterrupt } from "./terminalInterruptInputState";
+
+test("interrupt input state clearing matches the normal Ctrl+C input bookkeeping", () => {
+  const commandBufferRef = { current: "sudo apt" };
+  const serialLineBufferRef = { current: "pending serial input" };
+  const autocompleteInputs: string[] = [];
+
+  clearTerminalInputStateForInterrupt({
+    commandBufferRef,
+    serialLineBufferRef,
+    onAutocompleteInput: (data) => autocompleteInputs.push(data),
+  });
+
+  assert.equal(commandBufferRef.current, "");
+  assert.equal(serialLineBufferRef.current, "");
+  assert.deepEqual(autocompleteInputs, ["\x03"]);
+});
+
+test("interrupt input state clearing tolerates terminals without serial line mode", () => {
+  const commandBufferRef = { current: "echo pending" };
+
+  assert.doesNotThrow(() => {
+    clearTerminalInputStateForInterrupt({ commandBufferRef });
+  });
+  assert.equal(commandBufferRef.current, "");
+});

components/terminal/runtime/terminalInterruptInputState.ts

@@ -0,0 +1,21 @@
+type StringRef = {
+  current: string;
+};
+
+type InterruptInputStateOptions = {
+  commandBufferRef: StringRef;
+  serialLineBufferRef?: StringRef;
+  onAutocompleteInput?: (data: string) => void;
+};
+
+export function clearTerminalInputStateForInterrupt({
+  commandBufferRef,
+  serialLineBufferRef,
+  onAutocompleteInput,
+}: InterruptInputStateOptions): void {
+  commandBufferRef.current = "";
+  if (serialLineBufferRef) {
+    serialLineBufferRef.current = "";
+  }
+  onAutocompleteInput?.("\x03");
+}