fix(terminals): le reattach xterm ne réinjecte plus les réponses synthétiques du replay scrollback — #292 (term.onData n'est actif qu'après le callback final du term.write(scrollback): les réponses aux requêtes historiques ESC[1;1R/modes ne peuplent plus pending ni ne sont réécrites dans le PTY par adopt, ce qui bouclait CPU 100% sur les agents Git TUI Native d'UnitySoundTool/UnityPlugin; activation de l'input aussi sur les chemins fallback reattach-échoué et terminal neuf; test de régression: zéro write PTY pendant le replay synthétique puis exactement un write pour Hello\r; QA verte: 3 fichiers/27 tests TerminalView, npm run build frontend, AppImage 0.3.0 rebuild sha256 4165521e...; réserve: repro live UI trois projets non validée depuis sandbox)

frontend/src/features/terminals/TerminalView.scrollback.test.tsx

@@ -1,11 +1,18 @@
-import { describe, it, expect, vi } from "vitest";
+import { beforeEach, describe, it, expect, vi } from "vitest";
-import { render } from "@testing-library/react";
+import { render, waitFor } from "@testing-library/react";
 
-import type { Gateways } from "@/ports";
+import type { Gateways, ReattachResult, TerminalHandle } from "@/ports";
 import { MockTerminalGateway } from "@/adapters/mock";
 import { DIProvider } from "@/app/di";
 
 const terminalOptions: unknown[] = [];
+const xtermState: {
+  keyHandler: ((data: string) => void) | null;
+  answerOnWrite: string | null;
+} = {
+  keyHandler: null,
+  answerOnWrite: null,
+};
 
 vi.mock("@xterm/xterm", () => ({
   Terminal: class {
@@ -18,11 +25,19 @@ vi.mock("@xterm/xterm", () => ({
 
     loadAddon() {}
     open() {}
-    onData() {
+    onData(callback: (data: string) => void) {
+      xtermState.keyHandler = callback;
       return { dispose() {} };
     }
-    write() {}
+    write(_data: string | Uint8Array, callback?: () => void) {
-    input() {}
+      if (xtermState.answerOnWrite) {
+        xtermState.keyHandler?.(xtermState.answerOnWrite);
+      }
+      callback?.();
+    }
+    input(data: string) {
+      xtermState.keyHandler?.(data);
+    }
     focus() {}
     dispose() {}
   },
@@ -49,6 +64,12 @@ import {
   TERMINAL_SCROLLBACK_LINES,
 } from "./TerminalView";
 
+beforeEach(() => {
+  terminalOptions.length = 0;
+  xtermState.keyHandler = null;
+  xtermState.answerOnWrite = null;
+});
+
 describe("TerminalView scrollback", () => {
   it("configures xterm with a deep scrollback for chatty OpenCode agents", async () => {
     const gateways = { terminal: new MockTerminalGateway() } as unknown as Gateways;
@@ -64,4 +85,51 @@ describe("TerminalView scrollback", () => {
     });
     expect(TERMINAL_SCROLLBACK_LINES).toBeGreaterThan(1_000);
   });
+
+  it("does not relay synthetic xterm answers from reattach replay, then writes human input once", async () => {
+    const write = vi.fn().mockResolvedValue(undefined);
+    const handle: TerminalHandle = {
+      sessionId: "live-loop-regression",
+      write,
+      resize: vi.fn().mockResolvedValue(undefined),
+      detach: vi.fn(),
+      close: vi.fn().mockResolvedValue(undefined),
+    };
+    const reattach = vi.fn(async () => {
+      const result: ReattachResult = {
+        handle,
+        // Represents retained TUI output containing a terminal query. The xterm
+        // stub answers from write(), exactly where the real ESC[1;1R burst was
+        // produced on the affected Git agents.
+        scrollback: new TextEncoder().encode("\x1b[6n"),
+      };
+      return result;
+    });
+    const gateways = {
+      terminal: {
+        openTerminal: vi.fn(),
+        reattach,
+        closeTerminal: vi.fn(),
+      },
+    } as unknown as Gateways;
+    xtermState.answerOnWrite = "\x1b[1;1R";
+
+    render(
+      <DIProvider gateways={gateways}>
+        <TerminalView cwd="/cwd" sessionId="live-loop-regression" />
+      </DIProvider>,
+    );
+
+    await waitFor(() => expect(reattach).toHaveBeenCalledTimes(1));
+    await waitFor(() => expect(xtermState.keyHandler).not.toBeNull());
+
+    // The response synthesized while replaying retained output never reaches
+    // pending/adopt and therefore never loops back into the PTY.
+    expect(write).not.toHaveBeenCalled();
+
+    xtermState.keyHandler!("Hello\r");
+
+    await waitFor(() => expect(write).toHaveBeenCalledTimes(1));
+    expect(new TextDecoder().decode(write.mock.calls[0][0])).toBe("Hello\r");
+  });
 });

frontend/src/features/terminals/TerminalView.tsx

@@ -238,7 +238,10 @@ export function TerminalView({
     // not race the injected text. Keystrokes arriving before the PTY opened are
     // buffered. The output path below is unchanged in both modes.
     let pending = "";
-    const onKey = term.onData((data) => {
+    let onKey: { dispose: () => void } | null = null;
+    const activateInput = () => {
+      if (disposed || onKey) return;
+      onKey = term.onData((data) => {
         const portal = portalRef.current;
         if (agentModeRef.current && portal) {
           // Always report for counting (even while suspended — the portal decides
@@ -250,7 +253,7 @@ export function TerminalView({
         else pending += data;
       });
 
-    // Publish the input API now that the keystroke relay above is live, so an
+      // Publish the input API only once the keystroke relay is live, so an
       // injected key is handled exactly like a typed one. Guarded on `disposed`:
       // the caller may still hold this object after the cell unmounts, and driving
       // a disposed xterm throws.
@@ -262,6 +265,7 @@ export function TerminalView({
           if (!disposed) term.focus();
         },
       });
+    };
 
     const onData = (bytes: Uint8Array) => {
       if (!disposed) term.write(bytes);
@@ -321,13 +325,27 @@ export function TerminalView({
             h.detach();
             return;
           }
-          if (scrollback.length > 0) term.write(scrollback);
+          const finishReattach = () => {
+            if (disposed) {
+              h.detach();
+              return;
+            }
+            // A scrollback replay can make xterm answer historical terminal
+            // queries (cursor position, device attributes, modes…). Keep the
+            // input relay absent until xterm confirms the replay is complete,
+            // otherwise those synthetic answers enter `pending` and are sent
+            // back into the live PTY by `adopt`, creating a feedback loop.
+            activateInput();
             adopt(h);
+          };
+          if (scrollback.length > 0) term.write(scrollback, finishReattach);
+          else finishReattach();
         })
         .catch(() => {
           // The session is gone (explicitly closed / exited): fall back to a
           // fresh terminal so the cell still works.
           if (disposed) return;
+          activateInput();
           opener({ cwd, rows: term.rows, cols: term.cols }, onData)
             .then((h) => {
               onSessionIdRef.current?.(h.sessionId);
@@ -336,6 +354,9 @@ export function TerminalView({
             .catch(onOpenError);
         });
     } else {
+      // A fresh terminal has no historical output to replay. Enable input now
+      // so genuine keystrokes typed while the opener resolves remain buffered.
+      activateInput();
       opener({ cwd, rows: term.rows, cols: term.cols }, onData)
         .then((h) => {
           onSessionIdRef.current?.(h.sessionId);
@@ -468,7 +489,7 @@ export function TerminalView({
       window.removeEventListener("pageshow", scheduleSettledRefit);
       document.removeEventListener("visibilitychange", scheduleVisibleRefit);
       window.visualViewport?.removeEventListener("resize", scheduleSettledRefit);
-      onKey.dispose();
+      onKey?.dispose();
       portalRef.current?.unbindHandle();
       // DETACH, never close: tearing the view down (navigation / layout change)
       // must leave the backend PTY running so the AI isn't cut off. Killing the