fix(ai): preserve shell hooks when stopping command input

electron/bridges/ai/ptyExec.test.cjs

@@ -967,63 +967,24 @@ test("posix wrapper keeps cd contained in the subshell (documented trade-off)",
   }
 });
 
-// Issue #3485: interactive bash 4.4+ expands PS0 after reading a command and
-// before executing it, so a user-defined PS0 hook (commonly a timestamp from
-// ~/.bashrc; root usually has none) prints extra output inside the hidden
-// wrapper's echo window. The wrapper must silence it for its own reads and
-// restore the original value afterwards.
-test("posix wrapper saves PS0 before wrapping and restores it after execution", () => {
-  const marker = "__NCMCP_TEST__";
-  const wrapped = buildWrappedCommand("echo PS0_HOOK_TEST", "posix", marker);
-  assert.match(wrapped, /\[ -n "\$\{PS0-\}" \]&&\{ __NCMCP_PS0=\$\{PS0-\}; PS0=; \}; printf/);
-  assert.match(
-    wrapped,
-    /\[ -n "\$\{__NCMCP_PS0-\}" \]&&\{ PS0=\$\{__NCMCP_PS0-\}; unset __NCMCP_PS0; \}; \(exit \$__NCMCP_rc\); \}/,
-  );
+// A cancelled paced delivery may execute only the first physical line.
+// Neither partial delivery nor a complete command may change user shell hooks.
+for (const [partial, hasPS0] of [[true, true], [false, true], [true, false], [false, false]]) {
+  test(`posix ${partial ? "partial" : "complete"} wrapper preserves ${hasPS0 ? "set" : "unset"} PS0 and existing shell state`, () => {
+    const marker = "__NCMCP_TEST__";
+    const wrapped = buildWrappedCommand("echo HOOK_STATE_TEST", "posix", marker);
+    const script = partial ? wrapped.slice(0, wrapped.indexOf("\n") + 1) : wrapped;
+    const result = spawnSync("bash", ["--norc", "-c",
+      (hasPS0 ? 'PS0="[hook] "; ' : 'unset PS0; ') + '__NCMCP_PS0=user_value\n' + script
+        + 'printf "HOOK_STATE=<%s> SCRATCH=<%s>\\n" "$PS0" "$__NCMCP_PS0"',
+    ], { encoding: "utf8" });
 
-  const result = spawnSync(
-    "bash",
-    ["--norc", "-c", 'PS0="[hook] "\n' + wrapped + 'printf "RESTORED_PS0=%s\\n" "$PS0"'],
-    { encoding: "utf8" },
-  );
-
-  assert.equal(result.error, undefined);
-  assert.equal(result.status, 0);
-  assert.match(result.stdout, new RegExp(`${marker}_E:0`));
-  assert.match(result.stdout, /PS0_HOOK_TEST/);
-  // The user's PS0 value is back once the wrapper group finishes, so their
-  // own subsequent commands still run the hook.
-  assert.match(result.stdout, /RESTORED_PS0=\[hook\] /);
-});
-
-test("posix wrapper leaves PS0 alone when the user has none set", () => {
-  const marker = "__NCMCP_TEST__";
-  const wrapped = buildWrappedCommand("echo NO_PS0_TEST", "posix", marker);
-  const result = spawnSync(
-    "bash",
-    ["--norc", "-c", `unset PS0\n${wrapped}printf "PS0_SET=[%s]\\n" "\${PS0-}"`],
-    { encoding: "utf8" },
-  );
-
-  assert.equal(result.error, undefined);
-  assert.equal(result.status, 0);
-  assert.match(result.stdout, new RegExp(`${marker}_E:0`));
-  // Nothing was saved and nothing is restored: PS0 stays unset afterwards.
-  assert.match(result.stdout, /NO_PS0_TEST/);
-  const ps0Line = result.stdout.split("\n").find((line) => line.startsWith("PS0_SET="));
-  assert.equal(ps0Line, "PS0_SET=[]");
-});
-
-test("posix wrapper silencing still works under sh (dash) where PS0 does not exist", () => {
-  const marker = "__NCMCP_TEST__";
-  const wrapped = buildWrappedCommand("echo DASH_TEST", "posix", marker);
-  const result = spawnSync("sh", ["-c", `${wrapped}printf 'SH_ALIVE\\n'`], { encoding: "utf8" });
-
-  assert.equal(result.error, undefined);
-  assert.equal(result.status, 0);
-  assert.match(result.stdout, new RegExp(`${marker}_E:0`));
-  assert.match(result.stdout, /SH_ALIVE/);
-});
+    assert.equal(result.error, undefined);
+    assert.equal(result.status, 0, result.stderr);
+    assert.ok(result.stdout.includes(`HOOK_STATE=<${hasPS0 ? "[hook] " : ""}> SCRATCH=<user_value>`), result.stdout);
+    if (!partial) assert.match(result.stdout, new RegExp(`${marker}_E:0`));
+  });
+}
 
 // Issue #3265: with plain HISTCONTROL the wrapper line is recorded in bash
 // history; arrow-up recall then redraws the marker text, the preload __NCMCP_

electron/bridges/ai/ptyExecHelpers.cjs

@@ -274,27 +274,16 @@ function buildPosixWrapperBody(command, marker, startFormat, { omitBashHistoryCl
     cmdAssign = `${marker}_cmd=$(${writes.join(`; \\\n: '${marker}'; `)})`;
   }
   const historyCleanup = omitBashHistoryCleanup ? [] : [buildBashHistoryCleanup(marker)];
-  // Issue #3485: interactive bash 4.4+ expands PS0 after reading a command
-  // and before executing it. A user-set PS0 hook (commonly a pre-exec
-  // timestamp/hook defined in ~/.bashrc — root usually has none) prints extra
-  // output inside the hidden wrapper's echo window, garbling the agent's
-  // command echo while manual typing renders natively. Save PS0 only while it
-  // is currently set (so an interrupted run cannot overwrite the saved value
-  // with empty), silence it for every wrapper read, and restore it after the
-  // wrapper group finishes. zsh/dash/fish have no PS0, so both guards are
-  // no-ops there.
-  const ps0Save = '[ -n "${PS0-}" ]&&{ __NCMCP_PS0=${PS0-}; PS0=; }';
-  const ps0Restore = '[ -n "${__NCMCP_PS0-}" ]&&{ PS0=${__NCMCP_PS0-}; unset __NCMCP_PS0; }';
   // OpenWrt builds BusyBox with a 512-byte interactive line editor. Keep
   // every physical line below that limit, even for short user commands.
   // Emit a short standalone input marker before the shell reads any PS2
   // continuation. A leading newline separates it from concurrent PTY echo.
-  return `${marker}=0; ${ps0Save}; printf '\\n%s\\n' '${marker}_I'\n` + [
+  return `${marker}=0; printf '\\n%s\\n' '${marker}_I'\n` + [
     ` : '${marker}'; ${cmdAssign}`,
     `{ printf '${startFormat}' '${marker}_S'; trap ':' INT; ( ${noPager}eval "$${marker}_cmd" ); __NCMCP_rc=$?; trap - INT`,
     `printf '%s\\n' '${marker}_E:'"$__NCMCP_rc"`,
     ...historyCleanup,
-    `${ps0Restore}; (exit $__NCMCP_rc); }`,
+    `(exit $__NCMCP_rc); }`,
   ].join(`; \\\n: '${marker}'; `);
 }