fix(gdb): keep inferior-tty verification for read-only queries (#5539)

* fix(gdb): keep TTY verification across read-only inferior-tty inspection

The console command path cleared `inferiorTtyVerified` before dispatching
any command whose text merely mentioned `inferior-tty`, so the read-only
`show inferior-tty` query permanently revoked a persistent session's
verified output sink; no in-session path ever restored the flag, and a
later close of a live session failed detach verification with
capability_unavailable.

Exempt the exact read-only query forms (`show inferior-tty` and the MI
`-inferior-tty-show`) from the output-mutation predicate; every other
command mentioning the TTY setting keeps revoking, so mutating commands
still fail closed and detach keeps re-reading the live TTY before
detaching. Cover the query forms, composite commands, and the
inspect-then-close detach path with regression tests.

Fixes #5099

* test(gdb): classify show inferior-tty in the one-shot table and rename the TTY classification table

- Add a 'show inferior-tty' row to the 'classifies one-shot GDB
  commands' table: the read-only query no longer invalidates the detach
  proof, a user-visible one-shot behavior change.
- Rename the 'classifies read-only inferior TTY queries as non-mutating'
  table to 'classifies inferior TTY commands' since two of its rows are
  mutation cases.
- Assert via the existing recorded-commands array that the inspected
  'show inferior-tty' text is actually dispatched, and add an
  execute-path assertion that the MI '-inferior-tty-show' form leaves
  the verified-sink flag intact (defensive exemption: REA's own MI calls
  do not route through this gate).

---------

Co-authored-by: akushonkamen <akushonkamen@users.noreply.github.com>

src/gdb/GdbSessionManager.ts

@@ -2429,9 +2429,15 @@ export const gdbOneShotCommandMayInvalidateDetachProof = (
 
 /** @internal Classify commands that can invalidate the configured output sink. */
 export const commandMayChangeInferiorOutput = (command: string): boolean => {
-  // These complete built-in inspections cannot change output routing. Keep
-  // compound commands and abbreviations under the conservative rules below.
-  if (/^[ \t]*(?:show|help)[ \t]+inferior-tty[ \t]*$/iu.test(command))
+  // These exact read-only TTY inspections ("show inferior-tty", "help
+  // inferior-tty", MI "-inferior-tty-show") cannot reconfigure the output
+  // sink, so they must not revoke the startup verification. Keep compound
+  // commands and abbreviations under the conservative rules below
+  // (fail-closed).
+  if (
+    /^[ \t]*(?:show|help)[ \t]+inferior-tty[ \t]*$/iu.test(command) ||
+    /^[ \t]*-inferior-tty-show[ \t]*$/iu.test(command)
+  )
     return false;
   const setting = /^\s*(?:set|with)\s+(\S+)/iu.exec(command)?.[1];
   const maySetInferiorTty =

tests/boundary/providers/GdbSessionManagerCoverage.test.ts

@@ -177,10 +177,22 @@ it.each([
   ["so commands.gdb", true],
   ["de", true],
   ["p 1; python print(2)", true],
+  ["show inferior-tty", false],
 ] as const)("classifies one-shot GDB commands: %s", (command, expected) => {
   expect(gdbOneShotCommandMayInvalidateDetachProof(command)).toBe(expected);
 });
 
+it.each([
+  ["show inferior-tty", false],
+  ["  show inferior-tty  ", false],
+  ["-inferior-tty-show", false],
+  ["set inferior-tty /tmp/output", true],
+  ["show inferior-t; set inferior-tty /tmp/output", true],
+  ["show inferior-tty; define redirect = run > /tmp/output", true],
+] as const)("classifies inferior TTY commands: %s", (command, expected) => {
+  expect(commandMayChangeInferiorOutput(command)).toBe(expected);
+});
+
 it.each([
   [new Error("provider failure"), "provider failure"],
   ["non-error provider failure", "non-error provider failure"],
@@ -2784,6 +2796,67 @@ it.each([
   }
 });
 
+it("keeps the verified sink across the read-only show inferior-tty inspection", async () => {
+  const tty = "/dev/pts/42";
+  const commands: string[] = [];
+  let detached = false;
+  const fake = createFakeSpawner((_child, token, command) => {
+    commands.push(command);
+    if (command.includes("inferior-tty-show"))
+      fake.children[0]?.stdout.write(
+        `${token}^done,inferior_tty_terminal=${JSON.stringify(tty)}\n`,
+      );
+    else if (command.includes("list-thread-groups"))
+      fake.children[0]?.stdout.write(
+        detached
+          ? `${token}^done,groups=[]\n`
+          : `${token}^done,groups=[{id="i1",pid="123"}]\n`,
+      );
+    else {
+      if (command.includes("target-detach")) detached = true;
+      fake.children[0]?.stdout.write(`${token}^done\n`);
+    }
+  });
+  const manager = managerWithFakeSpawner(fake.spawnProcess);
+  const started = await expectGdbSessionStarted(manager, undefined, {
+    inferiorTty: tty,
+  });
+
+  const inspected = await manager.execute(
+    started.value.session_id,
+    "show inferior-tty",
+  );
+
+  expect(inspected.ok).toBe(true);
+  expect(manager.status(started.value.session_id)).toMatchObject({
+    inferior_tty: tty,
+    inferior_tty_verified: true,
+  });
+  expect(commands).toContain('-interpreter-exec console "show inferior-tty"');
+
+  // The MI form is a defensive exemption: REA's own MI calls do not route
+  // through this user-command gate, and the console interpreter may reject
+  // the text outright. The gate must still leave the verified flag alone.
+  const inspectedMi = await manager.execute(
+    started.value.session_id,
+    "-inferior-tty-show",
+  );
+
+  expect(inspectedMi.ok).toBe(true);
+  expect(manager.status(started.value.session_id)?.inferior_tty_verified).toBe(
+    true,
+  );
+
+  const closed = await manager.close(started.value.session_id);
+
+  expect(closed).toMatchObject({
+    ok: true,
+    value: { target_state: "unknown" },
+  });
+  expect(commands).toContain("-target-detach");
+  expect(fake.children[0]?.killSignals).toEqual(["SIGTERM"]);
+});
+
 it("revokes the verified sink after an abbreviated with inferior-tty run command", async () => {
   const tty = "/dev/pts/42";
   const commands: string[] = [];