fix(init): release stdin handle to unblock event loop on wizard exit

[BYK]

Summary

At the end of a sentry init flow, the process hangs until the user presses a key. Follow-up to #802, #824, #825 — addresses the third and final contributor to the post-wizard hang.

Root cause

Our no-op patch of process.stdin.pause silently swallowed clack's rl.close() → input.pause() call. Stdin stayed in flowing/ref'd mode from readline.createInterface()'s internal input.resume(), keeping the libuv event loop alive until any keypress delivered a data event.

Why the patch was needed

stdin-reopen.ts replaces process.stdin.pause/resume with no-ops at install time to dodge Bun's fd-0 EINVAL on pause/resume transitions (see the comment at the install site). That fix is correct and must stay.

Why the bug was invisible

rl.close() is the only place clack ever pauses stdin — it relies entirely on Node's standard readline cleanup discipline. Our no-op patch swallowed every call without any visible error, so there was no log line, no warning, no failed assertion.

Why PRs #802/#824/#825 didn't catch it

• fix(init): release /dev/tty handle on all exit paths #802 fixed the /dev/tty ReadStream contribution (explicit .destroy()).
• fix(init): harden /dev/tty teardown and adopt Symbol.dispose #824 adopted using/Symbol.dispose for guaranteed teardown + termios restore.
• fix(init): cancel in-flight Mastra requests on teardown #825 aborted the MastraClient signal to release keep-alive sockets.

Post-teardown state after all three fixes:

• /dev/tty ReadStream: destroyed ✓
• MastraClient AbortController: aborted ✓
• process.stdin: still ref'd and flowing ✗ ← the remaining anchor

PR #782's original process.exit(0) workaround masked this by killing the process unconditionally. Each subsequent PR peeled off one contributor; stdin was the last one standing.

Fix

One call to the just-restored original.pause at the end of closeFreshTtyForwarding():

// Release the libuv handle on fd 0. Clack's prompt lifecycle relies on
// `rl.close() → rl.pause() → this.input.pause()` to pause stdin, but we
// replaced `process.stdin.pause` with a no-op at install time... Now that
// the original `.pause()` is restored, invoke it directly so stock
// Node/Bun cleanup can finish. Idempotent: safe when stdin was already
// paused.
try {
  original.pause.call(process.stdin);
} catch {
  // Defensive: swallow errors from runtimes that throw if stdin is
  // already destroyed.
}

Rationale for .pause() over alternatives:

• Exactly what Node's rl.close() would have called — matches clack's implicit contract.
• Idempotent on already-paused streams.
• Doesn't destroy the stream (unlike .destroy()); any future code that wanted to read stdin (none does in init; it's a terminal command) could still resume.

Regression tests

Two new tests in test/lib/init/stdin-reopen.test.ts:

Unit: teardown invokes restored pause exactly once

Replaces the beforeEach stub with a counting spy BEFORE install (so install captures the spy as original.pause). Verifies:

• During install, process.stdin.pause is the patched no-op (not the spy).
• Calls made mid-wizard hit the no-op (spy count stays 0).
• After teardown, process.stdin.pause is restored to the spy AND the spy was invoked exactly once.

Integration: stdin is not flowing after teardown

Puts process.stdin into flowing mode via real Readable.prototype.resume (simulating what clack does via readline.createInterface). Runs install + teardown. Asserts process.stdin.readableFlowing !== true after disposal — without the fix, this assertion would fail because the no-op pause never actually pauses.

Test plan

• bun test test/lib/init/stdin-reopen.test.ts — 15 pass (13 existing + 2 new)
• bun test test/lib/init/ test/commands/init.test.ts — 193 pass
• bun test --timeout 15000 test/lib test/commands test/types — 5777 pass, 0 fail
• bun run typecheck — clean
• bun run lint — clean (only pre-existing markdown.ts warning)
• Manual: curl -fsSL https://cli.sentry.dev/install | SENTRY_INIT=1 bash — shell prompt should return immediately after "Setup complete" without a keypress.

Risk

Very low. Single call to a restored function (known state) guarded by try/catch. No API changes, no new dependencies, no test fixture churn. Two new tests exercise the exact regression.

Out of scope

• Revisiting whether the no-op pause/resume patch is still necessary with current Bun (Bun's fd-0 EINVAL may be fixed — worth investigating later as a simplification, but not as part of this hot-fix).
• E2E spawn test asserting process-exits-without-keypress (requires pty fixture infrastructure we don't currently have).

[github-actions]

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Codecov Results 📊

✅ 138 passed | Total: 138 | Pass Rate: 100% | Execution Time: 0ms

📊 Comparison with Base Branch

Metric	Change
Total Tests	—
Passed Tests	—
Failed Tests	—
Skipped Tests	—

✨ No test changes detected

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 1941 uncovered lines.
❌ Project coverage is 95.3%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    95.31%    95.30%    -0.01%
==========================================
  Files          284       284         —
  Lines        41337     41340        +3
  Branches         0         0         —
==========================================
+ Hits         39401     39399        -2
- Misses        1936      1941        +5
- Partials         0         0         —

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