Fix hung Google token refresh permanently freezing calendar sync

[GeoffreyPlitt]

Status

READY

Description

Fixes a reliability bug in the Google Calendar provider where a single hung OAuth token refresh permanently freezes all calendar refreshes with no error, no retry, and no user-visible signal.

This caused a real user-facing failure (observed on v4.11.6; the same pattern exists on master): token refreshes stopped silently after a sleep/wake cycle, the menu kept showing the previous day's events all greyed out (past-event styling), the status bar lost its countdown, and no notifications fired until the app was manually restarted.

Root cause (GCEventStore.validAccessToken): token refreshes are serialized through a stored refreshTask, and the task body wraps AppAuth's OIDAuthState.performAction callback in a continuation. If performAction never invokes its callback (observed in the wild — e.g. its internal token-endpoint request gets parked across sleep/wake), the continuation never resumes, defer { refreshTask = nil } never runs, and every subsequent fetch awaits the dead task forever. There was no timeout anywhere in this path. Additionally, the guard let self else { return } inside the callback could leak the continuation outright, and the same serialize-through-a-stored-task pattern in ensureSignedIn/signInTask had the same wedge risk.

Fix:

• New TimeoutGuardedCompletion helper (in GoogleCalendarPolicy.swift, part of the MeetingBarLogic package) that races a completion-callback-based operation against a hard timeout and guarantees the continuation resumes exactly once, even when the timeout and a late callback race.
• validAccessToken wraps performAction with a 30s timeout; on timeout it throws AuthError.refreshFailed, refreshTask is always cleared, and the existing ProviderHealth machinery surfaces the stale-data warning as it already does for thrown errors.
• ensureSignedIn gets the same protection with a 5-minute timeout (interactive sign-in can legitimately take a while), so a never-completing sign-in can no longer block all future refreshes.
• The guard let self continuation leak is gone — the AppAuth callback no longer touches self.

No public API changes; EventKit provider untouched.

Checklist

• Localized (no user-facing strings added)
• Added to changelog — no unreleased section exists yet; happy to add entries once the target version is known:
  • Changelog View
  • CHANGELOG.md

Steps to Test or Reproduce

1. make test — new unit tests in MeetingBarLogicTests/TimeoutGuardedCompletionTests.swift cover: a callback that never fires throws within the timeout instead of hanging; a late callback after timeout is safely ignored (no double-resume crash); a subsequent call is not blocked by an earlier hung operation; fast success/failure paths are unaffected.
2. Full CI (SwiftPM logic tests + app-hosted tests + lint) is green on the fork: 213 + 429 tests, 0 failures.
3. The hung-callback condition itself only reproduces on rare network/sleep-wake edge cases, so end-to-end verification was regression-focused: sign-in and calendar refresh flow through the new timeout wrapper unchanged.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Google Calendar sign-in now completes with a clear cancellation or timeout result instead of remaining indefinitely.
  • Token refresh operations are time-limited and report a refresh failure when they exceed the allowed duration.
  • Authentication state continues to be cleared appropriately when authorization is no longer valid.
• Tests
  • Added coverage for sign-in and token-refresh timeout behavior, delayed callbacks, failures, and subsequent operations.

[coderabbitai]

Walkthrough

Google authentication now bounds interactive sign-in and token refresh operations with timeout guards. A single-resume helper handles late callbacks safely, and tests cover timeout, success, failure, late completion, and independent subsequent calls.

Changes

Google authentication timeout handling

Layer / File(s)	Summary
Guarded completion infrastructure MeetingBar/Calendar/Providers/Google/GoogleCalendarPolicy.swift	Adds timeout errors, callback-versus-timeout racing, and locking to prevent continuation double-resumption.
Google sign-in and refresh integration MeetingBar/Calendar/Providers/Google/GoogleCalendarEventStore.swift	Applies separate sign-in and token-refresh timeouts while preserving authentication error handling.
Timeout behavior validation MeetingBarLogicTests/TimeoutGuardedCompletionTests.swift	Tests timeout, fast success, error propagation, late callbacks, and independent later calls.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant GCEventStore
  participant TimeoutGuardedCompletion
  participant AppAuth
  GCEventStore->>TimeoutGuardedCompletion: guard sign-in or token refresh
  TimeoutGuardedCompletion->>AppAuth: start completion-based operation
  AppAuth-->>TimeoutGuardedCompletion: return callback result or timeout
  TimeoutGuardedCompletion-->>GCEventStore: return authentication result

Loading

Possibly related PRs

• leits/MeetingBar#835: Both changes modify Google GCEventStore sign-in handling and signInTask behavior.

Poem

A bunny guards the sign-in gate,
No callback may make us wait.
Refresh hops safely through the night,
Late replies vanish out of sight.
Tests bloom bright in carrot rows—
Auth now bounds its endless woes!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main fix: preventing a hung Google token refresh from blocking calendar sync.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@MeetingBar/Calendar/Providers/Google/GoogleCalendarEventStore.swift`:
- Around line 298-313: The sign-in timeout in ensureSignedIn should be converted
to AuthError.refreshFailed, matching validAccessToken. Update the surrounding
Task/TimeoutGuardedCompletion error handling to catch OperationTimedOut and
rethrow AuthError.refreshFailed, while preserving other errors unchanged.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: d509964a-1e24-43e9-b24c-cb18122103c5

📥 Commits

Reviewing files that changed from the base of the PR and between 88519a4 and 04f1a19.

📒 Files selected for processing (3)

• MeetingBar/Calendar/Providers/Google/GoogleCalendarEventStore.swift
• MeetingBar/Calendar/Providers/Google/GoogleCalendarPolicy.swift
• MeetingBarLogicTests/TimeoutGuardedCompletionTests.swift