fix(server): report stalled SSH key authorization during fetch

[Gigioxx]

Problem

Starting a worktree from origin can wait on a GUI SSH agent's key approval (e.g. 1Password) for the full 30 seconds, then report only "Git command timed out." The user gets no hint that the SSH key is waiting for approval.

Change

When Git uses its default OpenSSH transport, fetchRemote watches OpenSSH's signing diagnostics and stops after 10 seconds without signing progress, with guidance to approve or unlock the key on the computer running T3 Code or use HTTPS. Sending the signed packet clears the deadline before network or pack waits, so slow fetches are unaffected. Custom SSH commands (GIT_SSH_COMMAND, GIT_SSH, core.sshCommand, ssh.variant) and clients without LogVerbose keep their existing behavior. Both the scoped fetch and the fetch-all path use the same monitor; fetch-all keeps main's stderr-derived failure detail.

Scope and approval

Fixes #11930, triaged as an accepted bug by a maintainer: #11930 (comment)

Verification

Problem established before the fix: isolated browser and server with real OpenSSH and a local SSH-agent fixture that withholds approval reproduced the 30-second generic timeout.

Checks run on the current head (rebased on main):

• vp test run src/vcs/GitVcsDriverCore.test.ts (apps/server): 112 passed. Covers stalled signing (scoped and fetch-all), stalled network handshake, slow fetch after signing, a second signing request, an older SSH client, a custom SSH command, single attempt, and process release.
• Server typecheck was not completed locally on this head (machine resource limits); relying on CI.
• vp lint and vp fmt --check on the two changed files: no errors (one pre-existing warning elsewhere in the test file).

Earlier manual check (before rebase): with the same fixture, the fixed fetch failed at 10 seconds with the approval prompt still open; approving the key let the same draft create its worktree and receive the agent's reply. The manual check was not repeated after the rebase. Not checked: Windows OpenSSH and non-1Password agents.

Before: generic timeout after 30s	After: authorization guidance after 10s

Before video · After video

Created with GPT-6 in Codex. Rebased and PR body updated by Claude Opus 5.5 in Claude Code.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The server-side fetch path now probes and modifies the default SSH transport, monitors authentication diagnostics, and can terminate a fetch with new timing and error behavior. Because this directly affects SSH authentication on a production request path, the change warrants human review despite its focused scope and extensive tests.

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• apps/server/src/vcs/GitVcsDriverCore.test.ts
• apps/server/src/vcs/GitVcsDriverCore.ts

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📝 Walkthrough

Walkthrough

fetchRemote now checks for the default OpenSSH transport and monitors signing diagnostics during eligible fetches. If signing stalls, the fetch returns an SSH key authorization timeout error. Full and branch-scoped fetches use the shared helper.

Changes

SSH fetch authorization monitoring

Layer / File(s)	Summary
Monitor default OpenSSH fetches apps/server/src/vcs/GitVcsDriverCore.ts	The shared helper checks whether the default OpenSSH transport is eligible for monitoring. It tracks signing diagnostics and reports an authorization timeout when signing stalls. Full and branch-scoped fetches use this helper.
Validate authorization timeout handling apps/server/src/vcs/GitVcsDriverCore.test.ts	Parameterized tests cover signing stalls, packet-only output, slow fetches after signing, fetch-all, older SSH clients, repeated signing, and custom SSH commands. The tests also check fetch attempts and process release.

Priority: ➖ Normal

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

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant fetchRemote
  participant OpenSSHProbe
  participant SharedFetchHelper
  participant GitFetch
  fetchRemote->>OpenSSHProbe: Check default OpenSSH eligibility
  OpenSSHProbe-->>SharedFetchHelper: Return probe result
  SharedFetchHelper->>GitFetch: Start fetch with signing diagnostics
  GitFetch-->>SharedFetchHelper: Emit signing diagnostic
  SharedFetchHelper-->>fetchRemote: Return result or authorization timeout

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Suggested reviewers: t3dotgg

Merge Risk: ⚪ Minimal · up to b4e2f

The change distinguishes stalled SSH key authorization from slow fetches while preserving custom SSH behavior. No concrete merge-blocking defect was established; merge after normal checks pass.

Architecture Summary

Architecture risk: 🔵 Low · up to b4e2f

The change affects 1 system.

Changed systems: apps/server

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — apps/server (service) was modified; 2 changed files map to changed impact.

Before / after behavior

• observed — Modified behavior in apps/server/src/vcs/GitVcsDriverCore.test.ts: Adds SSH fetch timeout tests with simulated signing and packet debug output. After advancing the test clock by 11 seconds, signing-stall cases (including fetch-all and repeated signing) are expected to report SSH key authorization failure; packet-only, slow-fetch-after-signing, older-client, and custom-command cases are expected to succeed. Each case checks that only one fetch ran and its process was released; the custom SSH case also checks that GIT_SSH_COMMAND is unset.
• observed — Modified behavior in apps/server/src/vcs/GitVcsDriverCore.ts: Adds the Queue import used by the fetch signing-diagnostic monitor.
• observed — Modified behavior in apps/server/src/vcs/GitVcsDriverCore.ts: Adds a shared fetch helper that detects eligible default OpenSSH configurations, enables verbose signing diagnostics, and races fetch execution against a sliding queue of signing events. When a signing diagnostic remains pending for 10 seconds, it fails with an SSH key authorization timeout error; otherwise it returns the fetch result. Custom SSH configuration, failed or timed-out probes, and other ineligible cases bypass monitoring.
• observed — Modified behavior in apps/server/src/vcs/GitVcsDriverCore.ts: Branch-scoped fetches now call the shared fetch helper, so they use the same SSH monitoring and timeout behavior as full fetches.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The pull request meets the coding requirements in #11930. GitVcsDriver.fetchRemote monitors default OpenSSH signing diagnostics and fails after 10 seconds without signing progress. The error provide…
Out of Scope Changes check	✅ Passed	The changes stay within #11930. Production changes add SSH authorization stall detection to GitVcsDriver.fetchRemote. Test changes cover the new behavior and compatibility cases. No unrelated produc…
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…
Title check	✅ Passed	The title clearly and concisely describes the main change: reporting stalled SSH key authorization during fetches.
Description check	✅ Passed	The description includes all required sections. It explains the problem, the implementation, scope approval, focused verification, limitations, and agent attribution. It also provides reproduction con…

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Actionable comments posted: 1

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Inline comments:
In `@apps/server/src/vcs/GitVcsDriverCore.test.ts`:
- Around line 2159-2234: Add a scenario in the authorization-timeout test around
fetchRemote that omits refName to exercise the fetch-all branch, while retaining
the existing assertions for timeout/error handling, successful completion,
attempt count, and process release. Use the existing driver, spawner, and
scenario setup rather than duplicating unrelated test infrastructure.

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• apps/server/src/vcs/GitVcsDriverCore.test.ts
• apps/server/src/vcs/GitVcsDriverCore.ts

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[maria-rcks]

Note

Written by claude-opus-5-5 on behalf of Maria

Hi! We are cleaning up open PRs, and this one appears to have been created with an older model (gpt-6). If this change is really important, we recommend rebuilding the PR with a newer model if possible.