fix(server): keep failed thread preparation safe to retry

[Adamulek123]

Failed worktree provisioning can leave an orphan checkout when cleanup also fails, so Retry can collide with its directory or branch. Main publishes a checkout binding only after provisioning succeeds. This PR makes a claimed survivor discoverable as incomplete and prevents Retry from treating it as a completed checkout.

Record the completed checkout path on the run and publish it with the workspace binding in one guarded server command. Retry reuses completed checkouts after setup failure. For an incomplete survivor, it preserves files and explains recovery: back up changes, explicitly remove the worktree and its branch with Git, then Retry. Release verifies the completed path before starting agent work. Setup-write failure closes its orphan terminal, and a prepared idle thread retains its checkout if shutdown interrupts later setup.

Cleanup also needs to distinguish an explicit workspace clear from the initial unbound state. Previously, a clear to null/null while removal was suspended could be overwritten by survivor repair. Each explicit branch/path write now records its command ID in the existing thread payload, even when the values are unchanged. Publication, delayed rename and cleanup check ownership under the existing per-thread dispatch lock. Cleanup recognizes only the original claim and this preparation's own committed write IDs. Unrelated title changes preserve ownership. A rejected survivor repair also leaves the progress tracker unchanged.

The identifier remains optional for legacy data and needs no database migration. Legacy runs without the checkout-completion fact retain released behavior. Completion proof remains a server-internal command, and authenticated clients keep their existing workspace selection capability. The shared server paths cover web, desktop, mobile and MCP callers. Cancellation, completed-checkout reuse, Stop and temporary-branch namespace fallback behavior are preserved.

Verified fix 95ee502103e72217e7c99dc21cbb28ce16f0969a, following normal main integration d7dafd316baa0c771ea867e1f438ab30c8d8552d with main 48b71f0eb323d08c8fcadfe54adf34becb2984da:

• 216 tests passed across the complete ThreadLaunchService, ProjectionStore, runtimeLayer and contracts orchestrationV2 suites.
• Twelve added regressions and controls cover same-valued clears, changes away and back, cleanup changes between read and final dispatch, progress state, successful publication, delayed rename, unrelated titles and legacy payloads.
• The original real-service/SQLite race failed before the fix with expected null and actual /claimed. It now passes. Interleavings use Deferred milestones and persisted events, without sleeps or polling.
• An independent Sol 6.1 reviewer passed 16 focused cases. The parent separately passed seven original-race and atomic-cleanup cases and reviewed the final commit.
• Targeted type-aware lint, formatting, diff whitespace, server and contracts typechecks passed. The existing unused-layer warning and nonblocking Effect suggestions remain.

Replaces the preparation part of #15310. Maintainer issue triage and scope approval remain outstanding. No live-client/provider or process-crash experiment was run.

Implemented and reviewed with GPT-6.1 Sol through Codex on Windows.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — This PR substantially changes production workspace preparation, cleanup, retry, and release behavior, including Git/filesystem and terminal side effects plus new persisted orchestration state. Its extensive tests are valuable, but the cross-component concurrency and contract-boundary changes require human review.

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[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between b865081 and b0d9b5a.

📒 Files selected for processing (4)

• apps/server/src/orchestration-v2/Orchestrator.ts
• apps/server/src/orchestration-v2/testkit/OrchestratorScenario.ts
• packages/contracts/src/orchestrationV2.ts
• packages/contracts/src/rpc.test.ts

💤 Files with no reviewable changes (1)

• apps/server/src/orchestration-v2/testkit/OrchestratorScenario.ts

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📝 Walkthrough

Walkthrough

Worktree preparation now records completed checkout paths and validates workspace bindings during setup and release. Cleanup and retry handling account for cancellation, failed provisioning, changed bindings, and existing checkouts. Setup-command write failures also trigger terminal cleanup.

Changes

Worktree preparation and recovery

Layer / File(s)	Summary
Workspace binding and completion packages/contracts/src/orchestrationV2.ts, apps/server/src/orchestration-v2/Orchestrator.ts, apps/server/src/orchestration-v2/runtimeLayer.test.ts, apps/server/src/orchestration-v2/testkit/OrchestratorScenario.ts, packages/contracts/src/rpc.test.ts	Run and command contracts carry completed workspace details and expected branch values. Orchestration checks expected workspace bindings, records completed worktree paths, and validates them before releasing prepared runs. Progress commands are server-only.
Worktree preparation and cleanup apps/server/src/orchestration-v2/ThreadLaunchService.ts, apps/server/src/orchestration-v2/ThreadLaunchService.test.ts, apps/server/src/project/ProjectSetupScriptRunner.ts, apps/server/src/project/ProjectSetupScriptRunner.test.ts	Launch preparation tracks created and renamed worktrees, setup terminals, and completion. Failure and cancellation cleanup handles worktree removal while preserving newer workspace bindings. Setup-command write failures now close the setup terminal.
Retry and checkout recovery apps/server/src/orchestration-v2/ThreadLaunchService.ts, apps/server/src/orchestration-v2/ThreadLaunchService.test.ts, docs/user/thread-sidebar.md	Retries reuse eligible completed worktrees and reject checkouts whose completion state is unknown. Tests and documentation cover failed provisioning, setup retries, and checkout cleanup.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~60 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant ThreadLaunchService
  participant Orchestrator
  participant ProjectSetupScriptRunner
  participant Terminal
  ThreadLaunchService->>Orchestrator: Record completed workspace
  ThreadLaunchService->>ProjectSetupScriptRunner: Run setup script
  ProjectSetupScriptRunner->>Terminal: Write setup command
  ThreadLaunchService->>Orchestrator: Release prepared run

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Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to b0d9b

Normal worktree preparation has no demonstrated path to the previously reported failure. No actionable merge-blocking risk remains after normal checks.

Security Architecture Review

Security architecture risk: 🔵 Low · up to b0d9b

The change strengthens protection against starting agent work in an incompletely prepared checkout. A narrow cleanup race can still restore a workspace binding after it was explicitly cleared. Its immediate impact is limited because completion checks continue to block unsafe reuse. Compatibility during downgrade remains unproven.

Retained concerns

• Low · reliability · inferred: The new failed-removal repair can undo a newer explicit workspace clear. With an automatically generated branch, the original requested branch is null; cleanup therefore accepts a current null path/null branch as launch-owned and republishes the surviving checkout. Expected-value checks cannot distinguish that newer clear from the original unbound state. This weakens recovery ownership and can leave Retry requiring manual removal, although the null completion proof still prevents incomplete-checkout reuse. The base cleanup did not perform this survivor rebind.

Security review details

Security Blast Radius

• inferred — The demonstrated effects concern a thread's workspace binding, its project worktree and branch, setup terminal, and queued agent release. Exploiting the identified ownership race requires workspace-mutation authority plus overlapping cleanup failure. No cross-tenant or additional credential authority is established by this evidence.

Security Findings and Attack Paths

• observed — The examined forged-completion path is rejected at WebSocket payload decoding. The regression exercises the registered RPC payload schema, rather than only a server-side type declaration. This does not establish complete security coverage of every orchestration command.

Trust Boundaries and Controls

• observed — Client Retry routes to launch-owned scheduling, while provisioning completion is asserted internally after Git provisioning returns. Expected path/branch checks protect publication; exact completion-path checks protect new-row reuse and release. Existing client workspace-mutation authority is counterevidence against treating the completion marker as a general filesystem access boundary.

Resilience and Maintainability Implications

• observed — Retry requires a failed preparation, rejects archived or deleted threads and competing blocking runs, and refuses an existing checkout whose completion cannot be established. These controls contain the immediate impact of the cleanup ownership race, but legacy rows deliberately retain weaker historical classification.

Hardening Proposals

• proposed — Use a preparation ownership token or binding generation to distinguish an explicit clear from the original null/null binding. Separately, define downgrade handling for incomplete survivors before returning to code that ignores completion proof.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 8 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check		The description covers the problem, implementation, verification, compatibility, and limitations. It does not satisfy the required Scope and approval content because it states that maintainer issue tr…	Add a link to the triaged issue or approval discussion with explicit maintainer approval of the direction and scope. If the change qualifies for an approval exemption, explain why.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title is concise, specific, and accurately describes the main change: making failed thread preparation safe to retry.

Full details: Description check

Explanation

The description covers the problem, implementation, verification, compatibility, and limitations. It does not satisfy the required Scope and approval content because it states that maintainer issue triage and scope approval remain outstanding.

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[coderabbitai]

Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @packages/contracts/src/orchestrationV2.ts:
- Around line 2765-2772: Update the completedWorkspace schema to use
TrimmedNonEmptyString for worktreePath and branch, and
Schema.NullOr(TrimmedNonEmptyString) for expectedWorktreePath and
expectedBranch. Apply the same trimmed schema to the run’s completedWorktreePath
so both event payloads normalize paths consistently.

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ℹ️ Review info

⚙️ Run configuration

• Configuration used: Repository: pingdotgg/t3code/.coderabbit.yaml
• Review profile: CHILL
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• Run ID: 0e12e18c-b43f-4005-bd97-9c950f1b6a8c

📥 Commits

Reviewing files that changed from the base of the PR and between efecd3c and b865081.

📒 Files selected for processing (8)

• apps/server/src/orchestration-v2/Orchestrator.ts
• apps/server/src/orchestration-v2/ThreadLaunchService.test.ts
• apps/server/src/orchestration-v2/ThreadLaunchService.ts
• apps/server/src/orchestration-v2/runtimeLayer.test.ts
• apps/server/src/project/ProjectSetupScriptRunner.test.ts
• apps/server/src/project/ProjectSetupScriptRunner.ts
• docs/user/thread-sidebar.md
• packages/contracts/src/orchestrationV2.ts

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