[Fix] Task history can disappear when users restart after completion by zoomote[bot] · Pull Request #1452 · Zoo-Code-Org/Zoo-Code

zoomote · 2026-08-30T14:18:56Z

Created by Roomote. Follow up by mentioning @roomote, in the web UI, or in Discord.

What changed

TaskCompleted now waits until the accepted assistant completion turn is persisted and visible to a fresh extension host. Delayed writes keep completion pending, failed writes use the existing bounded retry policy and suppress the completion event if retries are exhausted, and delegated subtasks persist their completion turn before the child is closed and the parent is reopened.

The PR retains the Alloy 6 safety model and replaces the original unsafe-order characterization with deterministic test-first coverage for delayed, successful, and failed persistence. The restart-persistence scenario now exits immediately after the public event and requires both the user and assistant turns to be restored by a separate extension-host process.

Why this change was made

CodeRabbit's linked-issue check identified that the original characterization did not satisfy issue #1453's production acceptance criteria. Consumers could observe TaskCompleted, restart the extension host, and find that the matching API conversation history was not yet available.

Impact

Consumers can treat TaskCompleted as the restart-safe boundary for the accepted completion turn. An indefinitely delayed write intentionally delays completion rather than weakening that contract, while exhausted retries surface through the existing completion error path without emitting a false success event. There is no UI change; the behavior is covered by the full repository test suite and the two-process fresh-host restart scenario.

Linked work items

Closes #1453

github-actions · 2026-08-30T14:19:07Z

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codecov · 2026-08-30T14:20:16Z

Codecov Report

❌ Patch coverage is 80.00000% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/core/task/Task.ts	83.33%	1 Missing and 2 partials ⚠️
src/core/tools/AttemptCompletionTool.ts	71.42%	2 Missing ⚠️

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edelauna · 2026-08-30T17:20:12Z

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coderabbitai · 2026-08-30T17:20:19Z

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coderabbitai · 2026-08-30T17:20:36Z

📝 Walkthrough

Summary by CodeRabbit

Bug Fixes
- Task completion events are now emitted only after conversation history has been successfully persisted.
- Completion is prevented when persistence repeatedly fails, with the error surfaced through existing error handling.
- Improved reliability for delegated and resumed task completion flows.
- Strengthened end-to-end validation to confirm persisted conversation turns after restart.
Documentation
- Added lifecycle documentation covering completion and history durability policies.
- Documented verification steps, expected results, and known model limitations.

Walkthrough

Adds persistence tracking for assistant history and gates TaskCompleted emission on successful persistence. Adds deterministic regression tests, restart verification, Alloy lifecycle checks, and documentation for the completion contract.

Changes

Completion persistence

Layer / File(s)	Summary
Lifecycle contract and bounded checks `.github/alloy/CompletionPersistence.als`, `.github/alloy/README.md`	Defines completion policies, history durability, lifecycle transitions, bounded assertions, and Alloy verification steps.
Assistant history persistence state `src/core/task/Task.ts`	Tracks assistant-message persistence per request, waits for durable API-history saving, retries failures, and reports exhausted persistence failures.
Completion event gating and validation `src/core/tools/AttemptCompletionTool.ts`, `src/core/task/__tests__/Task.persistence.spec.ts`, `src/core/tools/__tests__/attemptCompletionTool.spec.ts`	Waits for assistant history persistence before delegated and accepted completion events. Tests delayed persistence, event ordering, and retry exhaustion.
Restart and delegated-task validation `apps/vscode-e2e/src/suite/restart-persistence.test.ts`, `packages/types/src/events.ts`, `src/__tests__/history-resume-delegation.spec.ts`, `src/__tests__/nested-delegation-resume.spec.ts`	Requires at least user and assistant history turns after restart, documents `TaskStarted` timing, and updates resumed-task stubs for the persistence wait method.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Merge Risk: 🔵 Low · up to 096c4

The change makes completion notifications wait for durable history, improving restart consistency and suppressing false success after failed persistence. The PR is mergeable with owner awareness that two minor test assertions should be strengthened to verify pending completion and restoration of the expected user and assistant turns.

Sequence Diagram(s)

sequenceDiagram
  participant AttemptCompletionTool
  participant Task
  participant APIHistory
  participant ExtensionHost
  AttemptCompletionTool->>Task: waitForCurrentAssistantMessagePersistence
  Task->>APIHistory: persist assistant conversation history
  APIHistory-->>Task: return persistence result
  Task-->>AttemptCompletionTool: resolve or report failure
  AttemptCompletionTool->>ExtensionHost: emit TaskCompleted

Suggested reviewers: edelauna

🚥 Pre-merge checks | ✅ 5 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	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 3 functions across 8 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.
Regression Evidence	⚠️ Warning	The changed delegated-completion error branch lacks focused coverage. `AttemptCompletionTool.ts:145-150` now catches a rejected `waitForCurrentAssistantMessagePersistence()`, calls `handleError("persi…	Add a focused `attemptCompletionTool` unit test for an active or interrupted child whose `waitForCurrentAssistantMessagePersistence` rejects. Assert that `handleError` receives `"persisting task completion"`, `askFinishSubTaskApproval` and …

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main fix: preventing task history loss when users restart after completion.
Description check	✅ Passed	The description explains the implementation, rationale, behavior for delayed and failed persistence, linked issue, and test coverage. It omits several template sections, including the checklist and a …
Linked Issues check	✅ Passed	The changes address issue `#1453` by delaying TaskCompleted until assistant history persistence completes, handling delayed and failed writes, preserving successful completion, updating delegated comple…
Out of Scope Changes check	✅ Passed	The changes remain focused on completion persistence and restart visibility. The Alloy model, documentation, production code, regression tests, and test stubs support the linked issue objectives. No u…
Trust And Persistence Invariants	✅ Passed	No explicit trust or persistence failure was introduced. `AttemptCompletionTool` now awaits `waitForCurrentAssistantMessagePersistence()` before every public `TaskCompleted` emission, and failed persi…

Full details: Description check

Explanation

The description explains the implementation, rationale, behavior for delayed and failed persistence, linked issue, and test coverage. It omits several template sections, including the checklist and a separate detailed test procedure, but the core information is complete.

Full details: Linked Issues check

Explanation

The changes address issue #1453 by delaying TaskCompleted until assistant history persistence completes, handling delayed and failed writes, preserving successful completion, updating delegated completion flows, and verifying fresh-host restoration with deterministic and end-to-end tests.

Full details: Out of Scope Changes check

Explanation

The changes remain focused on completion persistence and restart visibility. The Alloy model, documentation, production code, regression tests, and test stubs support the linked issue objectives. No unrelated UI or feature changes are present.

Full details: Docstring Coverage

Explanation

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 3 functions across 8 files. (1 skipped: 1 unsupported.)

Full details: Regression Evidence

Explanation

The changed delegated-completion error branch lacks focused coverage. AttemptCompletionTool.ts:145-150 now catches a rejected waitForCurrentAssistantMessagePersistence(), calls handleError("persisting task completion", ...), and returns before approval, parent reopening, or TaskCompleted. The delegation tests only resolve this wait (attemptCompletionTool.spec.ts:515-550), and repository searches found no rejected-wait or matching error assertion. The separate persistence test covers exhausted retries for a standalone completion, not the delegated-child guard. The delayed-success path, direct completion ordering, retry exhaustion, and fresh-host history checks are covered. No Playwright component snapshot is required because this PR has no durable visible UI change.

Resolution

Add a focused attemptCompletionTool unit test for an active or interrupted child whose waitForCurrentAssistantMessagePersistence rejects. Assert that handleError receives "persisting task completion", askFinishSubTaskApproval and reopenParentFromDelegation are not called, and TaskCompleted is not emitted. Keep the existing success-ordering test to cover the normal delegated path.

Full details: Trust And Persistence Invariants

Explanation

No explicit trust or persistence failure was introduced. AttemptCompletionTool now awaits waitForCurrentAssistantMessagePersistence() before every public TaskCompleted emission, and failed persistence routes to handleError without emitting completion. Task.addToApiConversationHistory() resolves the persistence state only after the awaited save result, with bounded retries on failure. The changed path uses the existing saveApiMessages → safeWriteJson atomic temporary-file and rename flow. No changed code executes new unvalidated input, bypasses approval controls, or adds an unreleased timer/listener/resource.

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Commit unit tests in branch fix/model-completion-persistence-176wyz2fscjpe

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🔧 ESLint

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apps/vscode-e2e/src/suite/restart-persistence.test.ts

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

packages/types/src/events.ts

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

src/__tests__/history-resume-delegation.spec.ts

ESLint skipped: missing config or dependency (missing-dependency). The ESLint configuration references a package that is not available in the sandbox.

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zoomote · 2026-08-30T18:06:06Z

Addressed CodeRabbit's linked-issue feedback in 096c4691: TaskCompleted is now restart-safe for top-level and delegated tasks, delayed and failed writes have explicit semantics, and the fresh-host scenario requires restoration of both conversation turns. The full repository suite and the two-process restart test pass.

edelauna · 2026-08-30T18:48:26Z

@CodeRabbit review

coderabbitai · 2026-08-30T18:48:32Z

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Actionable comments posted: 2

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Inline comments:
In `@apps/vscode-e2e/src/suite/restart-persistence.test.ts`:
- Around line 84-85: Strengthen the persistence assertion near
conversationLength by validating that the fresh host restored both the expected
user turn and the accepted assistant completion turn, including their roles or
content. Do not rely on conversationLength >= 2 alone; use the existing
conversation entries or a helper with a contract that verifies those exact
turns.

In `@src/core/task/__tests__/Task.persistence.spec.ts`:
- Line 475: In the unresolved-save test around mockSaveApiMessages, add an
assertion that completionEmitted remains false after saveSettled becomes false
and before saveDeferred is resolved. Preserve the existing assertion that the
save started, then resolve the deferred save and retain the subsequent
completion verification.

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📥 Commits

Reviewing files that changed from the base of the PR and between 68fb953 and 096c469.

📒 Files selected for processing (9)

.github/alloy/README.md
apps/vscode-e2e/src/suite/restart-persistence.test.ts
packages/types/src/events.ts
src/__tests__/history-resume-delegation.spec.ts
src/__tests__/nested-delegation-resume.spec.ts
src/core/task/Task.ts
src/core/task/__tests__/Task.persistence.spec.ts
src/core/tools/AttemptCompletionTool.ts
src/core/tools/__tests__/attemptCompletionTool.spec.ts

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📓 Path-based instructions (15)

Check persistence and lifecycle invariants: awaited atomic writes, rollback or explicit partial-failure behavior, cross-window state consistency, stale listeners/watchers, cancellation, idempotency, and safe restart/resume without lost or d...