Persist Pi sessions by GSD session ID

[glittercowboy]

What

Daemon Pi task execution passes a stable local Pi session file for each GSD session.

Why

Pi requires --session <path> to preserve conversation context across spawned task processes. The GSD session ID is the stable local key for that conversation.

How

• Builds a Pi session file path under ~/.gsd-cloud/pi-sessions/<session-id>.jsonl.
• Creates the Pi session directory with user-only permissions.
• Passes that path through pi.Options.ResumeSession so the Pi CLI runs with --session.
• Keeps Pi synthetic result session IDs out of the cloud-facing Claude session field.

Verification

• go test ./internal/session -run 'TestPiSessionFileForSessionUsesGSDSessionID|TestActorPiExecutorUsesPersistentSessionFile|TestHandleResultDoesNotPersistPiSyntheticSession'
• go test ./internal/session ./internal/pi
• go test ./...

Post-merge

Daemon runtime behavior changes require a daemon release tag and release workflow before installed machines receive the fix.

Summary by CodeRabbit

Release Notes

• New Features

  • PI executor now persists and resumes sessions across invocations, enabling continuous progress tracking.

• Tests

  • Added test coverage for session persistence and resumption functionality.

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

📝 Walkthrough

Walkthrough

The changes implement session resumption for the PI executor by introducing a new session persistence helper function that derives per-session file paths, modifying the PI execution path to compute and pass the resumption file to the executor, and adding comprehensive test coverage for the session storage behavior.

Changes

Cohort / File(s)	Summary
Session Resumption Implementation internal/session/actor.go	Derives per-session resume file path using piSessionFileForSession, adds early error handling, and passes the computed file to pi.Options via ResumeSession field to enable session resumption behavior.
Session File Path Helpers internal/session/pi_session.go	Introduces piSessionFileForSession function that validates session ID, resolves user home directory, ensures ~/.gsd-cloud/pi-sessions directory exists with restrictive permissions, and returns sanitized .jsonl filename; includes safePiSessionFilename for filename sanitization.
Session Resumption Tests internal/session/actor_test.go	Adds test utilities to simulate PI process and capture command-line arguments, verifies session file path computation using GSD SessionID, and ensures --session flag is correctly passed to PI binary while --no-session is absent.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• gsd-build/daemon#42: Directly modifies the same PI session resumption behavior in internal/session/actor.go but removes ResumeSession to avoid resuming synthetic PI sessions.

Poem

🐰 A rabbit hops through session files,
Deriving paths with worthy wiles,
PI executor now persists with grace,
Sessions saved in their rightful place!
~/.gsd-cloud/ blooms so bright,
Each .jsonl a fluffy delight! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Persist Pi sessions by GSD session ID' accurately and specifically describes the main change: implementing session persistence for the Pi CLI using GSD session IDs as the stable key.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/pi-session-persistence

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}