---
phase: 25-file-system
plan: "06"
subsystem: api
tags: [git, versioning, file-history, execFile, child_process]

# Dependency graph
requires:
  - phase: 25-01
    provides: chatFileService, chatFileRoutes, StorageService integration
  - phase: 25-00
    provides: chat_files DB schema, ChatFile shared types

provides:
  - gitFileService with ensureRepo, commitFile, getLog using safe execFile
  - GET /files/:fileId/history endpoint returning git log entries
  - Git commit on every file upload (non-blocking fire-and-forget)
  - ChatFileHistoryEntry shared type

affects: [25-file-system, any plan using file version history]

# Tech tracking
tech-stack:
  added: [node:child_process execFile, node:util promisify]
  patterns: [fire-and-forget git commit after upload, execFile array args for shell-injection safety]

key-files:
  created:
    - server/src/services/git-file-service.ts
  modified:
    - server/src/routes/chat-files.ts
    - packages/shared/src/types/chat.ts
    - packages/shared/src/index.ts
    - .planning/REQUIREMENTS.md

key-decisions:
  - "Used execFile (not exec) for all git commands — array-based args prevent shell injection"
  - "Git commit is fire-and-forget (.catch(() => {})) so upload response is not blocked"
  - "History route placed before /content route to prevent Express /files/:fileId/* ambiguity"
  - "resolveDefaultStorageDir() used to find storage root — same path LocalDiskProvider uses"

patterns-established:
  - "gitFileService: factory function returning interface with ensureRepo/commitFile/getLog"
  - "ensureRepo lazily initializes git repo on first use — idempotent via .git dir check"

requirements-completed: [FILE-09, FILE-10]

# Metrics
duration: 5min
completed: 2026-04-01
---

# Phase 25 Plan 06: Git File Versioning Summary

**Git versioning layer added to file uploads: gitFileService wraps git CLI with safe execFile, every upload creates a commit, GET /files/:fileId/history exposes git log**

## Performance

- **Duration:** 5 min
- **Started:** 2026-04-01T21:59:30Z
- **Completed:** 2026-04-01T22:04:30Z
- **Tasks:** 2
- **Files modified:** 5

## Accomplishments
- Created gitFileService with ensureRepo (lazy git init), commitFile (add+commit via execFile), getLog (parse git log output)
- Wired git commit into POST /conversations/:id/files upload flow as non-blocking fire-and-forget
- Added GET /files/:fileId/history endpoint returning paginated git log entries (max 100)
- Added ChatFileHistoryEntry interface to shared types and exported from shared package index

## Task Commits

Each task was committed atomically:

1. **Task 1: Create gitFileService and ChatFileHistoryEntry type** - `eb954635` (feat)
2. **Task 2: Wire git commits into upload flow and add history endpoint** - `6ba745b9` (feat)

**Requirements metadata:** `637ecc74` (chore: mark FILE-09 and FILE-10 complete)

## Files Created/Modified
- `server/src/services/git-file-service.ts` - Git service with ensureRepo/commitFile/getLog methods
- `server/src/routes/chat-files.ts` - Added git import, storageDir, gitSvc, fire-and-forget commit, /history route
- `packages/shared/src/types/chat.ts` - Added ChatFileHistoryEntry interface
- `packages/shared/src/index.ts` - Exported ChatFileHistoryEntry
- `.planning/REQUIREMENTS.md` - Marked FILE-09 and FILE-10 as Complete

## Decisions Made
- Used `execFile` (promisified from `node:util`) instead of `exec` — array args cannot be shell-injected even if objectKey contained special chars
- Git commit is fire-and-forget (`gitSvc.commitFile(...).catch(() => {})`) — upload response sent immediately, git tracking happens asynchronously
- History endpoint placed before `/files/:fileId/content` so Express route matching finds `/history` before falling through to `:fileId` catch-all patterns
- Used `resolveDefaultStorageDir()` from `home-paths.ts` — the exact same path construction that `LocalDiskProvider` uses for its `root` directory

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered
- Worktree was on a different branch (`worktree-agent-afd26110`) without phase-25 prerequisite files. Resolved by checking out required files from `gsd/phase-25-file-system` branch before applying plan 06 changes.

## User Setup Required
None - no external service configuration required.

## Next Phase Readiness
- Git versioning infrastructure complete for FILE-09 and FILE-10 requirements
- gitFileService ready for reuse by any future plan needing git tracking on storage files
- History endpoint available at GET /files/:fileId/history?limit=N

---
*Phase: 25-file-system*
*Completed: 2026-04-01*