code-go-gitlisted

# code-go-git Idiomatic review checklist for go-git v5 concurrent access patterns. ## MUST FIX 1. [SAFETY] `*git.Repository` is NOT goroutine-safe — a per-repo `sync.Mutex` (not `sync.RWMutex`) is required for all access. Issue #773 is open as of v5.18. 2. [SAFETY] The packfile `MemoryIndex` has a confirmed concurrent-map crash (`fatal error: concurrent map read and map write`) triggered by concurrent `repo.Log()` / `CommitObject` on the same repo. Issue #1121, June 2024, unfixed in v5.x. 3. [SAFETY] `repo.Log()`, `CommitObject()`, and all iterator types are NOT safe to call concurrently on the same `*git.Repository`. 4. [CONCURRENCY] `repo.Worktree()` / `wt.Status()` wraps the same underlying object storage — calling concurrently on the same repo is unsafe. 5. [CONCURRENCY] The per-repo mutex must cover the **full iterator lifetime**, not just the initial API call. Iterators lazily read from shared object storage on each `Next()` — releasing the lock between obtaining an iterator and exhausting it is a data race. 6. [CONCURRENCY] `sync.RWMutex` does NOT help — go-git "read" operations mutate internal maps (object cache, MemoryIndex). Use `sync.Mutex` only. 7. [SAFETY] v5.17.0 added extension validation: `git.PlainOpen` now returns errors for repos with unsupported extensions. Errors from `PlainOpen` must propagate; never store a nil repo. 8. [ANTI-PATTERN] Never cache a `CommitIter` or `ObjectIter` across calls — iterators hold internal cursor state over shared storage. C