Commit d94f2f05 dropped the GIT_OPTIONAL_LOCKS=0 env var that we used
to set on every git command, and re-added lock suppression only as a
--no-optional-locks flag on the background files refresh. The intent
was sound — a foreground `git status` should persist git's refreshed
stat-cache — but the change was too broad: it stopped suppressing
optional locks for every other command too.
The one that bites is the main-view diff. When a folder containing
submodules is selected, we render `git diff --submodule -- <dir>`, and
`--submodule` makes git run `git status` inside each submodule to
describe its "modified" state. That status now grabs the submodule's
index.lock. It runs as a PTY task on its own goroutine, so it races
any submodule-mutating action the user triggers — e.g. resetting a
submodule runs `git -C <submodule> stash`, which then fails with
"index.lock: File exists". This is what made submodule/reset_folder
flaky. `git status` is in fact the only command that takes the
optional lock, but the env var also covered its use inside `git diff
--submodule`, inside PTY-run commands, and inside git's own submodule
child processes — none of which a per-command flag reaches cleanly.
Invert the polarity to match how it worked before d94f2f05: the git
command builder disables optional locks on every command by default,
and the single command that benefits from taking the lock — the
foreground files refresh — opts back in. This restores the original
contention avoidance (including against the user's terminal git) while
keeping d94f2f05's stat-cache-persistence win for the foreground
refresh.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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