gui.git, gui.helpers and gui.State are all replaced on a repo switch,
which runs on the UI thread. The background fetch and the external-
change poller read them from their own goroutines, racing the
reassignment. This race can't show up in the integration suite, which
doesn't enable the background routines, so no -race run will ever flag
it; it can only bite real users who switch repos while a background
fetch or poll is in flight.
Capture the objects a routine iteration needs in a single blocking
UI-thread hop before using them, the same pattern the refresh's input
capture uses. For the fetch this has two welcome side effects: the
fetch, the post-fetch refresh's generation baseline, and the recorded
fetch time now all refer to the same repo (the old comment documented
the timestamp's mismatch as a known, unguarded race), and the git
instance the fetch runs through is pinned to that repo's directory, so
a switch mid-fetch can no longer direct in-flight work at the new repo.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>