What
File sync now takes a lock before writing, so if you have the same session open in two windows only the first one syncs. The second says so and stays quiet instead of both writing at once.
Details
- The lock is a file under a
writer-locksdirectory keyed to the session's side repository. - If a window's lock is taken over or lost while it held it, sync stops in that window with an explicit message rather than continuing blind.
- If the process stalls long enough to be caught by the interval check, the lock is re-taken and cached state is thrown away rather than assumed to still be valid.
Evidence
Another Claude Code window on this machine is syncing this session's files; this one won't
Strings lifted out of the shipped bundle, so the claim above can be checked against them.