Five routes changed the linked-cases registry: link, unlink, rename, and a
create or clone into a custom folder. Each read the file, checked it and wrote
it back on its own, so two requests that both read before either wrote lost
an entry. Two clones that claimed one name and finished together both passed
the name check, both answered success, and the later write replaced the
earlier entry. The same race made "a name linked while the clone ran is a
409" in test/routes/case-clone-custom-folder.test.ts fail about half the time.
- New src/web/linked-cases-writer.ts, mutateLinkedCases(), shaped like
mutateSettingsFile(): mutations run one at a time, each write is a temp
file renamed over the registry (through a symlink, keeping its mode), and
a file that is not a JSON object is refused (409 CONFLICT) instead of being
read as {} and overwritten.
- All five writers go through it, with their name checks inside the
callback, so exactly one of two requests for one name wins. Rename also
re-checks that the old name still points at the old folder, and drops its
manual registry undo, since a failed write no longer changes the file.
- Tests: test/linked-cases-writer.test.ts (writer behaviour, and concurrent
link/unlink through the routes with slowed writes, which fail on the old
code). Tests that forced a failed registry write with chmod 444 or a
directory now inject the failure at the rename, or expect the refusal.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Codeman maintainer
5929584ea4