Host and container share this checkout through a bind mount but run as
different uids -- 1000 and 0, measured. Whichever writes .ruff_cache or
.import_linter_cache first owns it, and the other is then locked out:
ruff aborts with "Failed to create temporary file: Permission denied" and
test_import_contracts fails the same way, reporting a broken contract that
is in fact perfectly intact.
Point both at build/<tool>-cache-$(id -u). build/ is already 0777 and
gitignored, and this is the mechanism the lint stamp
(build/install-lint-<hash>.stamp) already uses to keep the two environments
apart. Passing --no-cache would have silenced the symptom at the cost of the
cache on every single run.
The pre-existing .ruff_cache and .import_linter_cache are nobody-owned and
cannot be removed without root; they are simply unused from now on.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
kevinveenbirkenbachandClaude Opus 5