For some "out of disk space" circumstances my Psalm wrote to cache but couldn't do it fully.

When I cleared up the storage, it still failed:

Uncaught Exception: RuntimeException PHP Error: unserialize(): Error at offset 262140 of 262144 bytes in /tools/.composer/vendor-bin/psalm/vendor/vimeo/psalm/src/Psalm/Internal/Provider/ClassLikeStorageCacheProvider.php:145

The cache file itself was corrupted, but this shouldn't interrupt execution, it can just be ignored like it doesn't exits.