Troubleshooting

Errors in Cache restore

To troubleshoot cache restore issues, rerun your workflow with debug logging enabled. Check for any warnings or errors in the restore step that match those described below.

zstd version: null followed by a 404 warning

Each cache entry has a unique version associated with it (See: Cache Version), which is matched during the restore process. The zstd version: null warning indicates that the default compression tool, zstd, is not available in the current environment. Consequently, the action falls back to using gzip compression. (This warning can be ignored if the cache was originally saved using gzip.)

Since all warpbuild runners have zstd available, this warning typically occurs when running the action inside a container that lacks zstd.

To resolve this issue, ensure that the compression tools available in the current environment match those used when the cache was saved. If the cache was saved in a container with zstd and you attempt to restore it in a container without zstd, the restore will fail.