WarpBuild Cache Restore Not Working: How to Debug
If WarpBuild's cache is not restoring, the fastest path is debug logging and a version check. Here is the documented way to diagnose it.
The WarpBuilds/cache action is a drop-in replacement for actions/cache, so most restore problems are the same class of issue you would see with the GitHub cache: key mismatches, missing entries, or a stale action version. WarpBuild's caching docs give a specific debugging path. This page walks through it. Confirm current guidance in WarpBuild's caching docs.
Turn on debug logging first
According to WarpBuild's caching docs, the recommended first step when a cache restore fails is to rerun your workflow with debug logging enabled and inspect the restore step for warnings or errors. In GitHub Actions you enable this by setting the ACTIONS_STEP_DEBUG secret (or repository setting) to true. The debug output usually shows the exact cache key looked up and whether an entry matched.
Upgrade the cache action
WarpBuild's docs note that using WarpBuilds/cache versions older than v1.4.5 may cause issues. If you pinned an older version, bump it to the latest v1 release before deeper debugging, since the problem may already be fixed upstream.
Check keys and compression consistency
Because WarpBuilds/cache mirrors actions/cache, restore only hits when the key (or a restore-key prefix) matches a previously saved entry. Confirm the key inputs are identical between the save and restore jobs. Also confirm compression is consistent: a save that used zstd and a restore in an environment that fell back to gzip (see the zstd version: null warning) can produce mismatches. Align both and retry.
Consider GitHub native cache
WarpBuild's own docs note that GitHub now offers native unlimited caching, which WarpBuild recommends as the most seamless experience for many users. If your caching needs are standard, switching back to actions/cache may remove the issue entirely. Reserve the WarpBuild cache for advanced cases where it clearly helps, and verify current guidance in WarpBuild's docs.