Step should not succeed when tar fails with error

Using a simple step to restore the build x cache we encountered an error (below). I believe the issue is that the GitHub cache became corrupt. However actions/cache did not catch the error.

      - name: Cache layers
        uses: actions/cache@v2
        with:
          path: /tmp/.buildx-cache
          key: ${{ runner.os }}-buildx-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-buildx-

So only a warning was printed instead of failing the step:

....
/*stdin*\ : Decoding error (36) : Restored data doesn't match checksum 
/usr/bin/tar: Child returned status 1
/usr/bin/tar: Error is not recoverable: exiting now
Warning: Tar failed with error: The process '/usr/bin/tar' failed with exit code 2

[bishal-pdMSFT]

Btw, there are REST APIs available now to be able to delete a corrupted cache. This can help come out of a situation where a cache is corrupted the only alternative is to update the cache key forcibly.

[bishal-pdMSFT]

Or the action could report whether the cache was successfully restored or not via an output, that way users could decide for themselves whether to proceed or not.

That is already possible with cache-hit output. It is set if a cache has been restored with exact matching key. If it is not set, then it is a good idea to run the install/build steps.

The action should restore the cache completely or not at all.

Agree. Any failure in unarchiving should be handled more cleanly.