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Are your file paths absolute or relative? Always prefer relative paths for better portability.

"Cache flapping"—where the cache is constantly invalidated—isn't just annoying; it's expensive. In a large organization, fixing a 10% cache miss rate can save thousands of dollars in compute credits and hundreds of engineering hours per month. Conclusion

You typically reach for debugging flags when you encounter two specific scenarios: debug-action-cache

If you're compiling binaries, ensure you strip timestamps from the output, as these will change the file hash even if the code is identical. The Cost of Ignoring Cache Issues

Two different machines running the exact same code produce different output hashes, leading to "cache poisoning." How to Debug the Cache: Common Strategies Are your file paths absolute or relative

Before diving into debugging, it’s essential to understand what we’re fixing. Action caching stores the outputs of specific build steps (actions) based on their inputs. The logic is simple:

While different tools have different specific commands, the process of "debugging the action cache" generally follows these steps: 1. Inspecting Input Digests In a large organization, fixing a 10% cache

This exposes the communication between the runner and the remote cache storage, showing you if the network is failing or if the key lookup is returning a "404 Not Found." The "Cache-Hit" Checklist

In systems like Bazel, you can use flags like --execution_log_json_file . This allows you to see the exact metadata sent to the cache. You can compare logs from two different builds to see which file or environment variable caused the discrepancy. 2. Identifying "Dirty" Environment Variables