Debug-action-cache Exclusive Jun 2026

- name: Generate cache key simulation id: sim run: | echo "hash=$(sha256sum package-lock.json | cut -d' ' -f1)" >> $GITHUB_OUTPUT

Your hashFiles('requirements.txt') changed (maybe a whitespace change), causing the exact key to miss. The restore key Linux-pip- matched a cache from the staging branch instead of main .

debug-cache: runs-on: ubuntu-latest steps: - name: Restore cache debug id: cache-restore uses: actions/cache/restore@v3 with: path: node_modules key: $ runner.os -node-$ hashFiles('package-lock.json') restore-keys: | $ runner.os -node- - name: Show cache status run: | echo "Cache hit: $ steps.cache-restore.outputs.cache-hit " if [ -d node_modules ]; then ls -la node_modules; fi

A previous broken build successfully saved its incomplete or broken dependencies into the cache storage, causing all future runs to pull corrupted files.

Understanding how to misses is crucial for maintaining efficient CI/CD systems and fast local development. This article explores why cache misses occur, how to identify them, and how to debug the action cache in Bazel. 1. What is the Bazel Action Cache? debug-action-cache

(Replace cache_id with the ID string retrieved from the list command above). 4. Best Practices for Bulletproof Action Caching

Or run a manual workflow with:

bazel build //target --execution_log_binary_file=/tmp/exec.log Use code with caution.

Append a version suffix to your cache key in your YAML file (e.g., - name: Generate cache key simulation id: sim

bazel build src/tools/execlog:parser bazel-bin/src/tools/execlog/parser --log_path=/tmp/exec.log > /tmp/exec.txt Use code with caution.

Look at:

Common debugging scenarios:

If your cache keys are not deterministic—meaning they change unexpectedly between runs—you will never get a cache hit. The debug logs are invaluable here. Understanding how to misses is crucial for maintaining

The debug-action-cache philosophy is evolving into . Instead of raw [debug] lines, you will soon see JSON logs you can pipe into jq .

In early 2024, actions/cache@v4 introduced significant changes. Debugging V4 requires new flags.

A debug-action-cache log says: