Caching

Mutagoph caches mutation results to skip unchanged mutations on subsequent runs.

How It Works

The cache stores results based on:

• Mutation ID
• Source file content hash
• Test file content hashes

If none of these change, the cached result is used.

Usage

# Enable caching (default)
mutagoph run --cache

# Disable caching
mutagoph run --cache=false

# Specify cache directory
mutagoph run --cache-dir /tmp/mutagoph-cache

# Clear cache before running
mutagoph run --clear-cache

Cache Location

Default: ~/.cache/mutagoph

The cache directory contains:

• Memory cache (in-process, for repeated mutations)
• Disk cache (persistent, survives restarts)

Cache Statistics

When caching is enabled, statistics are shown:

Cache: 142 entries (1.2 MB)

When to Clear Cache

Clear the cache when:

• Test logic changes but test files don’t
• Build configuration changes
• Dependency versions change
• Experiencing unexpected results

mutagoph run --clear-cache

CI Caching

For CI, cache the mutagoph cache directory between runs:

# GitHub Actions
- name: Cache mutagoph results
  uses: actions/cache@v4
  with:
    path: ~/.cache/mutagoph
    key: mutagoph-$-$
    restore-keys: |
      mutagoph-$-

Performance Impact

Caching can provide significant speedups:

• First run: Full execution
• Subsequent runs: Only changed mutations tested
• Typical speedup: 10-100x for incremental changes