Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a significant performance regression introduced by the removal of the aqua bin_paths disk cache. By reintroducing the disk cache and implementing a robust fresh_file invalidation mechanism, the PR aims to restore mise command performance to pre-regression levels while preventing the staleness issues that led to the cache's initial removal. This ensures that mise commands benefit from persistent caching across process invocations without compromising data integrity.

Highlights

• Disk Cache Restoration: The aqua bin_paths.msgpack.z disk cache, previously removed due to staleness issues, has been restored to improve performance.
• Cache Invalidation: Automatic cache invalidation is now implemented using with_fresh_file(tv.install_path()), ensuring the cache is updated when a tool is installed or updated.
• Path Helpers: The PathExt::mount and PathExt::is_empty helper methods were reintroduced to correctly handle relative path operations.

Greptile Summary

Reinstates the aqua backend's bin_paths.msgpack.z disk cache (removed in #8383) with automatic invalidation via with_fresh_file(tv.install_path()). This fixes the ~8-17% performance regression on mise env, mise x, and mise hook-env while preventing the stale cache bugs from #8372.

Key changes:

• Cache now invalidates automatically when install_path mtime changes (during install/update)
• Paths stored as relative paths in cache, reconstructed to absolute on read using new PathExt::mount()
• Follows the same pattern as ExternalPluginCache for asdf backends

Important note: There's still a narrow race window where concurrent mise hook-env during active installation could cache incomplete paths, but the cache self-corrects on the next invocation when it detects the install_path was modified after the cache was created.

Confidence Score: 4/5

• Safe to merge with low risk - well-tested performance fix using established caching patterns
• The implementation correctly follows existing cache patterns (ExternalPluginCache), includes comprehensive testing, and has validated performance improvements. Minor theoretical race condition during concurrent install exists but self-corrects automatically
• No files require special attention - both changes are straightforward

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[list_bin_paths called] --> B{Cache exists?}
    B -->|No| E[Compute paths]
    B -->|Yes| C{Cache fresh?}
    C -->|Yes| D[Return cached paths]
    C -->|No| E
    E --> F[Get package from registry]
    F --> G[Compute srcs]
    G --> H[Filter existing paths]
    H --> I[Strip install_path prefix]
    I --> J[Store relative paths in cache]
    J --> K[Mount paths back to absolute]
    K --> L[Return paths]
    
    M[Installation starts] --> N[remove install_path]
    N --> O[install_path mtime changes]
    O --> P[Next list_bin_paths call]
    P --> Q{Cache older than install_path?}
    Q -->|Yes| R[Cache stale - recompute]
    Q -->|No| S[Cache fresh - use it]

_{Last reviewed commit: 8019d04}

Hyperfine Performance

mise x -- echo

mise env

mise hook-env

mise ls

xtasks/test/perf