Summary of Changes

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This pull request addresses a critical bug where system-wide installations of tools were not correctly generating runtime symlinks, leading to potential usability issues for users relying on shared or system-level tool management. The changes ensure that mise now properly manages symlinks across all configured installation paths, improving consistency and reliability for both user and system-level tool versions.

Highlights

• System Install Symlink Fix: Resolved an issue where mise install --system failed to create runtime symlinks (e.g., latest, partial version aliases) in system or shared installation directories.
• Enhanced Symlink Generation Logic: The runtime_symlinks::rebuild() function was updated to scan all relevant install directories (user, shared, and system) and generate symlinks based on the versions actually present in each specific directory, rather than relying solely on the backend's default installs path.
• New End-to-End Test: Added a new end-to-end test (test_install_system) to verify that mise install --system correctly creates symlinks in the system install directory, and that user-specific symlinks remain unaffected.

Greptile Summary

This PR fixes mise install --system failing to create runtime symlinks (latest, partial version aliases) in shared/system install directories. Previously, runtime_symlinks::rebuild() only created symlinks under backend.ba().installs_path (the user dir); versions installed in system/shared dirs got no symlinks at all.

Key changes:

• rebuild() now collects all relevant install roots for each backend: the user dir plus any shared/system dirs from env::shared_install_dirs(). Each directory is processed independently.
• A new rebuild_symlinks_in_dir() helper encapsulates the per-directory logic, replacing the inline loop that only operated on the backend's primary path.
• installed_versions_in_dir() replaces installed_versions() (which delegated to the backend): it scans the directory directly for real (non-symlink, non-incomplete) version subdirectories, ensuring each dir only gets symlinks for versions present in that dir.
• Permission errors (EACCES, EROFS) from shared/system dir processing are caught via is_permission_error() and logged as warnings rather than aborting the install. The user dir continues to propagate errors normally.
• A focused e2e regression test installs different tool versions to user and system dirs and verifies each gets its own correct latest symlink.

The all three concerns from prior reviews — permission propagation, EROFS handling, and ReadOnlyFilesystem MSRV compatibility — are fully addressed in this revision (MSRV is 1.88, well above Rust 1.83 where ErrorKind::ReadOnlyFilesystem was stabilized). The remaining redundant sort inside installed_versions_in_dir (versions sorted there and again in list_symlinks_for_dir) is harmless but was noted in a previous review thread.

Confidence Score: 4/5

• Safe to merge with minor housekeeping remaining; the fix is correct and all prior review concerns are addressed.
• All three concerns raised in prior review rounds (permission-error propagation from shared dirs, EROFS not caught, ReadOnlyFilesystem MSRV gap) are fully resolved. The core logic — scanning each install root independently and tolerating permission failures on non-user dirs — is sound. The e2e regression test directly exercises the bug scenario. The one remaining nit (redundant sort) is harmless and was already flagged in a prior thread; it doesn't affect correctness. No new logic or security issues were found.
• No files require special attention; src/runtime_symlinks.rs is the critical path but the changes are well-scoped.

Important Files Changed

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[rebuild called] --> B[for each backend]
    B --> C[Collect installs dirs\nuser dir + shared_install_dirs]
    C --> D[Process user dir\nrebuild_symlinks_in_dir?]
    D -->|error| E[propagate error]
    D -->|ok| F[Process each shared/system dir\nrebuild_symlinks_in_dir?]
    F -->|permission error| G[warn + skip]
    F -->|other error| H[propagate error]
    F -->|ok| I[continue]

    subgraph rebuild_symlinks_in_dir
        J[list_symlinks_for_dir\nversions from dir scan] --> K[for each symlink\ncreate/update]
        K --> L[remove_missing_symlinks_in_dir\nclean dangling symlinks]
    end

    D & F --> rebuild_symlinks_in_dir

_{Reviews (3): Last reviewed commit: "fix: restore semver sort for installed v..." | Re-trigger Greptile}

Hyperfine Performance

mise x -- echo

mise env

mise hook-env

mise ls

xtasks/test/perf