perf: cache repeated path canonicalization

[jdx]

Summary

• add a process-local helper for cached successful path canonicalization
• use it in repeated PATH/root comparison paths such as shim lookup, activation, hook-env diffing, and install root checks
• leave freshness-sensitive canonicalization sites such as trust mutation, template filters, lockfiles, and OCI packaging uncached

Context

This is intended as a small prereq for #10019 so shim-directory comparisons can keep symlink-aware canonicalization without repeatedly hitting the filesystem for stable PATH/root entries.

Tests

• cargo check --bin mise
• cargo clippy --bin mise -- -D warnings
• cargo test --bin mise file::

---

Note

Low Risk
Localized performance refactor with intentional non-caching of failures; behavior should match prior symlink-aware comparisons for stable paths.

Overview
Adds process-local caching for successful absolute-path canonicalize results via new canonicalize_cached and canonicalize_or_self helpers in file.rs. Failed canonicalizations are not cached so paths that appear later in the same run still resolve correctly.

Call sites that repeatedly compare stable directories and PATH entries now use the helpers instead of calling canonicalize every time—activation (shim removal and “already in PATH” checks), hook-env PATH deduplication, doctor path-order warnings, shim system fallback lookup, install symlink root checks, trusted config paths, and task cache keys.

Relative paths still canonicalize on each use without entering the cache. Other code paths that need fresh resolution (trust mutations, lockfiles, templates, etc.) are unchanged.

^{Reviewed by Cursor Bugbot for commit cdd7e2c. Bugbot is set up for automated code reviews on this repo. Configure here.}

[gemini-code-assist]

Code Review

This pull request introduces a cached path canonicalization mechanism (canonicalize_cached and canonicalize_or_self) in src/file.rs to optimize repeated filesystem path resolution operations. It refactors direct .canonicalize() calls to use these cached alternatives across several modules, including backend operations, CLI activation, doctor checks, environment hooks, settings, shims, and task helpers. I have no feedback to provide as there are no review comments to assess.

[greptile-apps]

Greptile Summary

This PR introduces a process-local canonicalize_cached helper in src/file.rs that memoises successful fs::canonicalize calls in a Mutex<HashMap>, then threads it through the hot paths in shim lookup, shell activation, hook-env diffing, install-root checks, and task helpers to eliminate redundant filesystem round-trips for stable PATH/root entries.

• src/file.rs: New canonicalize_cached (caches only successes; skips cache for relative paths) and canonicalize_or_self convenience wrapper, following the same double-lock Mutex pattern already used by the existing which cache.
• src/shims.rs: In addition to adopting the cache, the refactor also silently fixes a pre-existing bug — the old code used PathBuf::new() (empty path) as the sentinel for "directory not found" in user_shims/sys_shims, which meant a PATH entry whose fs::canonicalize also failed (returning PathBuf::new() via unwrap_or_default) would incorrectly match and be skipped; the new Option<PathBuf> approach makes the absence case explicit.
• All other call sites (activate.rs, hook_env.rs, doctor/mod.rs, backend/mod.rs, settings.rs, task_helpers.rs): mechanical substitution with no logic changes.

Confidence Score: 5/5

Safe to merge; the change is a well-scoped performance optimisation that also incidentally corrects a subtle empty-path sentinel comparison in the shim fallback path.

All call sites were reviewed. The cache is correctly bounded to successful, absolute-path canonicalisations; failure paths are never cached so paths created later in the same process are handled correctly. The Mutex-double-lock pattern matches the existing which cache in the same file. The shims.rs refactor moves from a fragile PathBuf::new() sentinel to typed Option<PathBuf>, making the logic more correct. No freshness-sensitive sites (trust mutation, lockfile, OCI) were touched.

No files require special attention; src/shims.rs is worth a quick read to confirm the sentinel-fix intent, but the change is clearly correct.

Important Files Changed

Filename	Overview
src/file.rs	Adds canonicalize_cached (process-local Mutex+HashMap cache for successful canonicalizations) and the convenience wrapper canonicalize_or_self; follows the same double-lock pattern used by the existing which cache.
src/shims.rs	Replaces fs::canonicalize + unwrap_or_default with canonicalize_cached; also silently fixes a pre-existing bug where a failed PATH-entry canonicalization could produce PathBuf::new() matching user_shims/sys_shims when those also defaulted to empty paths.
src/cli/activate.rs	Switches path comparisons in shim-removal and PATH checks to use canonicalize_cached/canonicalize_or_self; logic is functionally equivalent and benefits from caching.
src/cli/hook_env.rs	PATH-diffing logic switches four p.canonicalize().ok() calls to canonicalize_cached; semantics unchanged.
src/cli/doctor/mod.rs	Replaces inline lambda with canonicalize_or_self and uses canonicalize_cached as a method-value for and_then; no logic changes.
src/backend/mod.rs	Install-root comparison uses canonicalize_cached; uses ? via Option to preserve the "if canonicalize fails, don't skip" logic from the original code.
src/config/settings.rs	Trusted-path iterator switches to canonicalize_cached; semantics are equivalent for stable config directory roots.
src/task/task_helpers.rs	Thin wrapper canonicalize_path now delegates to canonicalize_or_self, adding process-level caching for task-path cache keys.

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[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.15 x -- echo	20.4 ± 1.4	17.8	27.5	1.00
mise x -- echo	21.2 ± 2.6	18.3	40.6	1.04 ± 0.15

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.15 env	19.7 ± 1.4	17.2	27.7	1.03 ± 0.10
mise env	19.1 ± 1.3	17.0	28.4	1.00

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.15 hook-env	20.1 ± 1.3	17.9	26.8	1.00
mise hook-env	20.3 ± 1.7	18.1	29.1	1.01 ± 0.11

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.5.15 ls	17.9 ± 1.4	14.7	24.4	1.06 ± 0.11
mise ls	16.9 ± 1.2	14.9	22.4	1.00

xtasks/test/perf

Command	mise-2026.5.15	mise	Variance
install (cached)	136ms	138ms	-1%
ls (cached)	61ms	61ms	+0%
bin-paths (cached)	68ms	67ms	+1%
task-ls (cached)	125ms	127ms	-1%