perf: replace map[string]bool sets with map[string]struct{} across hot paths by jeduden · Pull Request #679 · jeduden/mdsmith

jeduden · 2026-06-21T20:34:06Z

Summary

Performance audit against docs/development/high-performance-go.md, which states: "map[K]struct{} for sets — zero-byte value type." Five hot-path locations and two related cleanup sites used map[string]bool as presence-only sets, paying one wasted byte per entry and one wasted bool comparison per read.

Fixes (5 hot-path locations + 2 follow-ons)

1. internal/rules/catalog/rule.go — include-graph traversal (hottest path)
fileIncludesTarget / fileIncludesTargetAbs and their recursive workers scanIncludesForTarget / scanIncludesForTargetAbs carried visited map[string]bool through every per-file catalog directive evaluation. Changed to map[string]struct{}. DFS delete(visited, resolved) backtracking preserved.

2. internal/lint/runcache.go — LSP invalidation cycle guard
Invalidate → invalidate → invalidateDependents passed a map[string]bool cycle guard on every LSP file-edit event. Changed to map[string]struct{}.

3. internal/config/kind_extends.go + validate.go — extends chain walkers
Three chain-walking functions (KindExtendsChain, extendsChainSchemas, validateKindExtends) used map[string]bool for cycle detection. Changed to map[string]struct{}. KindExtendsChain also fixed to return nil instead of []string{} on empty result (project nil-not-empty convention). Two intermediate chain := []string{} accumulators changed to var chain []string (defers first allocation to first append).

4. internal/config/merge.go + provenance.go — per-file kind resolution
EffectiveKinds, resolveEffectiveKinds, resolveKindsWithSources, and allRuleNames de-dup sets changed from map[string]bool to map[string]struct{}.

5. internal/lint/files.go — CLI file deduplication
ResolveFilesWithOpts seen-set changed to map[string]struct{}.

6. pkg/mdsmith/workspace.go — memFS directory enumeration
memFS.dirEntries seen-set changed. Also fixed a short-circuit evaluation bug in the conversion: the if init; cond form if _, ok := seen[name]; name != "" && !ok ran the map probe before the guard (init always executes in Go's if init; cond form). Restored guard-first order with nested if blocks.

TDD

Red test: TestKindExtendsChain_EmptyNameReturnsNil (fails against old []string{} return; passes after var out []string)
Red state: Updating catalog test call sites to map[string]struct{} before updating function signatures produces type-mismatch compile errors; fixing signatures restores green
Workspace test: TestMemFSDirEntriesIgnoresEmptySegment added to document and pin the empty-name-segment guard in dirEntries

Code review passes

Three --max code review passes were run:

Pass 1: Found confirmed bug (short-circuit inversion in workspace.go) → fixed in 9b0fa79
Pass 2: No new confirmed correctness bugs
Pass 3: Found chain := []string{} allocation (confirmed), allRuleNames not converted (plausible), missing workspace test (confirmed TDD gap) → fixed in ef818c0

Test plan

go test ./... — all packages green
go build ./... — clean build
Verify internal/integration/alloc_budget_test.go passes (allocation budget gate)
Run go run ./cmd/mdsmith check . to confirm markdown lints clean

🤖 Generated with Claude Code

https://claude.ai/code/session_01QjbjBieiWMBKURdKVNnPvy

Generated by Claude Code

codecov · 2026-06-21T20:34:40Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.62%. Comparing base (ff7ab4d) to head (6d89652).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

Components	Coverage Δ
Go	`98.61% <100.00%> (+<0.01%)`	⬆️
TypeScript	`99.54% <ø> (ø)`

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jeduden · 2026-06-22T11:41:41Z

🟢 Merge Queue — picked up

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jeduden · 2026-06-22T11:42:31Z

⚠️ Merge Queue — merge conflict

This PR could not be merged into the batch branch without conflicts with main or another queued PR.

Next: Rebase onto or merge main into your branch, resolve conflicts, push, then re-add the queue label.

…y returns Five hot-path locations used map[string]bool as a visited/dedup set, storing only true values and paying one wasted byte per entry. Per the high-performance Go guidelines (docs/development/high-performance-go.md), pure sets must use map[string]struct{} — zero-byte value type. - catalog/rule.go: scanIncludesForTarget + scanIncludesForTargetAbs visited sets (called per-file per catalog directive, hot check path) - lint/runcache.go: Invalidate/invalidate/invalidateDependents cycle guard (called on every LSP file edit) - config/kind_extends.go + validate.go: validateKindExtends, extendsChainSchemas, KindExtendsChain visited sets; KindExtendsChain also fixed to return nil instead of []string{} for empty results (project return-nil convention) - config/merge.go + provenance.go: EffectiveKinds, resolveEffectiveKinds, resolveKindsWithSources dedup sets (called per-file during engine run) - pkg/mdsmith/workspace.go: memFS.dirEntries dedup set (workspace walk) - lint/files.go: ResolveFilesWithOpts dedup set (CLI file resolution) Red: TestKindExtendsChain_EmptyNameReturnsNil (wrong return type) + type-mismatch compile errors in catalog tests (wrong visited type). Green: all tests pass after signature + call-site updates. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QjbjBieiWMBKURdKVNnPvy

…check The previous commit changed `if name != "" && !seen[name]` to `if _, ok := seen[name]; name != "" && !ok`. In Go's `if init; cond` form the init statement always executes before the condition, so the map probe ran unconditionally — even when `name == ""` — reversing the original short-circuit semantics. Restore the guard-first order by nesting the membership check inside an explicit `if name != ""` block, matching the original evaluation order and preventing any wasted probe on empty segment paths. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QjbjBieiWMBKURdKVNnPvy

Third code-review pass found three issues: 1. validate.go and kind_extends.go: `chain := []string{}` allocates an empty backing array on every call. `var chain []string` (nil slice) defers the first allocation to the initial append, saving one heap allocation on every call where the loop never appends (kinds without an extends: chain in validateKindExtends, or when the extends chain has no schemas in extendsChainSchemas). 2. provenance.go: `allRuleNames` was the last `map[string]bool` presence set in the file not converted by the previous commit. Changed to `map[string]struct{}` for consistency with the surrounding code. 3. workspace_test.go: Add TestMemFSDirEntriesIgnoresEmptySegment to document and pin the empty-name-segment guard in memFS.dirEntries. A key with a double-slash segment (e.g. "a//b.md") produces an empty first component after stripping the directory prefix; the nested-if guard introduced in 9b0fa79 must check `name != ""` before the seen-map probe. The test constructs memFS directly (bypassing NewMemWorkspace path.Clean) to exercise this path. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01QjbjBieiWMBKURdKVNnPvy

jeduden · 2026-06-22T11:49:01Z

🟢 Merge Queue — picked up

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jeduden · 2026-06-22T11:49:22Z

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Merged into batch branch merge-queue/batch-679-1782128941. View CI run.

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jeduden · 2026-06-22T11:54:14Z

✅ Merge Queue — merged

This PR landed on main via commit cbd42a3. CI run that validated the merge.

Next: Done — nothing more to do here.

jeduden marked this pull request as ready for review June 22, 2026 11:35

jeduden added queue Add to a PR to enqueue it queue:active Applied automatically when a PR is in an active batch and removed queue Add to a PR to enqueue it labels Jun 22, 2026

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claude added 3 commits June 22, 2026 11:42

jeduden force-pushed the claude/kind-darwin-r97wed branch from ef818c0 to 6d89652 Compare June 22, 2026 11:44

jeduden added queue Add to a PR to enqueue it and removed queue:failed Applied automatically when CI fails or merge conflict occurs labels Jun 22, 2026 — with Claude

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jeduden merged commit cbd42a3 into main Jun 22, 2026
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perf: replace map[string]bool sets with map[string]struct{} across hot paths - #679

perf: replace map[string]bool sets with map[string]struct{} across hot paths#679
jeduden merged 3 commits into
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jeduden commented Jun 21, 2026

Summary

Fixes (5 hot-path locations + 2 follow-ons)

TDD

Code review passes

Test plan

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