Optimize supplement file lookup with direct tree traversal (#80)

miketheman · claude · web-flow · commit 95f67ad7c69a · 2026-02-05T16:19:20.000Z
Replace O(n) whole-tree iteration with O(1) subtree lookup when finding
supplement files (lockfiles) in the same directory as a manifest.

Before: tree.Files().ForEach() iterated every file in the repository,
then filtered by directory path - O(total files in repo) per manifest.

After: tree.Tree(dir) navigates directly to the target directory, then
iterates only its direct entries - O(files in directory) per manifest.

Performance improvement on a repository with 8619 commits:
- Before: 5:20 (320 seconds)
- After: 12 seconds
- Speedup: ~26x

Also fixes a subtle bug where filepath.Dir() was used (platform-dependent
path separators) instead of explicit "/" (git's path convention), and
removes mutation of the captured `dir` variable inside the ForEach closure.

Co-authored-by: Claude Opus 4.5 &lt;noreply@anthropic.com&gt;
diff --git a/internal/analyzer/analyzer.go b/internal/analyzer/analyzer.go
@@ -578,33 +578,49 @@ func (a *Analyzer) parseSupplementsInDir(tree *object.Tree, dir string) map[supp
 
 	hashes := make(map[supplementKey]string)
 
-	_ = tree.Files().ForEach(func(f *object.File) error {
-		fileDir := filepath.Dir(f.Name)
-		if fileDir == "." {
-			fileDir = ""
+	// Get the target directory's tree directly instead of iterating all files
+	var targetTree *object.Tree
+	if dir == "" || dir == "." {
+		targetTree = tree
+	} else {
+		var err error
+		targetTree, err = tree.Tree(dir)
+		if err != nil {
+			// Directory doesn't exist in this tree
+			return hashes
 		}
-		if dir == "." {
-			dir = ""
+	}
+
+	// Iterate only direct entries in this directory (not recursive)
+	for _, entry := range targetTree.Entries {
+		// Skip subdirectories and non-regular files
+		if !entry.Mode.IsFile() {
+			continue
 		}
-		if fileDir != dir {
-			return nil
+
+		// Build the full path for identification
+		var fullPath string
+		if dir == "" || dir == "." {
+			fullPath = entry.Name
+		} else {
+			fullPath = dir + "/" + entry.Name
 		}
-		if !isSupplementFile(f.Name) {
-			return nil
+
+		if !isSupplementFile(fullPath) {
+			continue
 		}
 
-		result, err := a.parseManifestInTree(tree, f.Name)
+		result, err := a.parseManifestInTree(tree, fullPath)
 		if err != nil || result == nil {
-			return nil
+			continue
 		}
 
 		for _, dep := range result.Dependencies {
 			if dep.Integrity != "" {
 				hashes[supplementKey{dep.Name, dep.Version}] = dep.Integrity
 			}
 		}
-		return nil
-	})
+	}
 
 	return hashes
 }
