refactor(stacktrace): remove unnecessary locking from segmentPrefixTrie

internal/stacktrace/trie.go

@@ -145,9 +145,14 @@ func (t *prefixTrie) Clear() {
 // segmentPrefixTrie is a path segment-based trie optimized for "/" delimited paths.
 // It stores path segments (e.g., "github.com", "DataDog") as nodes instead of individual characters,
 // providing better memory efficiency and potentially faster lookups for module paths.
+//
+// Concurrency: This trie follows a write-once-read-many (WORM) pattern where all writes
+// occur during package initialization (init function) before any concurrent access begins.
+// After initialization, the trie is effectively immutable and can be safely read by multiple
+// goroutines without synchronization.
 type segmentPrefixTrie struct {
 	root *segmentTrieNode
-	mu   sync.RWMutex
+	// No mutex needed - structure is immutable after init()
 }
 
 // segmentTrieNode represents a single path segment node in the trie
@@ -165,15 +170,13 @@ func newSegmentPrefixTrie() *segmentPrefixTrie {
 	}
 }
 
-// Insert adds a prefix to the segment trie
+// Insert adds a prefix to the segment trie.
+// This method should only be called during initialization before any concurrent access.
 func (t *segmentPrefixTrie) Insert(prefix string) {
 	if prefix == "" {
 		return
 	}
 
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
 	node := t.root
 	start := 0
 
@@ -197,14 +200,12 @@ func (t *segmentPrefixTrie) Insert(prefix string) {
 }
 
 // HasPrefix checks if the given string has any of the prefixes stored in the segment trie.
+// Safe for concurrent use after initialization.
 func (t *segmentPrefixTrie) HasPrefix(s string) (found bool) {
 	if s == "" {
 		return false
 	}
 
-	t.mu.RLock()
-	defer t.mu.RUnlock()
-
 	node := t.root
 	start := 0
 
@@ -230,11 +231,9 @@ func (t *segmentPrefixTrie) HasPrefix(s string) (found bool) {
 	return node.isEnd
 }
 
-// InsertAll adds multiple prefixes to the segment trie in a single operation
+// InsertAll adds multiple prefixes to the segment trie in a single operation.
+// This method should only be called during initialization before any concurrent access.
 func (t *segmentPrefixTrie) InsertAll(prefixes []string) {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
 	for _, prefix := range prefixes {
 		if prefix == "" {
 			continue
@@ -263,11 +262,9 @@ func (t *segmentPrefixTrie) InsertAll(prefixes []string) {
 	}
 }
 
-// Size returns the number of prefixes stored in the segment trie
+// Size returns the number of prefixes stored in the segment trie.
+// Safe for concurrent use after initialization.
 func (t *segmentPrefixTrie) Size() int {
-	t.mu.RLock()
-	defer t.mu.RUnlock()
-
 	return t.countSegmentPrefixes(t.root)
 }
 
@@ -289,11 +286,9 @@ func (t *segmentPrefixTrie) countSegmentPrefixes(node *segmentTrieNode) int {
 	return count
 }
 
-// Clear removes all prefixes from the segment trie
+// Clear removes all prefixes from the segment trie.
+// This method should only be called during initialization before any concurrent access.
 func (t *segmentPrefixTrie) Clear() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
 	t.root = &segmentTrieNode{
 		children: make(map[string]*segmentTrieNode),
 	}