From 26791303f85fdf081823fa4f5fd79bfee270519e Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sat, 23 May 2026 17:50:32 +0000
Subject: [PATCH] Bolt: [performance improvement] Defer PathBuf allocations
 during Tarjan DFS traversal

Co-authored-by: bashandbone <89049923+bashandbone@users.noreply.github.com>
---
 crates/ast-engine/src/tree_sitter/mod.rs     | 10 ++++++----
 crates/flow/src/incremental/invalidation.rs  | 18 ++++++++++--------
 crates/rule-engine/src/rule/mod.rs           |  6 +++++-
 crates/rule-engine/src/rule/referent_rule.rs |  5 +----
 4 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/crates/ast-engine/src/tree_sitter/mod.rs b/crates/ast-engine/src/tree_sitter/mod.rs
index 3762df9..7bd59d1 100644
--- a/crates/ast-engine/src/tree_sitter/mod.rs
+++ b/crates/ast-engine/src/tree_sitter/mod.rs
@@ -553,9 +553,8 @@ impl ContentExt for String {
         let mut bytes = std::mem::take(self).into_bytes();
         let original_len = bytes.len();
         bytes.splice(safe_start..safe_end, full_inserted);
-        *self = Self::from_utf8(bytes).unwrap_or_else(|e| {
-            Self::from_utf8_lossy(&e.into_bytes()).into_owned()
-        });
+        *self = Self::from_utf8(bytes)
+            .unwrap_or_else(|e| Self::from_utf8_lossy(&e.into_bytes()).into_owned());
 
         // We calculate new_end_byte using the difference in the new overall string length
         // to correctly align the end offset, taking any potential replacement bytes from
@@ -791,7 +790,10 @@ mod test {
 
         let tree2 = parse_lang(|p| p.parse(&src, Some(&tree)), &Tsx.get_ts_language())?;
         let fresh_tree = parse(&src)?;
-        assert_eq!(tree2.root_node().to_sexp(), fresh_tree.root_node().to_sexp());
+        assert_eq!(
+            tree2.root_node().to_sexp(),
+            fresh_tree.root_node().to_sexp()
+        );
         Ok(())
     }
 }
diff --git a/crates/flow/src/incremental/invalidation.rs b/crates/flow/src/incremental/invalidation.rs
index da9ac9c..bab368f 100644
--- a/crates/flow/src/incremental/invalidation.rs
+++ b/crates/flow/src/incremental/invalidation.rs
@@ -341,12 +341,14 @@ impl InvalidationDetector {
     /// DFS helper for Tarjan's algorithm
     fn tarjan_dfs(&self, v: &Path, state: &mut TarjanState, sccs: &mut Vec<Vec<PathBuf>>) {
         // Initialize node
+        // Bolt: defer PathBuf allocations during traversal by reusing a single allocation
         let index = state.index_counter;
-        state.indices.insert(v.to_path_buf(), index);
-        state.lowlinks.insert(v.to_path_buf(), index);
+        let v_buf = v.to_path_buf();
+        state.indices.insert(v_buf.clone(), index);
+        state.lowlinks.insert(v_buf.clone(), index);
         state.index_counter += 1;
-        state.stack.push(v.to_path_buf());
-        state.on_stack.insert(v.to_path_buf());
+        state.stack.push(v_buf.clone());
+        state.on_stack.insert(v_buf);
 
         // Visit all successors (dependencies)
         let dependencies = self.graph.get_dependencies(v);
@@ -358,19 +360,19 @@ impl InvalidationDetector {
 
                 // Update lowlink
                 let w_lowlink = *state.lowlinks.get(dep).unwrap();
-                let v_lowlink = state.lowlinks.get_mut(&v.to_path_buf()).unwrap();
+                let v_lowlink = state.lowlinks.get_mut(v).unwrap();
                 *v_lowlink = (*v_lowlink).min(w_lowlink);
             } else if state.on_stack.contains(dep) {
                 // Successor is on stack (part of current SCC)
                 let w_index = *state.indices.get(dep).unwrap();
-                let v_lowlink = state.lowlinks.get_mut(&v.to_path_buf()).unwrap();
+                let v_lowlink = state.lowlinks.get_mut(v).unwrap();
                 *v_lowlink = (*v_lowlink).min(w_index);
             }
         }
 
         // If v is a root node, pop the stack to create an SCC
-        let v_index = *state.indices.get(&v.to_path_buf()).unwrap();
-        let v_lowlink = *state.lowlinks.get(&v.to_path_buf()).unwrap();
+        let v_index = *state.indices.get(v).unwrap();
+        let v_lowlink = *state.lowlinks.get(v).unwrap();
 
         if v_lowlink == v_index {
             let mut scc = Vec::new();
diff --git a/crates/rule-engine/src/rule/mod.rs b/crates/rule-engine/src/rule/mod.rs
index d1d7712..a2433f3 100644
--- a/crates/rule-engine/src/rule/mod.rs
+++ b/crates/rule-engine/src/rule/mod.rs
@@ -246,7 +246,11 @@ impl Rule {
 
     pub fn defined_vars(&self) -> RapidSet<String> {
         match self {
-            Rule::Pattern(p) => p.defined_vars().into_iter().map(|s| s.to_string()).collect(),
+            Rule::Pattern(p) => p
+                .defined_vars()
+                .into_iter()
+                .map(|s| s.to_string())
+                .collect(),
             Rule::Kind(_) => RapidSet::default(),
             Rule::Regex(_) => RapidSet::default(),
             Rule::NthChild(n) => n.defined_vars(),
diff --git a/crates/rule-engine/src/rule/referent_rule.rs b/crates/rule-engine/src/rule/referent_rule.rs
index dd947bc..74d480e 100644
--- a/crates/rule-engine/src/rule/referent_rule.rs
+++ b/crates/rule-engine/src/rule/referent_rule.rs
@@ -27,10 +27,7 @@ impl<R> Clone for Registration<R> {
 
 impl<R> Registration<R> {
     fn read(&self) -> Arc<RapidMap<String, R>> {
-        self.0
-            .read()
-            .unwrap_or_else(|e| e.into_inner())
-            .clone()
+        self.0.read().unwrap_or_else(|e| e.into_inner()).clone()
     }
     pub(crate) fn contains_key(&self, key: &str) -> bool {
         self.read().contains_key(key)