From d61b020b5556ef7adf818eb7c411d2148e40ae31 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 24 Jun 2026 01:16:43 +0000
Subject: [PATCH] Optimize diffTests by pre-computing basenames and using Sets
 for intersection

Pre-computes basenames for matched elements and uses a single pass algorithm using Set tracking for multiple conditions matching, replacing redundant iterations of .filter and .some containing O(N*M) bottlenecks.
---
 cli/commands/diff.mjs        | 32 +++++++++++++++++++++++---------
 cli/validators/docs-diff.mjs | 30 ++++++++++++++++++++++--------
 2 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/cli/commands/diff.mjs b/cli/commands/diff.mjs
index 856eea1..8b3d33b 100644
--- a/cli/commands/diff.mjs
+++ b/cli/commands/diff.mjs
@@ -348,8 +348,9 @@ function diffTests(dir, config = {}) {
   // Glob-aware matching (documented entries are often patterns or basenames).
   const codeArr = [...codeTests];
 
-  // PERFORMANCE OPTIMIZATION: Pre-compile regular expressions to avoid O(N*M)
-  // instantiation bottlenecks inside the nested .filter and .some loops below.
+  // PERFORMANCE OPTIMIZATION: Pre-compile regular expressions and basenames to avoid O(N*M)
+  // instantiation and string processing bottlenecks. We use Sets to track matches in a
+  // single pass cross-comparison instead of multiple nested .filter and .some loops.
   const docMatchers = [...docTests].map(docEntry => {
     const entry = String(docEntry).trim();
     const hasSlash = entry.includes('/');
@@ -363,17 +364,30 @@ function diffTests(dir, config = {}) {
     };
   });
 
-  const matches = (matcher, codeRel) => {
-    const subject = matcher.hasSlash ? codeRel : basename(codeRel);
-    return matcher.rx.test(subject);
-  };
+  const codeItems = codeArr.map(c => ({
+    original: c,
+    basename: basename(c)
+  }));
+
+  const matchedDocs = new Set();
+  const matchedCode = new Set();
+
+  for (const m of docMatchers) {
+    for (const c of codeItems) {
+      const subject = m.hasSlash ? c.original : c.basename;
+      if (m.rx.test(subject)) {
+        matchedDocs.add(m.original);
+        matchedCode.add(c.original);
+      }
+    }
+  }
 
   return {
     title: 'Test Files',
     icon: '🧪',
-    onlyInDocs: docMatchers.filter(m => !codeArr.some(c => matches(m, c))).map(m => m.original),
-    onlyInCode: codeArr.filter(c => !docMatchers.some(m => matches(m, c))),
-    matched: docMatchers.filter(m => codeArr.some(c => matches(m, c))).map(m => m.original),
+    onlyInDocs: docMatchers.filter(m => !matchedDocs.has(m.original)).map(m => m.original),
+    onlyInCode: codeItems.filter(c => !matchedCode.has(c.original)).map(c => c.original),
+    matched: docMatchers.filter(m => matchedDocs.has(m.original)).map(m => m.original),
   };
 }
 
diff --git a/cli/validators/docs-diff.mjs b/cli/validators/docs-diff.mjs
index f9fef2b..a899c54 100644
--- a/cli/validators/docs-diff.mjs
+++ b/cli/validators/docs-diff.mjs
@@ -170,8 +170,9 @@ function diffTests(dir, config) {
   // Exact-string comparison produced the false "N documented but not found".
   const codeArr = [...codeTests];
 
-  // PERFORMANCE OPTIMIZATION: Pre-compile regular expressions to avoid O(N*M)
-  // instantiation bottlenecks inside the nested .filter and .some loops below.
+  // PERFORMANCE OPTIMIZATION: Pre-compile regular expressions and basenames to avoid O(N*M)
+  // instantiation and string processing bottlenecks. We use Sets to track matches in a
+  // single pass cross-comparison instead of multiple nested .filter and .some loops.
   const docMatchers = [...docTests].map(docEntry => {
     const entry = String(docEntry).trim();
     const hasSlash = entry.includes('/');
@@ -188,15 +189,28 @@ function diffTests(dir, config) {
     };
   });
 
-  const matches = (matcher, codeRel) => {
-    const subject = matcher.hasSlash ? codeRel : basename(codeRel);
-    return matcher.rx.test(subject);
-  };
+  const codeItems = codeArr.map(c => ({
+    original: c,
+    basename: basename(c)
+  }));
+
+  const matchedDocs = new Set();
+  const matchedCode = new Set();
+
+  for (const m of docMatchers) {
+    for (const c of codeItems) {
+      const subject = m.hasSlash ? c.original : c.basename;
+      if (m.rx.test(subject)) {
+        matchedDocs.add(m.original);
+        matchedCode.add(c.original);
+      }
+    }
+  }
 
   return {
     title: 'Test Files',
-    onlyInDocs: docMatchers.filter(m => !codeArr.some(c => matches(m, c))).map(m => m.original),
-    onlyInCode: codeArr.filter(c => !docMatchers.some(m => matches(m, c))),
+    onlyInDocs: docMatchers.filter(m => !matchedDocs.has(m.original)).map(m => m.original),
+    onlyInCode: codeItems.filter(c => !matchedCode.has(c.original)).map(c => c.original),
   };
 }