From d8d2903670c704494aabef1a9fbd5f54b1c90971 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 26 Aug 2026 14:04:26 +0000
Subject: [PATCH] perf: optimize referencedTitles text matching in workspace

Replaces regex matchAll with manual indexOf scanning for parsing references, significantly improving text scanning performance. Uses sticky regex fallback for bare identifiers.

Co-authored-by: Horizontal42 <75383519+Horizontal42@users.noreply.github.com>
---
 src/workspace.ts | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/workspace.ts b/src/workspace.ts
index bc768b8..3669def 100644
--- a/src/workspace.ts
+++ b/src/workspace.ts
@@ -19,6 +19,7 @@ interface SheetExports {
 }
 
 const XREF_SCAN_RE = /@(?:\[([^\]]+)\]|([\p{L}_][\p{L}\d_]*))\./gu;
+const XREF_BARE_RE_STICKY = /@([\p{L}_][\p{L}\d_]*)\./guy;
 
 function escapeRegExp(s: string): string {
   return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
@@ -104,7 +105,28 @@ export class Workspace {
       if (cached && cached.text === text) return cached.refs;
     }
     const out: string[] = [];
-    for (const m of text.matchAll(XREF_SCAN_RE)) out.push((m[1] ?? m[2]).trim());
+    let i = 0;
+    while ((i = text.indexOf("@", i)) !== -1) {
+      if (i + 1 >= text.length) break;
+
+      if (text[i + 1] === "[") {
+        const endBracket = text.indexOf("]", i + 2);
+        if (endBracket !== -1 && endBracket + 1 < text.length && text[endBracket + 1] === ".") {
+          out.push(text.substring(i + 2, endBracket).trim());
+          i = endBracket + 2;
+          continue;
+        }
+      } else {
+        XREF_BARE_RE_STICKY.lastIndex = i;
+        const m = XREF_BARE_RE_STICKY.exec(text);
+        if (m !== null) {
+          out.push(m[1]); // no trim needed for bare identifier regex match
+          i = XREF_BARE_RE_STICKY.lastIndex;
+          continue;
+        }
+      }
+      i++;
+    }
     if (id) {
       this.parsedRefsCache.set(id, { text, refs: out });
     }