From f80bcb198117a8f6eb33e131de2bba8167b52a14 Mon Sep 17 00:00:00 2001
From: neverland <chenjiahan.jait@bytedance.com>
Date: Wed, 5 Aug 2026 10:40:35 +0800
Subject: [PATCH] perf(fmt): avoid relative path resolution under root

---
 packages/rstack/src/fmt/ignore.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/packages/rstack/src/fmt/ignore.ts b/packages/rstack/src/fmt/ignore.ts
index b27ce88..c313ce3 100644
--- a/packages/rstack/src/fmt/ignore.ts
+++ b/packages/rstack/src/fmt/ignore.ts
@@ -22,9 +22,12 @@ interface CreateIgnoreMatcherOptions {
 
 const createPatternMatcher = (rootPath: string, patterns: string): IgnoreMatcher => {
   const matcher = createIgnore({ allowRelativePaths: true }).add(patterns);
+  const rootPrefix = rootPath.endsWith(path.sep) ? rootPath : `${rootPath}${path.sep}`;
 
   return (filePath, isDirectory = false) => {
-    const relativePath = path.relative(rootPath, filePath);
+    const relativePath = filePath.startsWith(rootPrefix)
+      ? filePath.slice(rootPrefix.length)
+      : path.relative(rootPath, filePath);
     if (relativePath === '') {
       return false;
     }