From 67fc99e8e27961dad96b0808dcc48b5c91059ea8 Mon Sep 17 00:00:00 2001
From: Thavamani Murugan <thavamanimurugan@Thavamanis-MacBook-Air.local>
Date: Sun, 26 Apr 2026 09:20:14 +0530
Subject: [PATCH] fix(glob): throw descriptive error for unbalanced braces in
 glob patterns

Fixes: https://github.com/microsoft/playwright/issues/40422
---
 packages/isomorphic/urlMatch.ts | 6 ++++++
 tests/page/interception.spec.ts | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/packages/isomorphic/urlMatch.ts b/packages/isomorphic/urlMatch.ts
index cdd7f0aab0a61..1b48e42ca34e4 100644
--- a/packages/isomorphic/urlMatch.ts
+++ b/packages/isomorphic/urlMatch.ts
@@ -56,10 +56,14 @@ export function globToRegexPattern(glob: string): string {
 
     switch (c) {
       case '{':
+        if (inGroup)
+          throw new Error(`Invalid glob pattern "${glob}": nested '{' is not supported`);
         inGroup = true;
         tokens.push('(');
         break;
       case '}':
+        if (!inGroup)
+          throw new Error(`Invalid glob pattern "${glob}": unmatched '}'`);
         inGroup = false;
         tokens.push(')');
         break;
@@ -74,6 +78,8 @@ export function globToRegexPattern(glob: string): string {
         tokens.push(escapedChars.has(c) ? '\\' + c : c);
     }
   }
+  if (inGroup)
+    throw new Error(`Invalid glob pattern "${glob}": unmatched '{'`);
   tokens.push('$');
   return tokens.join('');
 }
diff --git a/tests/page/interception.spec.ts b/tests/page/interception.spec.ts
index e96e126f00b97..0db1e4c510948 100644
--- a/tests/page/interception.spec.ts
+++ b/tests/page/interception.spec.ts
@@ -164,6 +164,14 @@ it('should work with glob', async () => {
     expect(urlMatches(undefined, `${prefix}:blank`, `${prefix}:*`)).toBeTruthy();
     expect(urlMatches(undefined, `not${prefix}:blank`, `${prefix}:*`)).toBeFalsy();
   }
+
+  // Unbalanced braces must throw early with a descriptive error.
+  expect(() => globToRegexPattern('{foo')).toThrow(`Invalid glob pattern "{foo": unmatched '{'`);
+  expect(() => globToRegexPattern('}foo')).toThrow(`Invalid glob pattern "}foo": unmatched '}'`);
+  expect(() => globToRegexPattern('**/*.png?{')).toThrow(`Invalid glob pattern "**/*.png?{": unmatched '{'`);
+  expect(() => globToRegexPattern('https://example.com/{a')).toThrow(`Invalid glob pattern "https://example.com/{a": unmatched '{'`);
+  expect(() => globToRegexPattern('{a,b')).toThrow(`Invalid glob pattern "{a,b": unmatched '{'`);
+  expect(() => globToRegexPattern('{a,{b}}')).toThrow(`Invalid glob pattern "{a,{b}}": nested '{' is not supported`);
 });
 
 it('should intercept by glob', async function({ page, server, isAndroid }) {