From f260cb51fa99ac27cf705af5fb3835750783a64d Mon Sep 17 00:00:00 2001
From: chatman-media <chatman-media@users.noreply.github.com>
Date: Fri, 19 Jun 2026 22:57:56 +0700
Subject: [PATCH] fix: forward `windows` option to basename in matchBase

`picomatch.matchBase` stopped honoring the `windows` option after the
switch from Node's `path.basename` to `utils.basename` (2f25761,
"Remove automatic windows detection"). The `posix` argument that
`picomatch.test` still passes was dropped from the signature, and
`utils.basename(input)` was called without the `{ windows }` flag, so
backslash-separated paths were never split into segments.

As a result `isMatch('a\\b\\c\\foo.md', '*.md', { matchBase: true,
windows: true })` returned `false` even though `utils.basename` already
supports `{ windows: true }` (and is tested for it).

Restore the `posix` parameter (defaulting to `options.windows`, as in
`picomatch.test`) and pass it through to `utils.basename`.
---
 lib/picomatch.js |  4 ++--
 test/options.js  | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/lib/picomatch.js b/lib/picomatch.js
index fbb8b1ca..448d354b 100644
--- a/lib/picomatch.js
+++ b/lib/picomatch.js
@@ -157,9 +157,9 @@ picomatch.test = (input, regex, options, { glob, posix } = {}) => {
  * @api public
  */
 
-picomatch.matchBase = (input, glob, options) => {
+picomatch.matchBase = (input, glob, options, posix = options && options.windows) => {
   const regex = glob instanceof RegExp ? glob : picomatch.makeRe(glob, options);
-  return regex.test(utils.basename(input));
+  return regex.test(utils.basename(input, { windows: posix }));
 };
 
 /**
diff --git a/test/options.js b/test/options.js
index 8993d181..5d0f98af 100644
--- a/test/options.js
+++ b/test/options.js
@@ -2,7 +2,7 @@
 
 const assert = require('assert');
 const match = require('./support/match');
-const { isMatch } = require('..');
+const { isMatch, matchBase } = require('..');
 
 describe('options', () => {
   describe('options.matchBase', () => {
@@ -15,6 +15,19 @@ describe('options', () => {
       assert.deepStrictEqual(match(['x/y/acb', 'acb/', 'acb/d/e', 'x/y/acb/d'], 'a?b', { matchBase: true, windows: true }), ['x/y/acb', 'acb/']);
     });
 
+    it('should match the basename of backslash-separated paths when `options.windows` is true', () => {
+      assert(isMatch('foo\\bar.js', '*.js', { matchBase: true, windows: true }));
+      assert(isMatch('a\\b\\c\\d.md', '*.md', { matchBase: true, windows: true }));
+      assert(isMatch('a\\b\\c\\foo.md', '*.md', { matchBase: true, windows: true }));
+      assert(isMatch('x\\y\\acb', 'a?b', { matchBase: true, windows: true }));
+      assert(!isMatch('a\\b\\c\\d.md', '*.js', { matchBase: true, windows: true }));
+    });
+
+    it('should pass the `windows` option through `matchBase`', () => {
+      assert(matchBase('foo\\bar.js', '*.js', { windows: true }));
+      assert(matchBase('a\\b\\c\\d.md', '*.md', { windows: true }));
+    });
+
     it('should work with negation patterns', () => {
       assert(isMatch('./x/y.js', '*.js', { matchBase: true, windows: true }));
       assert(!isMatch('./x/y.js', '!*.js', { matchBase: true, windows: true }));