gh-137586: Fix MacOS plist fallback, builtins.open shadow, add Brave

Return 'com.apple.Safari' instead of None when the LaunchServices plist is
absent (fresh installs never write it). None caused the non-http branch to
fall back to bare '/usr/bin/open <url>', bypassing -b and triggering the OS
file handler. Addresses gpshead's CHANGES_REQUESTED.

Fix infinite recursion: webbrowser's module-level open() shadowed
builtins.open, so open(plist, 'rb') called webbrowser.open() recursively
on every non-http/https URL. Use builtins.open() explicitly.

Narrow 'except Exception' to '(OSError, KeyError, ValueError)'. Addresses
hugovk's review comment.

Add 'brave browser': 'com.brave.Browser' to _BUNDLE_IDS and register it
so webbrowser.get('brave') works and Brave uses precise -b dispatch instead
of the name-based -a fallback.

Tested locally against Safari, Chrome, Firefox, Opera, Edge, and Brave
with https, http, and file:// URLs. 29/29 checks pass.

Author: secengjeff

Lib/test/test_webbrowser.py

@@ -351,30 +351,16 @@ def test_default_non_http_uses_bundle_id(self):
         file_url = 'file:///tmp/test.html'
         browser = webbrowser.MacOS('default')
         with mock.patch('webbrowser._macos_default_browser_bundle_id',
-                        return_value='com.apple.Safari'), \
+                        return_value='com.google.Chrome'), \
              mock.patch('subprocess.run') as mock_run:
             mock_run.return_value = mock.Mock(returncode=0)
             result = browser.open(file_url)
         mock_run.assert_called_once_with(
-            ['/usr/bin/open', '-b', 'com.apple.Safari', file_url],
+            ['/usr/bin/open', '-b', 'com.google.Chrome', file_url],
             stderr=subprocess.DEVNULL,
         )
         self.assertTrue(result)
 
-    def test_default_non_http_fallback_when_no_bundle_id(self):
-        # If the bundle ID lookup fails, fall back to /usr/bin/open without -b.
-        file_url = 'file:///tmp/test.html'
-        browser = webbrowser.MacOS('default')
-        with mock.patch('webbrowser._macos_default_browser_bundle_id',
-                        return_value=None), \
-             mock.patch('subprocess.run') as mock_run:
-            mock_run.return_value = mock.Mock(returncode=0)
-            browser.open(file_url)
-        mock_run.assert_called_once_with(
-            ['/usr/bin/open', file_url],
-            stderr=subprocess.DEVNULL,
-        )
-
     def test_named_known_browser_uses_bundle_id(self):
         # Named browsers with a known bundle ID use /usr/bin/open -b.
         browser = webbrowser.MacOS('safari')

Lib/webbrowser.py

@@ -498,6 +498,7 @@ def register_standard_browsers():
         register("safari", None, MacOS('safari'))
         register("opera", None, MacOS('opera'))
         register("microsoft-edge", None, MacOS('microsoft edge'))
+        register("brave", None, MacOS('brave browser'))
         # macOS can use below Unix support (but we prefer using the macOS
         # specific stuff)
 
@@ -620,24 +621,27 @@ def _macos_default_browser_bundle_id():
         """Return the bundle ID of the default web browser.
 
         Reads the LaunchServices preferences file that macOS maintains
-        when the user sets a default browser. Returns None if the file
-        is absent or no https handler is recorded.
+        when the user sets a default browser. Returns 'com.apple.Safari'
+        if the file is absent or no https handler is recorded, because on
+        a fresh macOS installation Safari is the default browser and the
+        LaunchServices plist is not written until the user explicitly
+        changes their default browser.
         """
-        import plistlib, os
+        import builtins, plistlib, os
         plist = os.path.expanduser(
             '~/Library/Preferences/com.apple.LaunchServices/'
             'com.apple.launchservices.secure.plist'
         )
         try:
-            with open(plist, 'rb') as f:
+            with builtins.open(plist, 'rb') as f:
                 data = plistlib.load(f)
             for handler in data.get('LSHandlers', []):
                 if handler.get('LSHandlerURLScheme') == 'https':
                     return (handler.get('LSHandlerRoleAll')
                             or handler.get('LSHandlerRoleViewer'))
-        except Exception:
+        except (OSError, KeyError, ValueError):
             pass
-        return None
+        return 'com.apple.Safari'
 
     class MacOS(BaseBrowser):
         """Launcher class for macOS browsers, using /usr/bin/open.
@@ -662,6 +666,7 @@ class MacOS(BaseBrowser):
             'chromium':       'org.chromium.Chromium',
             'opera':          'com.operasoftware.Opera',
             'microsoft edge': 'com.microsoft.edgemac',
+            'brave browser':  'com.brave.Browser',
         }
 
         def open(self, url, new=0, autoraise=True):
@@ -673,10 +678,7 @@ def open(self, url, new=0, autoraise=True):
                     cmd = ['/usr/bin/open', url]
                 else:
                     bundle_id = _macos_default_browser_bundle_id()
-                    if bundle_id:
-                        cmd = ['/usr/bin/open', '-b', bundle_id, url]
-                    else:
-                        cmd = ['/usr/bin/open', url]
+                    cmd = ['/usr/bin/open', '-b', bundle_id, url]
             else:
                 bundle_id = self._BUNDLE_IDS.get(self.name.lower())
                 if bundle_id: