Qt 6.4: Add --webEngineArgs

See #7314

qutebrowser/config/qtargs.py

@@ -75,10 +75,15 @@ def qt_args(namespace: argparse.Namespace) -> List[str]:
         log.init.debug("QtWebEngine requested, but unavailable...")
         return argv
 
+    versions = version.qtwebengine_versions(avoid_init=True)
+    if versions.webengine >= utils.VersionNumber(6, 4):
+        # https://codereview.qt-project.org/c/qt/qtwebengine/+/376704
+        argv.insert(1, "--webEngineArgs")
+
     special_prefixes = (_ENABLE_FEATURES, _DISABLE_FEATURES, _BLINK_SETTINGS)
     special_flags = [flag for flag in argv if flag.startswith(special_prefixes)]
     argv = [flag for flag in argv if not flag.startswith(special_prefixes)]
-    argv += list(_qtwebengine_args(namespace, special_flags))
+    argv += list(_qtwebengine_args(versions, namespace, special_flags))
 
     return argv
 
@@ -241,12 +246,11 @@ def _get_lang_override(
 
 
 def _qtwebengine_args(
+        versions: version.WebEngineVersions,
         namespace: argparse.Namespace,
         special_flags: Sequence[str],
 ) -> Iterator[str]:
     """Get the QtWebEngine arguments to use based on the config."""
-    versions = version.qtwebengine_versions(avoid_init=True)
-
     # https://codereview.qt-project.org/c/qt/qtwebengine/+/256786
     # https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/265753
     if 'stack' in namespace.debug_flags:

tests/unit/config/test_qtargs.py

@@ -41,11 +41,17 @@ def parser(mocker):
 @pytest.fixture
 def version_patcher(monkeypatch):
     """Get a patching function to patch the QtWebEngine version."""
-    def run(ver):
+    def run(ver) -> bool:
+        """Run patching.
+
+        Return:
+            True if we know the associated Chromium version, False otherwise
+        """
         versions = version.WebEngineVersions.from_pyqt(ver)
         monkeypatch.setattr(qtargs.objects, 'backend', usertypes.Backend.QtWebEngine)
         monkeypatch.setattr(version, 'qtwebengine_versions',
                             lambda avoid_init: versions)
+        return versions.chromium_major is not None
 
     return run
 
@@ -482,6 +488,28 @@ class TestWebEngineArgs:
         args = qtargs.qt_args(parsed)
         assert '--lang=de' in args
 
+    @pytest.mark.parametrize("version, expected", [
+        ('5.15.2', False),
+        ('5.15.9', False),
+        ('6.2.4', False),
+        ('6.3.1', False),
+        ('6.4.0', True),
+        ('6.5.0', True),
+    ])
+    def test_webengine_args(self, version_patcher, parser, version, expected):
+        known_chromium = version_patcher(version)
+        if not known_chromium:
+            pytest.skip("Don't know associated Chromium version")
+
+        parsed = parser.parse_args([])
+        args = qtargs.qt_args(parsed)
+
+        flag = "--webEngineArgs"
+        if expected:
+            assert args[1] == flag
+        else:
+            assert flag not in args
+
 
 class TestEnvVars: