Fixes #4040, #5378 - signal has no connect member

.gitignore

@@ -15,3 +15,4 @@ astroid.egg-info/
 .pytest_cache/
 .mypy_cache/
 venv
+doc/_build/

ChangeLog

@@ -6,6 +6,10 @@ What's New in astroid 2.12.0?
 =============================
 Release date: TBA
 
+* Fix signal has no ``connect`` member for PySide2 5.15.2+ and PySide6
+
+  Closes #4040, #5378
+
 * ``astroid`` now requires Python 3.7.2 to run.
 
 * Avoid setting a Call as a base for classes created using ``six.with_metaclass()``.

astroid/brain/brain_qt.py

@@ -10,11 +10,17 @@
 from astroid.manager import AstroidManager
 
 
-def _looks_like_signal(node, signal_name="pyqtSignal"):
-    if "__class__" in node.instance_attrs:
+def _looks_like_signal(
+    node: nodes.FunctionDef, signal_name: str = "pyqtSignal"
+) -> bool:  # pragma: no cover
+    """Detect a Signal node."""
+    klasses = node.instance_attrs.get("__class__", [])
+    # On PySide2 or PySide6 (since  Qt 5.15.2) the Signal class changed locations
+    if node.qname().partition(".")[0] in {"PySide2", "PySide6"}:
+        return any(cls.qname() == "Signal" for cls in klasses)
+    if klasses:
         try:
-            cls = node.instance_attrs["__class__"][0]
-            return cls.name == signal_name
+            return klasses[0].name == signal_name
         except AttributeError:
             # return False if the cls does not have a name attribute
             pass
@@ -79,4 +85,4 @@ def emit(self, signal): pass
     nodes.ClassDef,
     transform_pyside_signal,
     lambda node: node.qname() in {"PySide.QtCore.Signal", "PySide2.QtCore.Signal"},
-)
+)  # pragma: no cover

script/.contributors_aliases.json

@@ -169,5 +169,9 @@
   "[email protected]": {
     "mails": ["[email protected]", "[email protected]"],
     "name": "Ville Skyttä"
+  },
+  "[email protected]": {
+    "mails": ["[email protected]"],
+    "name": "Adam Hendry"
   }
 }

tests/unittest_brain_qt.py

@@ -14,9 +14,14 @@
 HAS_PYQT6 = find_spec("PyQt6")
 
 
-@pytest.mark.skipif(HAS_PYQT6 is None, reason="This test requires the PyQt6 library.")
+@pytest.mark.skipif(
+    HAS_PYQT6 is None,
+    reason="These tests require the PyQt6 library.",
+)
 class TestBrainQt:
-    AstroidManager.brain["extension_package_whitelist"] = {"PyQt6"}
+    AstroidManager.brain["extension_package_whitelist"] = {
+        "PyQt6",
+    }
 
     @staticmethod
     def test_value_of_lambda_instance_attrs_is_list():