Fix instance_attrs building error in Qt brain (#1505)

Co-authored-by: Daniël van Noord <13665637+DanielNoord@users.noreply.github.com>

.github/workflows/release-tests.yml

@@ -31,3 +31,31 @@ jobs:
           . venv2\scripts\activate
           echo "import distutils.util  # pylint: disable=unused-import" > test.py
           pylint test.py
+
+  additional-dependencies-linux-tests:
+    name: Regression tests w/ additional dependencies (Linux)
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - name: Check out code from GitHub
+        uses: actions/checkout@v3.0.0
+      - name: Set up Python
+        id: python
+        uses: actions/setup-python@v3.1.0
+        with:
+          python-version: ${{ env.DEFAULT_PYTHON }}
+      - name: Install Qt
+        run: |
+          sudo apt-get install build-essential libgl1-mesa-dev
+      - name: Create Python virtual environment
+        run: |
+          python -m venv venv
+          . venv/bin/activate
+          python -m pip install -U pip setuptools wheel
+          pip install -U -r requirements_test.txt -r requirements_test_brain.txt
+          pip install -e .
+      - name: Run brain_qt tests
+        # Regression test added in https://github.com/PyCQA/astroid/pull/1505
+        run: |
+          . venv/bin/activate
+          pytest tests/unittest_brain_qt.py

ChangeLog

@@ -12,6 +12,9 @@ What's New in astroid 2.11.3?
 =============================
 Release date: TBA
 
+* Fixed an error in the Qt brain when building ``instance_attrs``.
+
+  Closes PyCQA/pylint#6221
 
 
 What's New in astroid 2.11.2?

astroid/brain/brain_qt.py

@@ -21,7 +21,7 @@ def _looks_like_signal(node, signal_name="pyqtSignal"):
     return False
 
 
-def transform_pyqt_signal(node):
+def transform_pyqt_signal(node: nodes.FunctionDef) -> None:
     module = parse(
         """
     class pyqtSignal(object):
@@ -33,13 +33,13 @@ def emit(self, *args):
             pass
     """
     )
-    signal_cls = module["pyqtSignal"]
-    node.instance_attrs["emit"] = signal_cls["emit"]
-    node.instance_attrs["disconnect"] = signal_cls["disconnect"]
-    node.instance_attrs["connect"] = signal_cls["connect"]
+    signal_cls: nodes.ClassDef = module["pyqtSignal"]
+    node.instance_attrs["emit"] = [signal_cls["emit"]]
+    node.instance_attrs["disconnect"] = [signal_cls["disconnect"]]
+    node.instance_attrs["connect"] = [signal_cls["connect"]]
 
 
-def transform_pyside_signal(node):
+def transform_pyside_signal(node: nodes.FunctionDef) -> None:
     module = parse(
         """
     class NotPySideSignal(object):
@@ -51,10 +51,10 @@ def emit(self, *args):
             pass
     """
     )
-    signal_cls = module["NotPySideSignal"]
-    node.instance_attrs["connect"] = signal_cls["connect"]
-    node.instance_attrs["disconnect"] = signal_cls["disconnect"]
-    node.instance_attrs["emit"] = signal_cls["emit"]
+    signal_cls: nodes.ClassDef = module["NotPySideSignal"]
+    node.instance_attrs["connect"] = [signal_cls["connect"]]
+    node.instance_attrs["disconnect"] = [signal_cls["disconnect"]]
+    node.instance_attrs["emit"] = [signal_cls["emit"]]
 
 
 def pyqt4_qtcore_transform():

astroid/nodes/scoped_nodes/mixin.py

@@ -108,11 +108,10 @@ def add_local_node(self, child_node, name=None):
             self._append_node(child_node)
         self.set_local(name or child_node.name, child_node)
 
-    def __getitem__(self, item):
+    def __getitem__(self, item: str) -> "nodes.NodeNG":
         """The first node the defines the given local.
 
         :param item: The name of the locally defined object.
-        :type item: str
 
         :raises KeyError: If the name is not defined.
         """

requirements_test_brain.txt

@@ -3,6 +3,7 @@ types-attrs
 nose
 numpy>=1.17.0
 python-dateutil
+PyQt6
 types-python-dateutil
 six
 types-six

tests/unittest_brain_qt.py

@@ -0,0 +1,38 @@
+# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
+# For details: https://github.com/PyCQA/astroid/blob/main/LICENSE
+# Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt
+
+from importlib.util import find_spec
+
+import pytest
+
+from astroid import Uninferable, extract_node
+from astroid.bases import UnboundMethod
+from astroid.manager import AstroidManager
+from astroid.nodes import FunctionDef
+
+HAS_PYQT6 = find_spec("PyQt6")
+
+
+@pytest.mark.skipif(HAS_PYQT6 is None, reason="This test requires the PyQt6 library.")
+class TestBrainQt:
+    @staticmethod
+    def test_value_of_lambda_instance_attrs_is_list():
+        """Regression test for https://github.com/PyCQA/pylint/issues/6221
+
+        A crash occurred in pylint when a nodes.FunctionDef was iterated directly,
+        giving items like "self" instead of iterating a one-element list containing
+        the wanted nodes.FunctionDef.
+        """
+        src = """
+        from PyQt6 import QtPrintSupport as printsupport
+        printsupport.QPrintPreviewDialog.paintRequested  #@
+        """
+        AstroidManager.brain["extension_package_whitelist"] = {"PyQt6.QtPrintSupport"}
+        node = extract_node(src)
+        attribute_node = node.inferred()[0]
+        if attribute_node is Uninferable:
+            pytest.skip("PyQt6 C bindings may not be installed?")
+        assert isinstance(attribute_node, UnboundMethod)
+        # scoped_nodes.Lambda.instance_attrs is typed as Dict[str, List[NodeNG]]
+        assert isinstance(attribute_node.instance_attrs["connect"][0], FunctionDef)