Ignore annotation-only assignment statements in redundant-assignment …

…check
pyta-uoft · Jan 16, 2025 · 726b7ae · 726b7ae
1 parent 31b9659
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Showing 3 changed files with 21 additions and 2 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -13,6 +13,8 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### 🐛 Bug fixes
 
+- Ignore annotation-only assignment statements in `redundant-assignment` check
+
 ### 🔧 Internal changes
 
 ## [2.9.1] - 2024-12-09

diff --git a/python_ta/checkers/redundant_assignment_checker.py b/python_ta/checkers/redundant_assignment_checker.py
@@ -76,7 +76,7 @@ def visit_augassign(self, node: nodes.AugAssign) -> None:
     @only_required_for_messages("redundant-assignment")
     def visit_annassign(self, node: nodes.AnnAssign) -> None:
         """Visit the annotated assign node"""
-        if node in self._redundant_assignment:
+        if node.value is not None and node in self._redundant_assignment:
             self.add_message("redundant-assignment", node=node, args=node.target.name)
 
     def visit_module(self, node: nodes.Module) -> None:
@@ -151,7 +151,9 @@ def _transfer(self, block: CFGBlock, out_facts: set[str]) -> set[str]:
                     parent = (
                         node.parent.parent if isinstance(node.parent, nodes.Tuple) else node.parent
                     )
-                    if node.name in gen.difference(kill):
+                    if isinstance(parent, nodes.AnnAssign) and parent.value is None:
+                        continue
+                    elif node.name in gen.difference(kill):
                         # add redundant assignment
                         if parent not in self._redundant_assignment:
                             self._redundant_assignment[parent] = []

diff --git a/tests/test_custom_checkers/test_redundant_assignment_checker.py b/tests/test_custom_checkers/test_redundant_assignment_checker.py
@@ -336,6 +336,21 @@ def test_multiple_target_assign_one_variable_redundant(self):
         ):
             self.checker.visit_assign(assign_node)
 
+    def test_ignore_annotation_only_annassigns(self):
+        src = """
+        x: int
+        x = 10
+        """
+        mod = astroid.parse(src)
+        mod.accept(CFGVisitor())
+
+        self.checker.visit_module(mod)
+        with self.assertNoMessages():
+            for node in mod.nodes_of_class(nodes.Assign):
+                self.checker.visit_assign(node)
+            for node in mod.nodes_of_class(nodes.AnnAssign):
+                self.checker.visit_augassign(node)
+
 
 class TestRedundantAssignmentCheckerZ3Option(pylint.testutils.CheckerTestCase):
     CHECKER_CLASS = RedundantAssignmentChecker