Handle functions defined under type-checking

Author: zenlyj

pylint/checkers/variables.py

@@ -723,7 +723,7 @@ def _uncertain_nodes_if_tests(
                 name = other_node.name
             elif isinstance(other_node, (nodes.Import, nodes.ImportFrom)):
                 name = node.name
-            elif isinstance(other_node, nodes.ClassDef):
+            elif isinstance(other_node, (nodes.FunctionDef, nodes.ClassDef)):
                 name = other_node.name
             else:
                 continue
@@ -1268,6 +1268,7 @@ def __init__(self, linter: PyLinter) -> None:
         self._reported_type_checking_usage_scopes: dict[
             str, list[nodes.LocalsDictNodeNG]
         ] = {}
+        self._nonlocal_names: set[str] = set()
         self._postponed_evaluation_enabled = False
 
     @utils.only_required_for_messages(
@@ -1434,6 +1435,9 @@ def leave_setcomp(self, _: nodes.SetComp) -> None:
     def visit_functiondef(self, node: nodes.FunctionDef) -> None:
         """Visit function: update consumption analysis variable and check locals."""
         self._to_consume.append(NamesConsumer(node, "function"))
+        self._nonlocal_names.update(
+            _flattened_scope_names(node.nodes_of_class(nodes.Nonlocal))
+        )
         if not (
             self.linter.is_message_enabled("redefined-outer-name")
             or self.linter.is_message_enabled("redefined-builtin")
@@ -1483,6 +1487,7 @@ def visit_functiondef(self, node: nodes.FunctionDef) -> None:
     def leave_functiondef(self, node: nodes.FunctionDef) -> None:
         """Leave function: check function's locals are consumed."""
         self._check_metaclasses(node)
+        self._nonlocal_names = set()
 
         if node.type_comment_returns:
             self._store_type_annotation_node(node.type_comment_returns)
@@ -1874,12 +1879,18 @@ def _check_consumer(
 
                 # Skip postponed evaluation of annotations
                 # and unevaluated annotations inside a function body
-                if not (
-                    self._postponed_evaluation_enabled
-                    and isinstance(stmt, (nodes.AnnAssign, nodes.FunctionDef))
-                ) and not (
-                    isinstance(stmt, nodes.AnnAssign)
-                    and utils.get_node_first_ancestor_of_type(stmt, nodes.FunctionDef)
+                if (
+                    not (
+                        self._postponed_evaluation_enabled
+                        and isinstance(stmt, (nodes.AnnAssign, nodes.FunctionDef))
+                    )
+                    and not (
+                        isinstance(stmt, nodes.AnnAssign)
+                        and utils.get_node_first_ancestor_of_type(
+                            stmt, nodes.FunctionDef
+                        )
+                    )
+                    and not node.name in self._nonlocal_names
                 ):
                     self.add_message(
                         "used-before-assignment",
@@ -1964,6 +1975,8 @@ def _report_unfound_name_definition(
             and node.scope() in self._reported_type_checking_usage_scopes[node.name]
         ):
             return False
+        if node.name in self._nonlocal_names:
+            return False
 
         confidence = HIGH
         if node.name in current_consumer.names_under_always_false_test:

tests/functional/u/used/used_before_assignment.py

@@ -256,7 +256,7 @@ def outer_():
     def inner_try():
         try:
             nonlocal a
-            print(a)  # [used-before-assignment] FALSE POSITIVE
+            print(a)
             a = 2
             print(a)
         except:
@@ -267,7 +267,7 @@ def inner_while():
         while i < 2:
             i += 1
             nonlocal a
-            print(a)  # [used-before-assignment] FALSE POSITIVE
+            print(a)
             a = 2
             print(a)
 

tests/functional/u/used/used_before_assignment.txt

@@ -15,5 +15,3 @@ used-before-assignment:184:10:184:18::Using variable 'ALL_DONE' before assignmen
 used-before-assignment:195:6:195:24::Using variable 'NOT_ALWAYS_DEFINED' before assignment:INFERENCE
 used-before-assignment:231:10:231:11::Using variable 'x' before assignment:CONTROL_FLOW
 possibly-used-before-assignment:245:10:245:15:__:Possibly using variable 'fail1' before assignment:CONTROL_FLOW
-used-before-assignment:259:18:259:19:outer_.inner_try:Using variable 'a' before assignment:HIGH
-used-before-assignment:270:18:270:19:outer_.inner_while:Using variable 'a' before assignment:HIGH

tests/functional/u/used/used_before_assignment_typing.py

@@ -173,7 +173,7 @@ def defined_in_elif_branch(self) -> calendar.Calendar:  # [possibly-used-before-
 
     def defined_in_else_branch(self) -> urlopen:
         print(zoneinfo)  # [used-before-assignment]
-        print(pprint())
+        print(pprint())  # [used-before-assignment]
         print(collections())  # [used-before-assignment]
         return urlopen
 

tests/functional/u/used/used_before_assignment_typing.txt

@@ -6,6 +6,7 @@ used-before-assignment:153:20:153:28:VariableAnnotationsGuardedByTypeChecking:Us
 possibly-used-before-assignment:170:40:170:48:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'calendar' before assignment:INFERENCE
 possibly-used-before-assignment:171:14:171:20:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'bisect' before assignment:INFERENCE
 used-before-assignment:175:14:175:22:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'zoneinfo' before assignment:INFERENCE
+used-before-assignment:176:14:176:20:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'pprint' before assignment:INFERENCE
 used-before-assignment:177:14:177:25:TypeCheckingMultiBranch.defined_in_else_branch:Using variable 'collections' before assignment:INFERENCE
 possibly-used-before-assignment:180:43:180:48:TypeCheckingMultiBranch.defined_in_nested_if_else:Possibly using variable 'heapq' before assignment:INFERENCE
 used-before-assignment:184:39:184:44:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'array' before assignment:INFERENCE