Handle deferred evaluation of annotations in Python 3.14

doc/whatsnew/fragments/10149.feature

@@ -0,0 +1,3 @@
+Handle deferred evaluation of annotations in Python 3.14.
+
+Closes #10149

pylint/checkers/typecheck.py

@@ -975,8 +975,15 @@ class TypeChecker(BaseChecker):
     def open(self) -> None:
         py_version = self.linter.config.py_version
         self._py310_plus = py_version >= (3, 10)
+        self._py314_plus = py_version >= (3, 14)
+        self._postponed_evaluation_enabled = False
         self._mixin_class_rgx = self.linter.config.mixin_class_rgx
 
+    def visit_module(self, node: nodes.Module) -> None:
+        self._postponed_evaluation_enabled = (
+            self._py314_plus or is_postponed_evaluation_enabled(node)
+        )
+
     @cached_property
     def _compiled_generated_members(self) -> tuple[Pattern[str], ...]:
         # do this lazily since config not fully initialized in __init__
@@ -1065,7 +1072,7 @@ def visit_attribute(
         ):
             return
 
-        if is_postponed_evaluation_enabled(node) and is_node_in_type_annotation_context(
+        if self._postponed_evaluation_enabled and is_node_in_type_annotation_context(
             node
         ):
             return
@@ -1949,9 +1956,10 @@ def _detect_unsupported_alternative_union_syntax(self, node: nodes.BinOp) -> Non
         if self._py310_plus:  # 310+ supports the new syntax
             return
 
-        if isinstance(
-            node.parent, TYPE_ANNOTATION_NODES_TYPES
-        ) and not is_postponed_evaluation_enabled(node):
+        if (
+            isinstance(node.parent, TYPE_ANNOTATION_NODES_TYPES)
+            and not self._postponed_evaluation_enabled
+        ):
             # Use in type annotations only allowed if
             # postponed evaluation is enabled.
             self._check_unsupported_alternative_union_syntax(node)
@@ -1973,7 +1981,7 @@ def _detect_unsupported_alternative_union_syntax(self, node: nodes.BinOp) -> Non
             # Make sure to filter context if postponed evaluation is enabled
             # and parent is allowed node type.
             allowed_nested_syntax = False
-            if is_postponed_evaluation_enabled(node):
+            if self._postponed_evaluation_enabled:
                 parent_node = node.parent
                 while True:
                     if isinstance(parent_node, TYPE_ANNOTATION_NODES_TYPES):

pylint/checkers/variables.py

@@ -1312,6 +1312,10 @@ def __init__(self, linter: PyLinter) -> None:
         ] = {}
         self._postponed_evaluation_enabled = False
 
+    def open(self) -> None:
+        py_version = self.linter.config.py_version
+        self._py314_plus = py_version >= (3, 14)
+
     @utils.only_required_for_messages(
         "unbalanced-dict-unpacking",
     )
@@ -1375,7 +1379,9 @@ def visit_module(self, node: nodes.Module) -> None:
         checks globals doesn't overrides builtins.
         """
         self._to_consume = [NamesConsumer(node, "module")]
-        self._postponed_evaluation_enabled = is_postponed_evaluation_enabled(node)
+        self._postponed_evaluation_enabled = (
+            self._py314_plus or is_postponed_evaluation_enabled(node)
+        )
 
         for name, stmts in node.locals.items():
             if utils.is_builtin(name):
@@ -2501,8 +2507,8 @@ def _is_only_type_assignment(
             parent = parent_scope.parent
         return True
 
-    @staticmethod
     def _is_first_level_self_reference(
+        self,
         node: nodes.Name,
         defstmt: nodes.ClassDef,
         found_nodes: list[nodes.NodeNG],
@@ -2514,7 +2520,7 @@ def _is_first_level_self_reference(
             # Check if used as type annotation
             # Break if postponed evaluation is enabled
             if utils.is_node_in_type_annotation_context(node):
-                if not utils.is_postponed_evaluation_enabled(node):
+                if not self._postponed_evaluation_enabled:
                     return (VariableVisitConsumerAction.CONTINUE, None)
                 return (VariableVisitConsumerAction.RETURN, None)
             # Check if used as default value by calling the class

pylint/extensions/typing.py

@@ -186,6 +186,8 @@ def open(self) -> None:
         self._py39_plus = py_version >= (3, 9)
         self._py310_plus = py_version >= (3, 10)
         self._py313_plus = py_version >= (3, 13)
+        self._py314_plus = py_version >= (3, 14)
+        self._postponed_evaluation_enabled = False
 
         self._should_check_typing_alias = self._py39_plus or (
             self._py37_plus and self.linter.config.runtime_typing is False
@@ -197,6 +199,11 @@ def open(self) -> None:
         self._should_check_noreturn = py_version < (3, 7, 2)
         self._should_check_callable = py_version < (3, 9, 2)
 
+    def visit_module(self, node: nodes.Module) -> None:
+        self._postponed_evaluation_enabled = (
+            self._py314_plus or is_postponed_evaluation_enabled(node)
+        )
+
     def _msg_postponed_eval_hint(self, node: nodes.NodeNG) -> str:
         """Message hint if postponed evaluation isn't enabled."""
         if self._py310_plus or "annotations" in node.root().future_imports:
@@ -474,7 +481,7 @@ def _check_broken_noreturn(self, node: nodes.Name | nodes.Attribute) -> None:
             return
 
         if in_type_checking_block(node) or (
-            is_postponed_evaluation_enabled(node)
+            self._postponed_evaluation_enabled
             and is_node_in_type_annotation_context(node)
         ):
             return
@@ -511,7 +518,7 @@ def _check_broken_callable(self, node: nodes.Name | nodes.Attribute) -> None:
     def _broken_callable_location(self, node: nodes.Name | nodes.Attribute) -> bool:
         """Check if node would be a broken location for collections.abc.Callable."""
         if in_type_checking_block(node) or (
-            is_postponed_evaluation_enabled(node)
+            self._postponed_evaluation_enabled
             and is_node_in_type_annotation_context(node)
         ):
             return False

tests/functional/p/postponed/postponed_evaluation_not_activated.py

@@ -3,10 +3,10 @@
 
 class Class:
     @classmethod
-    def from_string(cls, source) -> Class:  # [undefined-variable]
+    def from_string(cls, source) -> Class:  # <3.14:[undefined-variable]
         ...
 
-    def validate_b(self, obj: OtherClass) -> bool:  # [used-before-assignment]
+    def validate_b(self, obj: OtherClass) -> bool:  # <3.14:[used-before-assignment]
         ...
 
 

tests/functional/u/undefined/undefined_variable.314.txt

@@ -0,0 +1,35 @@
+undefined-variable:12:19:12:26::Undefined variable 'unknown':UNDEFINED
+undefined-variable:18:10:18:21:in_method:Undefined variable 'nomoreknown':UNDEFINED
+undefined-variable:21:19:21:31::Undefined variable '__revision__':UNDEFINED
+undefined-variable:23:8:23:20::Undefined variable '__revision__':UNDEFINED
+undefined-variable:27:29:27:37:bad_default:Undefined variable 'unknown2':UNDEFINED
+undefined-variable:30:10:30:14:bad_default:Undefined variable 'xxxx':UNDEFINED
+undefined-variable:31:4:31:10:bad_default:Undefined variable 'augvar':UNDEFINED
+undefined-variable:32:8:32:14:bad_default:Undefined variable 'vardel':UNDEFINED
+undefined-variable:34:19:34:31:<lambda>:Undefined variable 'doesnotexist':UNDEFINED
+undefined-variable:35:23:35:24:<lambda>:Undefined variable 'z':UNDEFINED
+used-before-assignment:38:4:38:9::Using variable 'POUET' before assignment:CONTROL_FLOW
+used-before-assignment:43:4:43:10::Using variable 'POUETT' before assignment:CONTROL_FLOW
+used-before-assignment:48:4:48:11::Using variable 'POUETTT' before assignment:CONTROL_FLOW
+used-before-assignment:56:4:56:9::Using variable 'PLOUF' before assignment:CONTROL_FLOW
+used-before-assignment:65:11:65:14:if_branch_test:Using variable 'xxx' before assignment:HIGH
+used-before-assignment:91:23:91:32:test_arguments:Using variable 'TestClass' before assignment:HIGH
+used-before-assignment:95:16:95:24:TestClass:Using variable 'Ancestor' before assignment:HIGH
+used-before-assignment:98:26:98:35:TestClass.MissingAncestor:Using variable 'Ancestor1' before assignment:HIGH
+used-before-assignment:105:36:105:41:TestClass.test1.UsingBeforeDefinition:Using variable 'Empty' before assignment:HIGH
+undefined-variable:119:10:119:14:Self:Undefined variable 'Self':UNDEFINED
+undefined-variable:135:7:135:10::Undefined variable 'BAT':UNDEFINED
+undefined-variable:136:4:136:7::Undefined variable 'BAT':UNDEFINED
+used-before-assignment:146:31:146:38:KeywordArgument.test1:Using variable 'enabled' before assignment:HIGH
+undefined-variable:149:32:149:40:KeywordArgument.test2:Undefined variable 'disabled':UNDEFINED
+undefined-variable:154:22:154:25:KeywordArgument.<lambda>:Undefined variable 'arg':UNDEFINED
+undefined-variable:166:4:166:13::Undefined variable 'unicode_2':UNDEFINED
+undefined-variable:171:4:171:13::Undefined variable 'unicode_3':UNDEFINED
+undefined-variable:226:25:226:37:LambdaClass4.<lambda>:Undefined variable 'LambdaClass4':UNDEFINED
+undefined-variable:234:25:234:37:LambdaClass5.<lambda>:Undefined variable 'LambdaClass5':UNDEFINED
+undefined-variable:291:18:291:24:not_using_loop_variable_accordingly:Undefined variable 'iteree':UNDEFINED
+undefined-variable:308:27:308:28:undefined_annotation:Undefined variable 'x':UNDEFINED
+used-before-assignment:309:7:309:8:undefined_annotation:Using variable 'x' before assignment:HIGH
+undefined-variable:339:11:339:12:decorated3:Undefined variable 'x':UNDEFINED
+undefined-variable:344:19:344:20:decorated4:Undefined variable 'y':UNDEFINED
+undefined-variable:365:10:365:20:global_var_mixed_assignment:Undefined variable 'GLOBAL_VAR':HIGH

tests/functional/u/undefined/undefined_variable.py

@@ -252,7 +252,7 @@ def onclick(event):
     from datetime import datetime
 
 
-def func_should_fail(_dt: datetime):  # [used-before-assignment]
+def func_should_fail(_dt: datetime):  # <3.14:[used-before-assignment]
     pass
 
 
@@ -374,13 +374,13 @@ def global_var_mixed_assignment():
 
 
 class RepeatedReturnAnnotations:
-    def x(self, o: RepeatedReturnAnnotations) -> bool:  # [undefined-variable]
+    def x(self, o: RepeatedReturnAnnotations) -> bool:  # <3.14:[undefined-variable]
         pass
-    def y(self) -> RepeatedReturnAnnotations:  # [undefined-variable]
+    def y(self) -> RepeatedReturnAnnotations:  # <3.14:[undefined-variable]
         pass
-    def z(self) -> RepeatedReturnAnnotations:  # [undefined-variable]
+    def z(self) -> RepeatedReturnAnnotations:  # <3.14:[undefined-variable]
         pass
 
 class A:
-    def say_hello(self) -> __module__:  # [undefined-variable]
+    def say_hello(self) -> __module__:  # <3.14:[undefined-variable]
         ...

tests/functional/u/undefined/undefined_variable_py30.314.txt

@@ -0,0 +1,9 @@
+undefined-variable:33:34:33:39:Undefined1.InnerScope.test_undefined:Undefined variable 'Undef':UNDEFINED
+undefined-variable:36:25:36:28:Undefined1.InnerScope.test1:Undefined variable 'ABC':UNDEFINED
+undefined-variable:51:28:51:32:FalsePositive342.test_bad:Undefined variable 'trop':UNDEFINED
+undefined-variable:54:31:54:36:FalsePositive342.test_bad1:Undefined variable 'trop1':UNDEFINED
+undefined-variable:57:31:57:36:FalsePositive342.test_bad2:Undefined variable 'trop2':UNDEFINED
+undefined-variable:63:0:63:9:Bad:Undefined variable 'ABCMet':UNDEFINED
+undefined-variable:66:0:66:15:SecondBad:Undefined variable 'ab':UNDEFINED
+undefined-variable:97:53:97:61:InheritingClass:Undefined variable 'variable':UNDEFINED
+undefined-variable:103:0:103:15:Inheritor:Undefined variable 'DefinedTooLate':UNDEFINED

tests/functional/u/undefined/undefined_variable_py30.py

@@ -5,7 +5,7 @@
 class Undefined:
     """ test various annotation problems. """
 
-    def test(self)->Undefined: # [undefined-variable]
+    def test(self)->Undefined: # <3.14:[undefined-variable]
         """ used Undefined, which is Undefined in this scope. """
 
     Undefined = True

tests/functional/u/used/used_before_assignment_nonlocal.314.txt

@@ -0,0 +1,7 @@
+used-before-assignment:17:14:17:17:test_fail.wrap:Using variable 'cnt' before assignment:HIGH
+used-before-assignment:26:14:26:17:test_fail2.wrap:Using variable 'cnt' before assignment:HIGH
+used-before-assignment:90:10:90:18:type_annotation_never_gets_value_despite_nonlocal:Using variable 'some_num' before assignment:HIGH
+used-before-assignment:96:14:96:18:inner_function_lacks_access_to_outer_args.inner:Using variable 'args' before assignment:HIGH
+used-before-assignment:117:18:117:21:nonlocal_in_outer_frame_fail.outer.inner:Using variable 'num' before assignment:HIGH
+possibly-used-before-assignment:149:20:149:28:nonlocal_in_distant_outer_frame_fail.outer.intermediate.inner:Possibly using variable 'callback' before assignment:CONTROL_FLOW
+used-before-assignment:163:14:163:17:nonlocal_after_bad_usage_fail.inner:Using variable 'num' before assignment:HIGH

tests/functional/u/used/used_before_assignment_nonlocal.py

@@ -26,17 +26,17 @@ def wrap():
         cnt = cnt + 1 # [used-before-assignment]
     wrap()
 
-def test_fail3(arg: test_fail4): # [used-before-assignment]
+def test_fail3(arg: test_fail4): # <3.14:[used-before-assignment]
     """ Depends on `test_fail4`, in argument annotation. """
     return arg
-# +1: [used-before-assignment, used-before-assignment]
+# +1:<3.14: [used-before-assignment, used-before-assignment]
 def test_fail4(*args: test_fail5, **kwargs: undefined):
     """ Depends on `test_fail5` and `undefined` in
     variable and named arguments annotations.
     """
     return args, kwargs
 
-def test_fail5()->undefined1: # [used-before-assignment]
+def test_fail5()->undefined1: # <3.14:[used-before-assignment]
     """ Depends on `undefined1` in function return annotation. """
 
 def undefined():

tests/functional/u/used/used_before_assignment_typing.314.txt

@@ -0,0 +1,15 @@
+undefined-variable:79:20:79:27:MyClass.incorrect_default_method:Undefined variable 'MyClass':UNDEFINED
+possibly-used-before-assignment:171:14:171:20:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'bisect' before assignment:INFERENCE
+possibly-used-before-assignment:172:15:172:23:TypeCheckingMultiBranch.defined_in_elif_branch:Possibly using variable 'calendar' 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:181:14:181:19:TypeCheckingMultiBranch.defined_in_nested_if_else:Possibly using variable 'heapq' before assignment:INFERENCE
+used-before-assignment:185:14:185:19:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'types' before assignment:INFERENCE
+used-before-assignment:186:14:186:18:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'copy' before assignment:INFERENCE
+used-before-assignment:187:14:187:21:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'numbers' before assignment:INFERENCE
+used-before-assignment:188:15:188:20:TypeCheckingMultiBranch.defined_in_try_except:Using variable 'array' before assignment:INFERENCE
+used-before-assignment:191:14:191:19:TypeCheckingMultiBranch.defined_in_loops:Using variable 'email' before assignment:INFERENCE
+used-before-assignment:192:14:192:21:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mailbox' before assignment:INFERENCE
+used-before-assignment:193:14:193:23:TypeCheckingMultiBranch.defined_in_loops:Using variable 'mimetypes' before assignment:INFERENCE
+used-before-assignment:197:14:197:22:TypeCheckingMultiBranch.defined_in_with:Using variable 'binascii' before assignment:INFERENCE

tests/functional/u/used/used_before_assignment_typing.py

@@ -1,6 +1,6 @@
 """Tests for used-before-assignment for typing related issues"""
 # pylint: disable=missing-function-docstring,ungrouped-imports,invalid-name
-
+# pylint: disable=line-too-long
 
 from typing import List, NamedTuple, Optional, TYPE_CHECKING
 
@@ -66,12 +66,12 @@ class MyClass:
     """Type annotation or default values for first level methods can't refer to their own class"""
 
     def incorrect_typing_method(
-        self, other: MyClass  # [undefined-variable]
+        self, other: MyClass  # <3.14:[undefined-variable]
     ) -> bool:
         return self == other
 
     def incorrect_nested_typing_method(
-        self, other: List[MyClass]  # [undefined-variable]
+        self, other: List[MyClass]  # <3.14:[undefined-variable]
     ) -> bool:
         return self == other[0]
 
@@ -137,7 +137,7 @@ class MyFourthClass:  # pylint: disable=too-few-public-methods
     """Class to test conditional imports guarded by TYPE_CHECKING two levels
     up then used in function annotation. See https://github.com/pylint-dev/pylint/issues/7539"""
 
-    def is_close(self, comparator: math.isclose, first, second):  # [used-before-assignment]
+    def is_close(self, comparator: math.isclose, first, second):  # <3.14:[used-before-assignment]
         """Conditional imports guarded are only valid for variable annotations."""
         comparator(first, second)
 
@@ -150,7 +150,7 @@ class VariableAnnotationsGuardedByTypeChecking:  # pylint: disable=too-few-publi
     and https://github.com/pylint-dev/pylint/issues/7882
     """
 
-    still_an_error: datetime.date  # [used-before-assignment]
+    still_an_error: datetime.date  # <3.14:[used-before-assignment]
 
     def print_date(self, date) -> None:
         date: datetime.date = date
@@ -167,33 +167,33 @@ class ConditionalImportGuardedWhenUsed:  # pylint: disable=too-few-public-method
 
 class TypeCheckingMultiBranch:  # pylint: disable=too-few-public-methods,unused-variable
     """Test for defines in TYPE_CHECKING if/elif/else branching"""
-    def defined_in_elif_branch(self) -> calendar.Calendar:  # [possibly-used-before-assignment]
+    def defined_in_elif_branch(self) -> calendar.Calendar:  # <3.14:[possibly-used-before-assignment]
         print(bisect)  # [possibly-used-before-assignment]
-        return calendar.Calendar()
+        return calendar.Calendar()  # >=3.14:[possibly-used-before-assignment]
 
     def defined_in_else_branch(self) -> urlopen:
         print(zoneinfo)  # [used-before-assignment]
         print(pprint())  # [used-before-assignment]
         print(collections())  # [used-before-assignment]
         return urlopen
 
-    def defined_in_nested_if_else(self) -> heapq:  # [possibly-used-before-assignment]
-        print(heapq)
+    def defined_in_nested_if_else(self) -> heapq:  # <3.14:[possibly-used-before-assignment]
+        print(heapq)  # >=3.14:[possibly-used-before-assignment]
         return heapq
 
-    def defined_in_try_except(self) -> array:  # [used-before-assignment]
+    def defined_in_try_except(self) -> array:  # <3.14:[used-before-assignment]
         print(types)  # [used-before-assignment]
         print(copy)  # [used-before-assignment]
         print(numbers)  # [used-before-assignment]
-        return array
+        return array  # >=3.14:[used-before-assignment]
 
-    def defined_in_loops(self) -> json:  # [used-before-assignment]
+    def defined_in_loops(self) -> json:  # <3.14:[used-before-assignment]
         print(email)  # [used-before-assignment]
         print(mailbox)  # [used-before-assignment]
         print(mimetypes)  # [used-before-assignment]
         return json
 
-    def defined_in_with(self) -> base64:  # [used-before-assignment]
+    def defined_in_with(self) -> base64:  # <3.14:[used-before-assignment]
         print(binascii)  # [used-before-assignment]
         return base64