Fixed false positive for global-variable-undefined

ChangeLog

@@ -40,7 +40,9 @@ Release date: TBA
 * Fixed false positive ``consider-using-dict-comprehension`` when creating a dict
   using a list of tuples where key AND value vary depending on the same condition.
 
-  Closes #5588
+* Fixed false positive for ``global-variable-undefined`` when ``global`` is used with a class name
+
+  Closes #3088
 
 * Added ``lru-cache-decorating-method`` checker with checks for the use of ``functools.lru_cache``
   on class methods. This is unrecommended as it creates memory leaks by never letting the instance

doc/whatsnew/2.13.rst

@@ -94,6 +94,10 @@ Other Changes
 * When run in parallel mode ``pylint`` now pickles the data passed to subprocesses with
   the ``dill`` package. The ``dill`` package has therefore been added as a dependency.
 
+* Fixed false positive for ``global-variable-undefined`` when ``global`` is used with a class name
+
+  Closes #3088
+
 * Fixed crash on properties and inherited class methods when comparing them for
   equality against an empty dict.
 

pylint/checkers/utils.py

@@ -1668,7 +1668,9 @@ def is_reassigned_after_current(node: nodes.NodeNG, varname: str) -> bool:
     """Check if the given variable name is reassigned in the same scope after the current node"""
     return any(
         a.name == varname and a.lineno > node.lineno
-        for a in node.scope().nodes_of_class((nodes.AssignName, nodes.FunctionDef))
+        for a in node.scope().nodes_of_class(
+            (nodes.AssignName, nodes.ClassDef, nodes.FunctionDef)
+        )
     )
 
 

pylint/checkers/variables.py

@@ -1205,7 +1205,10 @@ def visit_global(self, node: nodes.Global) -> None:
                 if anode.frame(future=True) is module:
                     # module level assignment
                     break
-                if isinstance(anode, nodes.FunctionDef) and anode.parent is module:
+                if (
+                    isinstance(anode, (nodes.ClassDef, nodes.FunctionDef))
+                    and anode.parent is module
+                ):
                     # module level function assignment
                     break
             else:

tests/functional/g/globals.py

@@ -1,5 +1,5 @@
 """Warnings about global statements and usage of global variables."""
-# pylint: disable=invalid-name, redefined-outer-name, missing-function-docstring, import-outside-toplevel
+# pylint: disable=invalid-name, redefined-outer-name, missing-function-docstring, missing-class-docstring, import-outside-toplevel, too-few-public-methods
 from __future__ import print_function
 
 global CSTE  # [global-at-module-level]
@@ -9,6 +9,9 @@
 def FUNC():
     pass
 
+class CLASS:
+    pass
+
 def fix_contant(value):
     """all this is ok, but try not using global ;)"""
     global CONSTANT  # [global-statement]
@@ -78,3 +81,12 @@ def func():
     global sys  # [global-statement]
 
     import sys
+
+def override_class():
+    """Overriding a class should only throw a global statement error"""
+    global CLASS  # [global-statement]
+
+    class CLASS():
+        pass
+
+    CLASS()

tests/functional/g/globals.txt

@@ -1,13 +1,14 @@
 global-at-module-level:5:0:5:11::Using the global statement at the module level:UNDEFINED
 undefined-variable:6:6:6:10::Undefined variable 'CSTE':UNDEFINED
-global-statement:14:4:14:19:fix_contant:Using the global statement:UNDEFINED
-global-variable-not-assigned:21:4:21:14:other:Using global for 'HOP' but no assignment is done:UNDEFINED
-undefined-variable:22:10:22:13:other:Undefined variable 'HOP':UNDEFINED
-global-variable-undefined:27:4:27:18:define_constant:Global variable 'SOMEVAR' undefined at the module level:UNDEFINED
-global-statement:33:4:33:14:global_with_import:Using the global statement:UNDEFINED
-global-variable-not-assigned:39:4:39:19:global_no_assign:Using global for 'CONSTANT' but no assignment is done:UNDEFINED
-global-statement:45:4:45:19:global_del:Using the global statement:UNDEFINED
-global-statement:52:4:52:19:global_operator_assign:Using the global statement:UNDEFINED
-global-statement:59:4:59:19:global_function_assign:Using the global statement:UNDEFINED
-global-statement:69:4:69:15:override_func:Using the global statement:UNDEFINED
-global-statement:78:4:78:14:func:Using the global statement:UNDEFINED
+global-statement:17:4:17:19:fix_contant:Using the global statement:UNDEFINED
+global-variable-not-assigned:24:4:24:14:other:Using global for 'HOP' but no assignment is done:UNDEFINED
+undefined-variable:25:10:25:13:other:Undefined variable 'HOP':UNDEFINED
+global-variable-undefined:30:4:30:18:define_constant:Global variable 'SOMEVAR' undefined at the module level:UNDEFINED
+global-statement:36:4:36:14:global_with_import:Using the global statement:UNDEFINED
+global-variable-not-assigned:42:4:42:19:global_no_assign:Using global for 'CONSTANT' but no assignment is done:UNDEFINED
+global-statement:48:4:48:19:global_del:Using the global statement:UNDEFINED
+global-statement:55:4:55:19:global_operator_assign:Using the global statement:UNDEFINED
+global-statement:62:4:62:19:global_function_assign:Using the global statement:UNDEFINED
+global-statement:72:4:72:15:override_func:Using the global statement:UNDEFINED
+global-statement:81:4:81:14:func:Using the global statement:UNDEFINED
+global-statement:87:4:87:16:override_class:Using the global statement:UNDEFINED