False positive global-variable-not-assigned (#7479)

* Fix false positive for ``global-variable-not-assigned`` when a global variable is re-assigned via a ``ImportFrom`` node.

Closes #4809

Co-authored-by: Jacob Walls <[email protected]>

Author: 2 people

doc/whatsnew/fragments/4809.false_positive

@@ -0,0 +1,3 @@
+Fix false positive for ``global-variable-not-assigned`` when a global variable is re-assigned via an ``ImportFrom`` node.
+
+Closes #4809

pylint/checkers/variables.py

@@ -1311,7 +1311,8 @@ def visit_global(self, node: nodes.Global) -> None:
                 assign_nodes = []
 
             not_defined_locally_by_import = not any(
-                isinstance(local, nodes.Import) for local in locals_.get(name, ())
+                isinstance(local, (nodes.Import, nodes.ImportFrom))
+                for local in locals_.get(name, ())
             )
             if (
                 not utils.is_reassigned_after_current(node, name)

tests/functional/g/globals.py

@@ -31,9 +31,15 @@ def define_constant():
 
 
 def global_with_import():
-    """should only warn for global-statement"""
+    """should only warn for global-statement when using `Import` node"""
     global sys  # [global-statement]
-    import sys  # pylint: disable=import-outside-toplevel
+    import sys
+
+
+def global_with_import_from():
+    """should only warn for global-statement when using `ImportFrom` node"""
+    global namedtuple  # [global-statement]
+    from collections import namedtuple
 
 
 def global_no_assign():
@@ -75,11 +81,6 @@ def FUNC():
 
     FUNC()
 
-def func():
-    """Overriding a global with an import should only throw a global statement error"""
-    global sys  # [global-statement]
-
-    import sys
 
 def override_class():
     """Overriding a class should only throw a global statement error"""

tests/functional/g/globals.txt

@@ -5,10 +5,10 @@ global-variable-not-assigned:23:4:23:14:other:Using global for 'HOP' but no assi
 undefined-variable:24:10:24:13:other:Undefined variable 'HOP':UNDEFINED
 global-variable-undefined:29:4:29:18:define_constant:Global variable 'SOMEVAR' undefined at the module level:UNDEFINED
 global-statement:35:4:35:14:global_with_import:Using the global statement:UNDEFINED
-global-variable-not-assigned:41:4:41:19:global_no_assign:Using global for 'CONSTANT' but no assignment is done:UNDEFINED
-global-statement:47:4:47:19:global_del:Using the global statement:UNDEFINED
-global-statement:54:4:54:19:global_operator_assign:Using the global statement:UNDEFINED
-global-statement:61:4:61:19:global_function_assign:Using the global statement:UNDEFINED
-global-statement:71:4:71:15:override_func:Using the global statement:UNDEFINED
-global-statement:80:4:80:14:func:Using the global statement:UNDEFINED
-global-statement:86:4:86:16:override_class:Using the global statement:UNDEFINED
+global-statement:41:4:41:21:global_with_import_from:Using the global statement:UNDEFINED
+global-variable-not-assigned:47:4:47:19:global_no_assign:Using global for 'CONSTANT' but no assignment is done:UNDEFINED
+global-statement:53:4:53:19:global_del:Using the global statement:UNDEFINED
+global-statement:60:4:60:19:global_operator_assign:Using the global statement:UNDEFINED
+global-statement:67:4:67:19:global_function_assign:Using the global statement:UNDEFINED
+global-statement:77:4:77:15:override_func:Using the global statement:UNDEFINED
+global-statement:87:4:87:16:override_class:Using the global statement:UNDEFINED

tests/functional/u/unused/unused_variable.py

@@ -94,7 +94,7 @@ def test_global():
     variables through imports.
     """
     # pylint: disable=redefined-outer-name
-    global PATH, OS, collections, deque  # [global-variable-not-assigned, global-variable-not-assigned]
+    global PATH, OS, collections, deque  # [global-statement]
     from os import path as PATH
     import os as OS
     import collections

tests/functional/u/unused/unused_variable.txt

@@ -13,8 +13,7 @@ unused-import:55:4:55:38:unused_import_from:Unused namedtuple imported from coll
 unused-import:59:4:59:40:unused_import_in_function:Unused hexdigits imported from string:UNDEFINED
 unused-variable:64:4:64:10:hello:Unused variable 'my_var':UNDEFINED
 unused-variable:75:4:75:8:function:Unused variable 'aaaa':UNDEFINED
-global-variable-not-assigned:97:4:97:39:test_global:Using global for 'PATH' but no assignment is done:UNDEFINED
-global-variable-not-assigned:97:4:97:39:test_global:Using global for 'deque' but no assignment is done:UNDEFINED
+global-statement:97:4:97:39:test_global:Using the global statement:UNDEFINED
 unused-import:103:4:103:28:test_global:Unused platform imported from sys:UNDEFINED
 unused-import:104:4:104:38:test_global:Unused version imported from sys as VERSION:UNDEFINED
 unused-import:105:4:105:15:test_global:Unused import this:UNDEFINED