[Backport maintenance/4.0.x] Fix unused-variable false positive with __all__ or __future__.annotations (#10653)

Fix `unused-variable` false positive with `__all__` or `__future__.annotations` (#10643)

(cherry picked from commit bbbdb9d)

Co-authored-by: Mark Byrne <[email protected]>

Author: pylint-backport[bot]

doc/whatsnew/fragments/10019.false_positive

@@ -0,0 +1,3 @@
+Exclude ``__all__`` and ``__future__.annotations`` from ``unused-variable``.
+
+Closes #10019

pylint/checkers/variables.py

@@ -3285,6 +3285,14 @@ def _check_globals(self, not_consumed: Consumption) -> None:
                     continue
                 if self._is_exception_binding_used_in_handler(node, name):
                     continue
+                if isinstance(node, nodes.AssignName) and node.name == "__all__":
+                    continue
+                if (
+                    isinstance(node, nodes.ImportFrom)
+                    and name == "annotations"
+                    and node.modname == "__future__"
+                ):
+                    continue
                 self.add_message("unused-variable", args=(name,), node=node)
 
     # pylint: disable = too-many-branches

tests/functional/u/unused/unused_variable_future_and_annotations.py

@@ -0,0 +1,11 @@
+"""Test `unused-variable` is not emitted for either case of `__future__.annotations` or `__all__`"""
+
+
+from __future__ import annotations
+
+
+__all__ = [ "apple" ]
+
+
+def apple():
+    """A public function"""

tests/functional/u/unused/unused_variable_future_and_annotations.rc

@@ -0,0 +1,2 @@
+[variables]
+allow-global-unused-variables=no