Fix brain dict regression (#2204) (#2207)

Fix regression resulting in ignored pylint settings

We get rid of the immutable instance attributes in AstroidManager,
ensuring that these always mutate the global state instead of
instance's.
This fixes a regression introduced in commit
bbcc58b.

Fixes #2200

(cherry picked from commit b08166b)

Co-authored-by: Josef Kemetmüller <josef.kemetmueller@gmail.com>

Author: github-actions[bot]

ChangeLog

@@ -7,6 +7,11 @@ What's New in astroid 2.16.0?
 Release date: TBA
 
 
+* Fix a regression in 2.12.0 where settings in AstroidManager would be ignored.
+  Most notably this addresses pylint-dev/pylint#7433.
+
+  Refs #2204
+
 
 What's New in astroid 2.15.6?
 =============================

astroid/manager.py

@@ -70,13 +70,27 @@ def __init__(self) -> None:
         self.astroid_cache = AstroidManager.brain["astroid_cache"]
         self._mod_file_cache = AstroidManager.brain["_mod_file_cache"]
         self._failed_import_hooks = AstroidManager.brain["_failed_import_hooks"]
-        self.always_load_extensions = AstroidManager.brain["always_load_extensions"]
-        self.optimize_ast = AstroidManager.brain["optimize_ast"]
         self.extension_package_whitelist = AstroidManager.brain[
             "extension_package_whitelist"
         ]
         self._transform = AstroidManager.brain["_transform"]
 
+    @property
+    def always_load_extensions(self) -> bool:
+        return AstroidManager.brain["always_load_extensions"]
+
+    @always_load_extensions.setter
+    def always_load_extensions(self, value: bool) -> None:
+        AstroidManager.brain["always_load_extensions"] = value
+
+    @property
+    def optimize_ast(self) -> bool:
+        return AstroidManager.brain["optimize_ast"]
+
+    @optimize_ast.setter
+    def optimize_ast(self, value: bool) -> None:
+        AstroidManager.brain["optimize_ast"] = value
+
     @property
     def register_transform(self):
         # This and unregister_transform below are exported for convenience

tests/test_regrtest.py

@@ -9,7 +9,7 @@
 
 import pytest
 
-from astroid import MANAGER, Instance, bases, nodes, parse, test_utils
+from astroid import MANAGER, Instance, bases, manager, nodes, parse, test_utils
 from astroid.builder import AstroidBuilder, _extract_single_node, extract_node
 from astroid.const import PY38_PLUS
 from astroid.context import InferenceContext
@@ -37,6 +37,24 @@ def tearDown(self) -> None:
         sys.path.pop(0)
         sys.path_importer_cache.pop(resources.find("data"), None)
 
+    def test_manager_instance_attributes_reference_global_MANAGER(self) -> None:
+        for expected in (True, False):
+            with mock.patch.dict(
+                manager.AstroidManager.brain,
+                values={"always_load_extensions": expected},
+            ):
+                assert (
+                    MANAGER.always_load_extensions
+                    == manager.AstroidManager.brain["always_load_extensions"]
+                )
+            with mock.patch.dict(
+                manager.AstroidManager.brain,
+                values={"optimize_ast": expected},
+            ):
+                assert (
+                    MANAGER.optimize_ast == manager.AstroidManager.brain["optimize_ast"]
+                )
+
     def test_module_path(self) -> None:
         man = test_utils.brainless_manager()
         mod = man.ast_from_module_name("package.import_package_subpackage_module")
@@ -50,9 +68,9 @@ def test_module_path(self) -> None:
         self.assertEqual(module.name, "package.subpackage.module")
 
     def test_package_sidepackage(self) -> None:
-        manager = test_utils.brainless_manager()
+        brainless_manager = test_utils.brainless_manager()
         assert "package.sidepackage" not in MANAGER.astroid_cache
-        package = manager.ast_from_module_name("absimp")
+        package = brainless_manager.ast_from_module_name("absimp")
         self.assertIsInstance(package, nodes.Module)
         self.assertTrue(package.package)
         subpackage = next(package.getattr("sidepackage")[0].infer())