Move checker initialization and closing into context manager

pylint/lint.py

@@ -1102,36 +1102,9 @@ def _check_files(self, get_ast, file_descrs):
         - filepath: path of the file
         - modname: module name
         """
-        walker = ASTWalker(self)
-        _checkers = self.prepare_checkers()
-        tokencheckers = [
-            c
-            for c in _checkers
-            if interfaces.implements(c, interfaces.ITokenChecker) and c is not self
-        ]
-        rawcheckers = [
-            c for c in _checkers if interfaces.implements(c, interfaces.IRawChecker)
-        ]
-        # notify global begin
-        for checker in _checkers:
-            checker.open()
-            if interfaces.implements(checker, interfaces.IAstroidChecker):
-                walker.add_checker(checker)
-
-        check_astroid_module = functools.partial(
-            self.check_astroid_module,
-            walker=walker,
-            tokencheckers=tokencheckers,
-            rawcheckers=rawcheckers,
-        )
-
-        for name, filepath, modname in file_descrs:
-            self._check_file(get_ast, check_astroid_module, name, filepath, modname)
-
-        # notify global end
-        self.stats["statement"] = walker.nbstatements
-        for checker in reversed(_checkers):
-            checker.close()
+        with self._astroid_module_checker() as check_astroid_module:
+            for name, filepath, modname in file_descrs:
+                self._check_file(get_ast, check_astroid_module, name, filepath, modname)
 
     def _check_file(self, get_ast, check_astroid_module, name, filepath, modname):
         self.set_current_module(name, filepath)
@@ -1201,6 +1174,36 @@ def set_current_module(self, modname, filepath=None):
         for msg_cat in MSG_TYPES.values():
             self.stats["by_module"][modname][msg_cat] = 0
 
+    @contextlib.contextmanager
+    def _astroid_module_checker(self):
+        walker = ASTWalker(self)
+        _checkers = self.prepare_checkers()
+        tokencheckers = [
+            c
+            for c in _checkers
+            if interfaces.implements(c, interfaces.ITokenChecker) and c is not self
+        ]
+        rawcheckers = [
+            c for c in _checkers if interfaces.implements(c, interfaces.IRawChecker)
+        ]
+        # notify global begin
+        for checker in _checkers:
+            checker.open()
+            if interfaces.implements(checker, interfaces.IAstroidChecker):
+                walker.add_checker(checker)
+
+        yield functools.partial(
+            self.check_astroid_module,
+            walker=walker,
+            tokencheckers=tokencheckers,
+            rawcheckers=rawcheckers,
+        )
+
+        # notify global end
+        self.stats["statement"] = walker.nbstatements
+        for checker in reversed(_checkers):
+            checker.close()
+
     def get_ast(self, filepath, modname):
         """return an ast(roid) representation for a module"""
         try: