refactor run_checks to not take an Optional list of filenames

src/flake8/api/legacy.py

@@ -103,7 +103,8 @@ class StyleGuide:
         :rtype:
             flake8.api.legacy.Report
         """
-        self._application.run_checks(paths)
+        self._application.options.filenames = paths
+        self._application.run_checks()
         self._application.report_errors()
         return Report(self._application)
 

src/flake8/checker.py

@@ -56,21 +56,18 @@ class Manager:
       together and make our output deterministic.
     """
 
-    def __init__(self, style_guide, arguments, checker_plugins):
+    def __init__(self, style_guide, checker_plugins):
         """Initialize our Manager instance.
 
         :param style_guide:
             The instantiated style guide for this instance of Flake8.
         :type style_guide:
             flake8.style_guide.StyleGuide
-        :param list arguments:
-            The extra arguments parsed from the CLI (if any)
         :param checker_plugins:
             The plugins representing checks parsed from entry-points.
         :type checker_plugins:
             flake8.plugins.manager.Checkers
         """
-        self.arguments = arguments
         self.style_guide = style_guide
         self.options = style_guide.options
         self.checks = checker_plugins
@@ -112,7 +109,7 @@ class Manager:
             )
             return 0
 
-        if utils.is_using_stdin(self.arguments):
+        if utils.is_using_stdin(self.options.filenames):
             LOG.warning(
                 "The --jobs option is not compatible with supplying "
                 "input using - . Ignoring --jobs arguments."
@@ -159,7 +156,7 @@ class Manager:
     def make_checkers(self, paths: Optional[List[str]] = None) -> None:
         """Create checkers for each file."""
         if paths is None:
-            paths = self.arguments
+            paths = self.options.filenames
 
         checks = self.checks.to_dictionary()
         self._all_checkers = [

src/flake8/main/application.py

@@ -246,28 +246,25 @@ class Application:
 
     def make_file_checker_manager(self) -> None:
         """Initialize our FileChecker Manager."""
-        assert self.options is not None
         self.file_checker_manager = checker.Manager(
             style_guide=self.guide,
-            arguments=self.options.filenames,
             checker_plugins=self.check_plugins,
         )
 
-    def run_checks(self, files: Optional[List[str]] = None) -> None:
+    def run_checks(self) -> None:
         """Run the actual checks with the FileChecker Manager.
 
         This method encapsulates the logic to make a
         :class:`~flake8.checker.Manger` instance run the checks it is
         managing.
-
-        :param list files:
-            List of filenames to process
         """
         assert self.file_checker_manager is not None
         if self.running_against_diff:
-            files = sorted(self.parsed_diff)
+            files: Optional[List[str]] = sorted(self.parsed_diff)
             if not files:
                 return
+        else:
+            files = None
 
         self.file_checker_manager.start(files)
         try: