Changes to make ament_flake8 work with v6+ (#459) (#464)

* Changes to make ament_flake8 work with v6+

* Correct make_file_checker_manager call

* Fix compatibility with flake8 5.

Signed-off-by: Michael Carroll <mjcarroll@intrinsic.ai>
Signed-off-by: Chris Lalancette <clalancette@gmail.com>
(cherry picked from commit fc02432)

Co-authored-by: Michael Carroll <mjcarroll@intrinsic.ai>

ament_flake8/ament_flake8/main.py

@@ -143,6 +143,7 @@ def get_flake8_style_guide(argv):
     # appropriate options to pass into the standard flake8.legacy.get_style_guide();
     # passing argv gets it to determine the options for us.
     application = flake8_app.Application()
+    file_checker_takes_argv = False
     if hasattr(application, 'parse_preliminary_options'):
         prelim_opts, remaining_args = application.parse_preliminary_options(
             argv)
@@ -170,22 +171,32 @@ def get_flake8_style_guide(argv):
             )
             application.register_plugin_options()
             application.parse_configuration_and_cli(cfg, cfg_dir, remaining_args)
-    else:
+    elif hasattr(application, 'parse_preliminary_options_and_args'):
         application.parse_preliminary_options_and_args([])
         flake8.configure_logging(
             application.prelim_opts.verbose, application.prelim_opts.output_file)
         application.make_config_finder()
         application.find_plugins()
         application.register_plugin_options()
         application.parse_configuration_and_cli(argv)
+    else:
+        # Flake8 >= 6 uses parse_args
+        # Ref: https://github.com/PyCQA/flake8/commit/0d667a73299971f1cf8ff549c519fffb282b1faf
+        from flake8.options.parse_args import parse_args
+        application.plugins, application.options = parse_args(argv)
+        file_checker_takes_argv = True
     application.make_formatter()
     try:
         # needed in older flake8 versions to populate the listener
         application.make_notifier()
     except AttributeError:
         pass
     application.make_guide()
-    application.make_file_checker_manager()
+
+    if file_checker_takes_argv:
+        application.make_file_checker_manager(argv)
+    else:
+        application.make_file_checker_manager()
     return StyleGuide(application)
 
 
@@ -196,11 +207,19 @@ def parse_config_file(config_file):
     major_release = flake8_version_info[0]
 
     if major_release >= 5:
-        opts_manager = manager.OptionManager(
-            version=flake8_version,
-            plugin_versions='',
-            parents=[]
-        )
+        if major_release == 5:
+            opts_manager = manager.OptionManager(
+                version=flake8_version,
+                plugin_versions='',
+                parents=[],
+            )
+        else:
+            opts_manager = manager.OptionManager(
+                version=flake8_version,
+                plugin_versions='',
+                parents=[],
+                formatter_names=[],
+            )
         flake8_options.register_default_options(opts_manager)
         cfg, cfg_dir = config.load_config(config_file, [])
 
@@ -260,8 +279,13 @@ def custom_format(error):
 
     # Get the names of files checked
     report.report = style.check_files(paths)
-    file_checkers = style._application.file_checker_manager.checkers
-    report.files = [file_checker.filename for file_checker in file_checkers]
+
+    # Flake8 < 6 uses 'checkers' attribute
+    if hasattr(style._application.file_checker_manager, 'checkers'):
+        file_checkers = style._application.file_checker_manager.checkers
+        report.files = [file_checker.filename for file_checker in file_checkers]
+    else:
+        report.files = style._application.file_checker_manager.filenames
 
     assert report.report.total_errors == len(report.errors)
     return report