Merge branch 'bug/195' into 'master'

Allow plugins that are on by default to be ignored

*Description of changes*

Previously, users were unable to ignore the error code of a plugin that was on by default. This adds a tiny bit of extra logic to re-enable that behaviour.

*Related to:*  #195

See merge request !104

docs/source/release-notes/3.0.3.rst

@@ -4,7 +4,11 @@
 - Fix ``# noqa`` comments followed by a ``:`` and explanation broken by
   3.0.0 (See also `GitLab#178`_)
 
+- Fix issue where users were unable to ignore plugin errors that were on
+  by default. (See also `GitLab#195`_)
 
 .. links
 .. _GitLab#178:
     https://gitlab.com/pycqa/flake8/issues/178
+.. _GitLab#195:
+    https://gitlab.com/pycqa/flake8/issues/195

src/flake8/options/aggregator.py

@@ -53,14 +53,12 @@ def aggregate_options(manager, arglist=None, values=None):
               list(extended_default_ignore))
     extended_default_ignore.update(default_values.ignore)
     default_values.ignore = list(extended_default_ignore)
+    LOG.debug('Merged default ignore list: %s', default_values.ignore)
 
     extended_default_select = manager.extended_default_select.copy()
     LOG.debug('Extended default select list: %s',
               list(extended_default_select))
-    extended_default_select.update(default_values.select)
-    default_values.select = list(extended_default_select)
-    LOG.debug('Merged default ignore list: %s', default_values.ignore)
-    LOG.debug('Merged default select list: %s', default_values.select)
+    default_values.extended_default_select = extended_default_select
 
     # Merge values parsed from config onto the default values returned
     for config_name, value in parsed_config.items():

src/flake8/style_guide.py

@@ -63,6 +63,7 @@ class StyleGuide(object):
         self.formatter = formatter
         self.stats = statistics.Statistics()
         self._selected = tuple(options.select)
+        self._extended_selected = tuple(options.extended_default_select)
         self._ignored = tuple(options.ignore)
         self._decision_cache = {}
         self._parsed_diff = {}
@@ -86,6 +87,13 @@ class StyleGuide(object):
         if code.startswith(self._selected):
             return Selected.Explicitly
 
+        # If it was not explicitly selected, it may have been implicitly
+        # selected because the check comes from a plugin that is enabled by
+        # default
+        if (self._extended_selected and
+                code.startswith(self._extended_selected)):
+            return Selected.Implicitly
+
         return Ignored.Implicitly
 
     def is_user_ignored(self, code):

tests/unit/test_style_guide.py

@@ -12,6 +12,7 @@ from flake8.plugins import notifier
 def create_options(**kwargs):
     """Create and return an instance of optparse.Values."""
     kwargs.setdefault('select', [])
+    kwargs.setdefault('extended_default_select', [])
     kwargs.setdefault('ignore', [])
     kwargs.setdefault('disable_noqa', False)
     return optparse.Values(kwargs)