Merge branch 'bug/318' into 'master'

Further improve our handling of --select and --ignore

Closes #318

See merge request !187

docs/source/release-notes/3.4.0.rst

@@ -3,6 +3,9 @@
 
 You can view the `3.4.0 milestone`_ on GitLab for more details.
 
+- Refine logic around ``--select`` and ``--ignore`` when combined with the
+  default values for each. (See also `GitLab#318`_)
+
 - Handle spaces as an alternate separate for error codes, e.g.,
   ``--ignore 'E123 E234'``. (See also `GitLab#329`_)
 
@@ -14,6 +17,8 @@ You can view the `3.4.0 milestone`_ on GitLab for more details.
     https://gitlab.com/pycqa/flake8/milestones/18
 
 .. issue links
+.. _GitLab#318:
+    https://gitlab.com/pycqa/flake8/issues/318
 .. _GitLab#329:
     https://gitlab.com/pycqa/flake8/issues/329
 .. _GitLab#330:

src/flake8/style_guide.py

@@ -74,6 +74,10 @@ class StyleGuide(object):
             reverse=True,
         ))
         self._ignored = tuple(sorted(options.ignore, reverse=True))
+        self._using_default_ignore = set(self._ignored) == set(defaults.IGNORE)
+        self._using_default_select = (
+            set(self._selected) == set(defaults.SELECT)
+        )
         self._decision_cache = {}
         self._parsed_diff = {}
 
@@ -135,14 +139,15 @@ class StyleGuide(object):
         ignore = find_first_match(code, self._ignored)
 
         if select and ignore:
+            if self._using_default_ignore and not self._using_default_select:
+                return Decision.Selected
             return find_more_specific(select, ignore)
         if extra_select and ignore:
             return find_more_specific(extra_select, ignore)
-        if select or (extra_select and self._selected == defaults.SELECT):
+        if select or (extra_select and self._using_default_select):
             return Decision.Selected
-        if select is None and extra_select is None and ignore is not None:
+        if (select is None and
-            return Decision.Ignored
+                (extra_select is None or not self._using_default_ignore)):
-        if self._selected != defaults.SELECT and select is None:
             return Decision.Ignored
         return Decision.Selected
 

tests/unit/test_style_guide.py

@@ -125,6 +125,13 @@ def test_is_user_selected_excludes_errors(select_list, error_code):
     (['E41'], ['E2', 'E12', 'E4'], 'E410', style_guide.Decision.Selected),
     (['E'], ['F'], 'E410', style_guide.Decision.Selected),
     (['F'], [], 'E410', style_guide.Decision.Ignored),
+    (['E'], defaults.IGNORE, 'E126', style_guide.Decision.Selected),
+    (['W'], defaults.IGNORE, 'E126', style_guide.Decision.Ignored),
+    (['E'], defaults.IGNORE, 'W391', style_guide.Decision.Ignored),
+    (['E', 'W'], ['E13'], 'E131', style_guide.Decision.Ignored),
+    (defaults.SELECT, ['E13'], 'E131', style_guide.Decision.Ignored),
+    (defaults.SELECT, defaults.IGNORE, 'E126', style_guide.Decision.Ignored),
+    (defaults.SELECT, defaults.IGNORE, 'W391', style_guide.Decision.Selected),
 ])
 def test_should_report_error(select_list, ignore_list, error_code, expected):
     """Verify we decide when to report an error."""
@@ -141,7 +148,7 @@ def test_should_report_error(select_list, ignore_list, error_code, expected):
         (defaults.SELECT, [], ['I1'], [], 'I100',
             style_guide.Decision.Selected),
         (defaults.SELECT, [], ['I1'], [], 'I201',
-            style_guide.Decision.Selected),
+            style_guide.Decision.Ignored),
         (defaults.SELECT, ['I2'], ['I1'], [], 'I101',
             style_guide.Decision.Selected),
         (defaults.SELECT, ['I2'], ['I1'], [], 'I201',
@@ -156,10 +163,22 @@ def test_should_report_error(select_list, ignore_list, error_code, expected):
             style_guide.Decision.Ignored),
         (defaults.SELECT, ['U401'], [], ['U4'], 'U402',
             style_guide.Decision.Selected),
+        (['E', 'W'], ['E13'], [], [], 'E131', style_guide.Decision.Ignored),
+        (['E', 'W'], ['E13'], [], [], 'E126', style_guide.Decision.Selected),
         (['E2'], ['E21'], [], [], 'E221', style_guide.Decision.Selected),
         (['E2'], ['E21'], [], [], 'E212', style_guide.Decision.Ignored),
         (['F', 'W'], ['C90'], ['I1'], [], 'C901',
             style_guide.Decision.Ignored),
+        (['E', 'W'], ['C'], [], [], 'E131',
+            style_guide.Decision.Selected),
+        (defaults.SELECT, defaults.IGNORE, [], ['I'], 'I101',
+            style_guide.Decision.Selected),
+        (defaults.SELECT, defaults.IGNORE, ['G'], ['I'], 'G101',
+            style_guide.Decision.Selected),
+        (defaults.SELECT, ['G1'], ['G'], ['I'], 'G101',
+            style_guide.Decision.Ignored),
+        (defaults.SELECT, ['E126'], [], ['I'], 'I101',
+            style_guide.Decision.Selected),
     ]
 )
 def test_decision_for_logic(select, ignore, extend_select, enabled_extensions,

tox.ini

@@ -25,7 +25,7 @@ deps =
     wheel
 commands =
     python setup.py -qq bdist_wheel
-    pip install --pre --find-links ./dist/ flake8
+    pip install -U --pre --find-links ./dist/ flake8
     flake8 --version
     flake8 src/flake8/ tests/ setup.py