Merge branch 'extend_select' into 'master'

Add --extend-select command line argument

See merge request pycqa/flake8!437

docs/source/user/invocation.rst

@@ -115,6 +115,10 @@ And you should see something like:
                             run. (Default: 79)
       --select=errors       Comma-separated list of errors and warnings to enable.
                             For example, ``--select=E4,E51,W234``. (Default: )
+      --extend-select errors
+                            Comma-separated list of errors and warnings to add to
+                            the list of selected ones. For example, ``--extend-
+                            select=E4,E51,W234``.
       --disable-noqa        Disable the effect of "# noqa". This will report
                             errors on lines with "# noqa" at the end.
       --show-source         Show the source generate each error or warning.

docs/source/user/options.rst

@@ -68,6 +68,8 @@ Index of Options
 
 - :option:`flake8 --select`
 
+- :option:`flake8 --extend-select`
+
 - :option:`flake8 --disable-noqa`
 
 - :option:`flake8 --show-source`
@@ -632,6 +634,38 @@ Options and their Descriptions
             F
 
 
+.. option:: --extend-select=<errors>
+
+    :ref:`Go back to index <top>`
+
+    .. versionadded:: 3.9.0
+
+    Specify a list of codes to add to the list of selected ones. Similar
+    considerations as in :option:`--select` apply here with regard to the
+    value.
+
+    The difference to the :option:`--select` option is, that this option can be
+    used to selectively add individual codes without overriding the default
+    list entirely.
+
+    Command-line example:
+
+    .. prompt:: bash
+
+        flake8 --extend-select=E4,E51,W234 dir/
+
+    This **can** be specified in config files.
+
+    Example config file usage:
+
+    .. code-block:: ini
+
+        extend-select =
+            E4,
+            E51,
+            W234
+
+
 .. option:: --disable-noqa
 
     :ref:`Go back to index <top>`

src/flake8/main/options.py

@@ -105,6 +105,7 @@ def register_default_options(option_manager):
     - ``--max-doc-length``
     - ``--indent-size``
     - ``--select``
+    - ``--extend-select``
     - ``--disable-noqa``
     - ``--show-source``
     - ``--statistics``
@@ -272,6 +273,16 @@ def register_default_options(option_manager):
         " For example, ``--select=E4,E51,W234``. (Default: %(default)s)",
     )
 
+    add_option(
+        "--extend-select",
+        metavar="errors",
+        default="",
+        parse_from_config=True,
+        comma_separated_list=True,
+        help="Comma-separated list of errors and warnings to add to the list"
+        " of selected ones. For example, ``--extend-select=E4,E51,W234``.",
+    )
+
     add_option(
         "--disable-noqa",
         default=False,

src/flake8/style_guide.py

@@ -163,7 +163,14 @@ class DecisionEngine:
         )
         self.enabled_extensions = tuple(options.enable_extensions)
         self.all_selected = tuple(
-            sorted(self.selected + self.enabled_extensions, reverse=True)
+            sorted(
+                itertools.chain(
+                    self.selected,
+                    options.extend_select,
+                    self.enabled_extensions,
+                ),
+                reverse=True,
+            )
         )
         self.ignored = tuple(
             sorted(

tests/unit/test_decision_engine.py

@@ -11,6 +11,7 @@ def create_options(**kwargs):
     """Create and return an instance of argparse.Namespace."""
     kwargs.setdefault('select', [])
     kwargs.setdefault('extended_default_select', [])
+    kwargs.setdefault('extend_select', [])
     kwargs.setdefault('ignore', [])
     kwargs.setdefault('extend_ignore', [])
     kwargs.setdefault('disable_noqa', False)
@@ -52,20 +53,27 @@ def test_was_ignored_implicitly_selects_errors(ignore_list, extend_ignore,
     assert decider.was_ignored(error_code) is style_guide.Selected.Implicitly
 
 
-@pytest.mark.parametrize('select_list,enable_extensions,error_code', [
+@pytest.mark.parametrize(
-    (['E111', 'E121'], [], 'E111'),
+    'select_list,extend_select,enable_extensions,error_code', [
-    (['E111', 'E121'], [], 'E121'),
+        (['E111', 'E121'], [], [], 'E111'),
-    (['E11', 'E12'], [], 'E121'),
+        (['E111', 'E121'], [], [], 'E121'),
-    (['E2', 'E12'], [], 'E121'),
+        (['E11', 'E12'], [], [], 'E121'),
-    (['E2', 'E12'], [], 'E211'),
+        (['E2', 'E12'], [], [], 'E121'),
-    (['E1'], ['E2'], 'E211'),
+        (['E2', 'E12'], [], [], 'E211'),
-    ([], ['E2'], 'E211'),
+        (['E1'], ['E2'], [], 'E211'),
-])
+        (['E1'], [], ['E2'], 'E211'),
-def test_was_selected_selects_errors(select_list, enable_extensions,
+        ([], ['E2'], [], 'E211'),
-                                     error_code):
+        ([], [], ['E2'], 'E211'),
+        (['E1'], ['E2'], [], 'E211'),
+        (['E111'], ['E121'], ['E2'], 'E121'),
+    ]
+)
+def test_was_selected_selects_errors(select_list, extend_select,
+                                     enable_extensions, error_code):
     """Verify we detect users explicitly selecting an error."""
     decider = style_guide.DecisionEngine(
         options=create_options(select=select_list,
+                               extend_select=extend_select,
                                enable_extensions=enable_extensions),
     )
 
@@ -144,7 +152,8 @@ def test_decision_for(select_list, ignore_list, extend_ignore, error_code,
 
 
 @pytest.mark.parametrize(
-    'select,ignore,extend_select,enabled_extensions,error_code,expected', [
+    'select,ignore,extended_default_select,'
+    'enabled_extensions,error_code,expected', [
         (defaults.SELECT, [], ['I1'], [], 'I100',
             style_guide.Decision.Selected),
         (defaults.SELECT, [], ['I1'], [], 'I201',
@@ -185,14 +194,14 @@ def test_decision_for(select_list, ignore_list, extend_ignore, error_code,
         # return statement
     ]
 )
-def test_more_specific_decision_for_logic(select, ignore, extend_select,
+def test_more_specific_decision_for_logic(
-                                          enabled_extensions, error_code,
+        select, ignore, extended_default_select,
-                                          expected):
+        enabled_extensions, error_code, expected):
     """Verify the logic of DecisionEngine.more_specific_decision_for."""
     decider = style_guide.DecisionEngine(
         create_options(
             select=select, ignore=ignore,
-            extended_default_select=extend_select,
+            extended_default_select=extended_default_select,
             enable_extensions=enabled_extensions,
         ),
     )

tests/unit/test_style_guide.py

@@ -14,6 +14,7 @@ def create_options(**kwargs):
     """Create and return an instance of argparse.Namespace."""
     kwargs.setdefault('select', [])
     kwargs.setdefault('extended_default_select', [])
+    kwargs.setdefault('extend_select', [])
     kwargs.setdefault('ignore', [])
     kwargs.setdefault('extend_ignore', [])
     kwargs.setdefault('disable_noqa', False)