Check that we disable pylint messages by name and not code

setup.py

@@ -50,6 +50,7 @@ def get_version():
             'pytest',
             'pytest-randomly',
             'mypy; python_version >= "3.3"',
+            'mock; python_version < "3.3"',
         ]
     }
 )

shopify_python/__init__.py

@@ -4,10 +4,12 @@
 
 from pylint import lint
 from shopify_python import google_styleguide
+from shopify_python import shopify_styleguide
 
 
 __version__ = '0.1.2'
 
 
 def register(linter):  # type: (lint.PyLinter) -> None
     google_styleguide.register_checkers(linter)
+    shopify_styleguide.register_checkers(linter)

shopify_python/shopify_styleguide.py

@@ -0,0 +1,53 @@
+import re
+import tokenize
+import typing  # pylint: disable=unused-import
+
+import pylint.utils
+
+from pylint import checkers
+from pylint import interfaces
+from pylint import lint  # pylint: disable=unused-import
+
+
+def register_checkers(linter):  # type: (lint.PyLinter) -> None
+    """Register checkers."""
+    linter.register_checker(ShopifyStyleGuideChecker(linter))
+
+
+class ShopifyStyleGuideChecker(checkers.BaseTokenChecker):
+    """
+    Pylint checker for Shopify-specific Code Style.
+    """
+    __implements__ = (interfaces.ITokenChecker,)
+
+    name = 'shopify-styleguide-checker'
+
+    msgs = {
+        'C6101': ("%(code)s disabled as a message code, use '%(name)s' instead",
+                  'disable-name-only',
+                  "Disable pylint rules via message name (e.g. unused-import) and not message code (e.g. W0611) to "
+                  "help code reviewers understand why a linter rule was disabled for a line of code."),
+    }
+
+    RE_PYLINT_DISABLE = re.compile(r'^#[ \t]*pylint:[ \t]*(disable|enable)[ \t]*=(?P<messages>[a-zA-Z0-9\-_, \t]+)$')
+    RE_PYLINT_MESSAGE_CODE = re.compile(r'^[A-Z]{1,2}[0-9]{4}$')
+
+    def process_tokens(self, tokens):
+        # type: (typing.Sequence[typing.Tuple]) -> None
+        for _type, string, start, _, _ in tokens:
+            start_row, _ = start
+            if _type == tokenize.COMMENT:
+
+                def get_name(code):
+                    try:
+                        return self.linter.msgs_store.get_msg_display_string(code)
+                    except pylint.utils.UnknownMessage:
+                        return 'unknown'
+
+                matches = self.RE_PYLINT_DISABLE.match(string)
+                if matches:
+                    for msg in matches.group('messages').split(','):
+                        msg = msg.strip()
+                        if self.RE_PYLINT_MESSAGE_CODE.match(msg):
+                            self.add_message('disable-name-only', line=start_row,
+                                             args={'code': msg, 'name': get_name(msg)})

tests/shopify_python/test_shopify_styleguide.py

@@ -0,0 +1,55 @@
+import pylint.testutils
+
+try:
+    import unittest.mock as mock  # Python 3.3+
+except ImportError:
+    import mock  # Python < 3.3
+
+from shopify_python import shopify_styleguide
+
+
+class TestShopifyStyleGuideChecker(pylint.testutils.CheckerTestCase):
+
+    CHECKER_CLASS = shopify_styleguide.ShopifyStyleGuideChecker
+
+    def test_disable_name_only(self):
+
+        # Patch 'msgs_store'
+        mock_msgs_store = mock.Mock()
+        mock_msgs_store.get_msg_display_string = mock.Mock()
+        mock_msgs_store.get_msg_display_string.return_value = 'mocked'
+        setattr(self.linter, 'msgs_store', mock_msgs_store)
+
+        # Create tokens
+        tokens = pylint.testutils.tokenize_str("""
+        import os  # pylint: disable=unused-import
+        import os  # pylint: disable=unused-import,W0611
+        import os  # pylint: disable=W0611,C0302,C0303
+        import os  # pylint: disable=W0611
+        import os  #pylint:disable=W0611
+        import os  #  pylint:\t\t  disable  \t\t    = \t\t W0611
+        def fnc():
+            # pylint: disable=C0112
+            pass
+        """.strip())
+
+        # Expected
+        expected_line_msgcodes = [
+            (2, 'W0611'),
+            (3, 'W0611'),
+            (3, 'C0302'),
+            (3, 'C0303'),
+            (4, 'W0611'),
+            (5, 'W0611'),
+            (6, 'W0611'),
+            (8, 'C0112'),
+        ]
+
+        # Test
+        with self.assertAddsMessages(*[
+            pylint.testutils.Message('disable-name-only', line=line, args={'code': code, 'name': 'mocked'})
+            for line, code in expected_line_msgcodes
+        ]):
+            self.checker.process_tokens(tokens)
+        mock_msgs_store.get_msg_display_string.assert_has_calls(
+            [mock.call(code) for _, code in expected_line_msgcodes])