Do not pass noqa to plugins, have flake8 decide whether to report

src/flake8/processor.py

@@ -47,6 +47,9 @@ class FileProcessor(object):
     - :attr:`verbose`
     """
 
+    #: always ``False``, included for compatibility
+    noqa = False
+
     def __init__(self, filename, options, lines=None):
         """Initialice our file processor.
 
@@ -85,8 +88,6 @@ class FileProcessor(object):
         self.max_doc_length = options.max_doc_length
         #: Whether the current physical line is multiline
         self.multiline = False
-        #: Whether or not we're observing NoQA
-        self.noqa = False
         #: Previous level of indentation
         self.previous_indent_level = 0
         #: Previous logical line
@@ -171,7 +172,6 @@ class FileProcessor(object):
                 self.previous_unindented_logical_line = self.logical_line
         self.blank_lines = 0
         self.tokens = []
-        self.noqa = False
 
     def build_logical_line_tokens(self):
         """Build the mapping, comments, and logical line lists."""
@@ -216,8 +216,6 @@ class FileProcessor(object):
         comments, logical, mapping_list = self.build_logical_line_tokens()
         joined_comments = "".join(comments)
         self.logical_line = "".join(logical)
-        if defaults.NOQA_INLINE_REGEXP.search(joined_comments):
-            self.noqa = True
         self.statistics["logical lines"] += 1
         return joined_comments, self.logical_line, mapping_list
 

tests/integration/test_main.py

@@ -128,6 +128,18 @@ def test_bug_report_successful(capsys):
     assert err == ''
 
 
+def test_specific_noqa_does_not_clobber_pycodestyle_noqa(tmpdir, capsys):
+    """See https://gitlab.com/pycqa/flake8/issues/552."""
+    with tmpdir.as_cwd():
+        tmpdir.join('t.py').write("test = ('ABC' == None)  # noqa: E501\n")
+        _call_main(['t.py'], retv=1)
+
+    out, err = capsys.readouterr()
+    assert out == '''\
+t.py:1:15: E711 comparison to None should be 'if cond is None:'
+'''
+
+
 def test_obtaining_args_from_sys_argv_when_not_explicity_provided(capsys):
     """Test that arguments are obtained from 'sys.argv'."""
     with mock.patch('sys.argv', ['flake8', '--help']):