Noissue - Fix E305 by adapting flake8-abp to use groups, run tests on Python 3.6

flake8-abp/flake8_abp.py

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 import ast
 import re
 import tokenize
 import sys
 import collections
 
 try:
     import builtins
 except ImportError:
     import __builtin__ as builtins
 
 import pkg_resources
+import flake8
 
 try:
     ascii
 except NameError:
     ascii = repr
 
 __version__ = pkg_resources.get_distribution('flake8-abp').version
 
 DISCOURAGED_APIS = {
     're.match': 're.search',
@@ skipping 309 matching lines @@
             keys.append(key)
 
     def visit_Dict(self, node):
         self._visit_hash_keys(node.keys, 'key in dict')
 
     def visit_Set(self, node):
         self._visit_hash_keys(node.elts, 'item in set')
 
 
 class ASTChecker(object):
-    name = 'abp'
-    version = __version__
-
     def __init__(self, tree, filename):
         self.tree = tree
 
     def run(self):
         visitor = TreeVisitor()
         visitor.visit(self.tree)
 
         for node, error in visitor.errors:
             yield (node.lineno, node.col_offset, error, type(self))
 
 
 def check_non_default_encoding(physical_line, line_number):
     if line_number <= 2 and re.search(r'^\s*#.*coding[:=]', physical_line):
         return (0, 'A303 non-default file encoding')
 
-check_non_default_encoding.name = 'abp-non-default-encoding'

[Sebastian Noack, 2017/01/12 15:55:03]

With flake8 3.2.0, it begun to use pycodestyle 2.2.0, introducing an E305 here,
since according to PEP-8 there should be two blank lines below the function
definition. Arguably this doesn't make much sense if the code below assigns
metadata to the same function.

However, it turned out that if we group our checkers together (by using a common
prefix separated by a dot, when registering the entry points in setup.py),
flake8 is using that prefix as name and the __version__ variable of this module,
while the attributes on the individual checkers are obsolete.

Unfortunately, this requires flake8 3, and we are still stuck with flake8 2 for
sitescripts, buildtools and cms where we also use flake8-putty. But we can
basically archive the same for flake8 2, by assigning the same name and version
in a loop, see below.

-check_non_default_encoding.version = __version__
-
 
 def check_quotes(logical_line, tokens, previous_logical, checker_state):
     first_token = True
 
     token_strings = [t[1] for t in tokens]
     future_import = token_strings[:3] == ['from', '__future__', 'import']
 
     if future_import and 'unicode_literals' in token_strings:
         checker_state['has_unicode_literals'] = True
 
@@ skipping 32 matching lines @@
                     if 'u' in prefixes or u_literals and 'b' not in prefixes:
                         prefix = 'u'
 
                 literal = '{0}{1}{2}{1}'.format(prefix, quote, text)
                 if ascii(eval(literal)) != literal:
                     yield (start, "A110 string literal doesn't match "
                                   '{}()'.format(ascii.__name__))
 
         first_token = False
 
-check_quotes.name = 'abp-quotes'
-check_quotes.version = __version__
-
 
 def check_redundant_parenthesis(logical_line, tokens):
     start_line = tokens[0][2][0]
     level = 0
     statement = None
 
     for i, (kind, token, _, end, _) in enumerate(tokens):
         if kind == tokenize.INDENT or kind == tokenize.DEDENT:
             continue
 
@@ skipping 31 matching lines @@
                 if level == 0:
                     # outer parenthesis closed before end of expression
                     if tokens[i + 1][:2] != (tokenize.OP, ':'):
                         break
 
                     return [(pos, 'A111 redundant parenthesis for {} '
                                   'statement'.format(statement))]
 
     return []
 
-check_redundant_parenthesis.name = 'abp-redundant-parenthesis'
-check_redundant_parenthesis.version = __version__
+
+# With flake8 3, the way the entry points are register in setup.py,
+# they are recognized as a group, and the name and version is detected
+# automatically. For compatibility with flake8 2, however, we need to
+# assign the name and version to each checker individually.
+if int(flake8.__version__.split('.')[0]) < 3:

[Sebastian Noack, 2017/01/12 15:55:03]

We could theoretically skip this check and assign the name and version no matter
what. However, this way it's 1. more obvious that this is a backwards
compatibility hack, 2. we make sure that the new mechanism (i.e. groups) is
already used (and tested) when using flake8 3.

[Vasily Kuznetsov, 2017/01/12 16:08:51]

Acknowledged.

+    for checker in [ASTChecker, check_non_default_encoding,
+                    check_quotes, check_redundant_parenthesis]:
+        checker.name = 'abp'
+        checker.version = __version__