Skip filename pattern check for provided files

By default, when discovering files for users, we use the filename
patterns to determine whether or not we should check that file. However,
when a user provides the path to a file, we should instead skip checking
the name against the filename patterns provided.

For example, in Flake8 2.6 this worked:

    $ flake8 bin/script.py
    $ flake8 bin/script

But prior to this commit only

    $ flake8 bin/script.py

works. This commit will skip the filename pattern check if the user
provides the path explicitly which allows

    $ flake8 bin/script

to work again as expected.

Closes #266

1 files changed, 8 insertions, 1 deletions

diff --git a/src/flake8/checker.py b/src/flake8/checker.py
index b4e22b2..cf25117 100644
--- a/src/flake8/checker.py
+++ b/src/flake8/checker.py
@@ -275,7 +275,14 @@ class Manager(object):
             for argument in paths
             for filename in utils.filenames_from(argument,
                                                  self.is_path_excluded)
-            if should_create_file_checker(filename)
+            # NOTE(sigmavirus24): If a user explicitly specifies something,
+            # e.g, ``flake8 bin/script`` then we should run Flake8 against
+            # that. Since should_create_file_checker looks to see if the
+            # filename patterns match the filename, we want to skip that in
+            # the event that the argument and the filename are identical.
+            # If it was specified explicitly, the user intended for it to be
+            # checked.
+            if argument == filename or should_create_file_checker(filename)
         ]
         LOG.info('Checking %d files', len(self.checkers))