Add default formatting class

flake8/formatting/default.py

@@ -0,0 +1,32 @@
+"""Default formatting class for Flake8."""
+from flake8.formatting import base
+
+
+class Default(base.BaseFormatter):
+    """Default formatter for Flake8.
+
+    This also handles backwards compatibility for people specifying a custom
+    format string.
+    """
+
+    error_format = '%(path)s:%(row)d:%(col)d: %(code)s %(text)s'
+
+    def after_init(self):
+        """Check for a custom format string."""
+        self.output_fd = None
+        if self.options.format.lower() != 'default':
+            self.error_format = self.options.format
+
+    def format(self, error):
+        """Format and write error out.
+
+        If an output filename is specified, write formatted errors to that
+        file. Otherwise, print the formatted error to standard out.
+        """
+        return self.error_format % {
+            "code": error.code,
+            "text": error.text,
+            "path": error.filename,
+            "row": error.line_number,
+            "col": error.column_number,
+        }

flake8/main/cli.py

@@ -54,7 +54,7 @@ def register_default_options(option_manager):
     # TODO(sigmavirus24): Figure out --first/--repeat
 
     add_option(
-        '--format', metavar='format', default='default', choices=['default'],
+        '--format', metavar='format', default='default',
         parse_from_config=True,
         help='Format errors according to the chosen formatter.',
     )

setup.py

@@ -70,6 +70,9 @@ setuptools.setup(
         'flake8.extension': [
             'F = flake8.plugins.pyflakes:FlakesChecker',
         ],
+        'flake8.format': [
+            'default = flake8.formatting.default.Default',
+        ],
     },
     classifiers=[
         "Environment :: Console",