Improved convention flag as per #128

Author: Nurdok

docs/snippets/cli.rst

@@ -18,8 +18,7 @@ Usage
                             which errors to ignore (with a list of comma-separated
                             error codes). for example: --ignore=D101,D202
       --convention=<name>   choose the basic list of checked errors by specifying
-                            an existing convention. for example:
-                            --convention=pep257
+                            an existing convention. Possible conventions: pep257
       --add-select=<codes>  amend the list of errors to check for by specifying
                             more error codes to check.
       --add-ignore=<codes>  amend the list of errors to check for by specifying
@@ -36,6 +35,7 @@ Usage
       -v, --verbose         print status information
       --count               print total number of errors to stdout
 
+
 Return Code
 ^^^^^^^^^^^
 

pep257.py

@@ -626,8 +626,14 @@ def to_rst(cls):
                                  '"signature"')
 
 
-class Conventions(object):
-    pep257 = set(ErrorRegistry.get_error_codes())
+class AttrDict(dict):
+    def __getattr__(self, item):
+        return self[item]
+
+
+conventions = AttrDict({
+    'pep257': set(ErrorRegistry.get_error_codes()),
+})
 
 
 def get_option_parser():
@@ -651,7 +657,8 @@ def get_option_parser():
                 'codes). for example: --ignore=D101,D202')
     option('--convention', metavar='<name>', default='',
            help='choose the basic list of checked errors by specifying an '
-                'existing convention. for example: --convention=pep257')
+                'existing convention. Possible conventions: {0}'
+                .format(', '.join(conventions)))
     option('--add-select', metavar='<codes>', default='',
            help='amend the list of errors to check for by specifying more '
                 'error codes to check.')
@@ -716,7 +723,7 @@ def check(filenames, select=None, ignore=None):
         checked_codes = (select or
                          set(ErrorRegistry.get_error_codes()) - set(ignore))
     else:
-        checked_codes = Conventions.pep257
+        checked_codes = conventions.pep257
 
     for filename in filenames:
         log.info('Checking file %s.', filename)
@@ -811,9 +818,9 @@ def get_checked_error_codes(options):
     elif options.select:
         checked_codes = set(options.select.split(','))
     elif options.convention:
-        checked_codes = getattr(Conventions, options.convention)
+        checked_codes = getattr(conventions, options.convention)
     else:
-        checked_codes = Conventions.pep257
+        checked_codes = conventions.pep257
     checked_codes -= set(options.add_ignore.split(','))
     checked_codes |= set(options.add_select.split(','))
     return checked_codes - set('')
@@ -826,7 +833,9 @@ def validate_options(options):
             log.error('Cannot pass both {0} and {1}. They are '
                       'mutually exclusive.'.format(opt1, opt2))
             return False
-    if options.convention and not hasattr(Conventions, options.convention):
+    if options.convention and options.convention not in conventions:
+        log.error("Illegal convention '{0}'. Possible conventions: {1}"
+                  .format(options.convention, ', '.join(conventions.keys())))
         return False
     return True
 

test_pep257.py

@@ -289,3 +289,11 @@ def test_missing_docstring_in_package():
         assert code == 1
         assert 'D100' not in err  # shouldn't be treated as a module
         assert 'D104' in err  # missing docstring in package
+
+
+def test_illegal_convention():
+    with Pep257Env() as env:
+        out, err, code = env.invoke_pep257('--convention=illegal_conv')
+        assert code == 2
+        assert "Illegal convention 'illegal_conv'." in err
+        assert 'Possible conventions: pep257' in err