| # Copyright (c) 2009-2010 Arista Networks, Inc. - James Lingard |
| # Copyright (c) 2004-2010 LOGILAB S.A. (Paris, FRANCE). |
| # http://www.logilab.fr/ -- mailto:contact@logilab.fr |
| # This program is free software; you can redistribute it and/or modify it under |
| # the terms of the GNU General Public License as published by the Free Software |
| # Foundation; either version 2 of the License, or (at your option) any later |
| # version. |
| # |
| # This program is distributed in the hope that it will be useful, but WITHOUT |
| # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details |
| # |
| # You should have received a copy of the GNU General Public License along with |
| # this program; if not, write to the Free Software Foundation, Inc., |
| # 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| |
| |
| """Checker for string formatting operations. |
| """ |
| |
| import string |
| from logilab import astng |
| from pylint.interfaces import IASTNGChecker |
| from pylint.checkers import BaseChecker |
| from pylint.checkers import utils |
| |
| |
| MSGS = { |
| 'E1300': ("Unsupported format character %r (%#02x) at index %d", |
| "Used when a unsupported format character is used in a format\ |
| string."), |
| 'E1301': ("Format string ends in middle of conversion specifier", |
| "Used when a format string terminates before the end of a \ |
| conversion specifier."), |
| 'E1302': ("Mixing named and unnamed conversion specifiers in format string", |
| "Used when a format string contains both named (e.g. '%(foo)d') \ |
| and unnamed (e.g. '%d') conversion specifiers. This is also \ |
| used when a named conversion specifier contains * for the \ |
| minimum field width and/or precision."), |
| 'E1303': ("Expected mapping for format string, not %s", |
| "Used when a format string that uses named conversion specifiers \ |
| is used with an argument that is not a mapping."), |
| 'W1300': ("Format string dictionary key should be a string, not %s", |
| "Used when a format string that uses named conversion specifiers \ |
| is used with a dictionary whose keys are not all strings."), |
| 'W1301': ("Unused key %r in format string dictionary", |
| "Used when a format string that uses named conversion specifiers \ |
| is used with a dictionary that conWtains keys not required by the \ |
| format string."), |
| 'E1304': ("Missing key %r in format string dictionary", |
| "Used when a format string that uses named conversion specifiers \ |
| is used with a dictionary that doesn't contain all the keys \ |
| required by the format string."), |
| 'E1305': ("Too many arguments for format string", |
| "Used when a format string that uses unnamed conversion \ |
| specifiers is given too few arguments."), |
| 'E1306': ("Not enough arguments for format string", |
| "Used when a format string that uses unnamed conversion \ |
| specifiers is given too many arguments"), |
| } |
| |
| OTHER_NODES = (astng.Const, astng.List, astng.Backquote, |
| astng.Lambda, astng.Function, |
| astng.ListComp, astng.SetComp, astng.GenExpr) |
| |
| class StringFormatChecker(BaseChecker): |
| """Checks string formatting operations to ensure that the format string |
| is valid and the arguments match the format string. |
| """ |
| |
| __implements__ = (IASTNGChecker,) |
| name = 'string_format' |
| msgs = MSGS |
| |
| def visit_binop(self, node): |
| if node.op != '%': |
| return |
| left = node.left |
| args = node.right |
| |
| if not (isinstance(left, astng.Const) |
| and isinstance(left.value, basestring)): |
| return |
| format_string = left.value |
| try: |
| required_keys, required_num_args = \ |
| utils.parse_format_string(format_string) |
| except utils.UnsupportedFormatCharacter, e: |
| c = format_string[e.index] |
| self.add_message('E1300', node=node, args=(c, ord(c), e.index)) |
| return |
| except utils.IncompleteFormatString: |
| self.add_message('E1301', node=node) |
| return |
| if required_keys and required_num_args: |
| # The format string uses both named and unnamed format |
| # specifiers. |
| self.add_message('E1302', node=node) |
| elif required_keys: |
| # The format string uses only named format specifiers. |
| # Check that the RHS of the % operator is a mapping object |
| # that contains precisely the set of keys required by the |
| # format string. |
| if isinstance(args, astng.Dict): |
| keys = set() |
| unknown_keys = False |
| for k, v in args.items: |
| if isinstance(k, astng.Const): |
| key = k.value |
| if isinstance(key, basestring): |
| keys.add(key) |
| else: |
| self.add_message('W1300', node=node, args=key) |
| else: |
| # One of the keys was something other than a |
| # constant. Since we can't tell what it is, |
| # supress checks for missing keys in the |
| # dictionary. |
| unknown_keys = True |
| if not unknown_keys: |
| for key in required_keys: |
| if key not in keys: |
| self.add_message('E1304', node=node, args=key) |
| for key in keys: |
| if key not in required_keys: |
| self.add_message('W1301', node=node, args=key) |
| elif isinstance(args, OTHER_NODES + (astng.Tuple,)): |
| type_name = type(args).__name__ |
| self.add_message('E1303', node=node, args=type_name) |
| # else: |
| # The RHS of the format specifier is a name or |
| # expression. It may be a mapping object, so |
| # there's nothing we can check. |
| else: |
| # The format string uses only unnamed format specifiers. |
| # Check that the number of arguments passed to the RHS of |
| # the % operator matches the number required by the format |
| # string. |
| if isinstance(args, astng.Tuple): |
| num_args = len(args.elts) |
| elif isinstance(args, OTHER_NODES + (astng.Dict, astng.DictComp)): |
| num_args = 1 |
| else: |
| # The RHS of the format specifier is a name or |
| # expression. It could be a tuple of unknown size, so |
| # there's nothing we can check. |
| num_args = None |
| if num_args is not None: |
| if num_args > required_num_args: |
| self.add_message('E1305', node=node) |
| elif num_args < required_num_args: |
| self.add_message('E1306', node=node) |
| |
| |
| def register(linter): |
| """required method to auto register this checker """ |
| linter.register_checker(StringFormatChecker(linter)) |
