# -*- coding: utf-8 -*- # django-lint -- Static analysis tool for Django projects and applications # Copyright (C) 2008-2009 Chris Lamb # # 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 3 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, see . from logilab import astng from pylint.interfaces import IASTNGChecker from pylint.checkers import BaseChecker from pylint.checkers.utils import safe_infer from utils import is_model class ModelFieldsChecker(BaseChecker): __implements__ = IASTNGChecker name = 'django_model_fields' msgs = { 'W6000': ('%s: Nullable CharField or TextField', ''), 'W6001': ( "%s: Naive tree structure implementation using ForeignKey('self')", ''), 'W6002': ( 'Model has too many fields (%d/%d); consider splitting model', ''), 'W6003': ('Model has no fields', ''), 'W6004': ('%s: Field is nullable but blank=False', ''), 'W6005': ('%s: uses brittle unique_for_%s', ''), 'W6006': ('%s: ForeignKey missing related_name', ''), 'W6007': ( '%s: CharField with huge (%d/%d) max_length instead of TextField', ''), 'W6008': ('%s: Uses superceded auto_now or auto_now_add', ''), 'W6009': ( '%s: NullBooleanField instead of BooleanField with null=True', ''), 'W6010': ('%s: %s has database-dependent limits', ''), 'W6011': ('%s: URLField uses verify_exists=True default', ''), 'W6012': ( '%s: BooleanField with default=True will not be reflected in database', ''), 'W6013': ( '%s: Unique ForeignKey constraint better modelled as OneToOneField', ''), 'W6014': ('%s: primary_key=True should imply unique=True', ''), 'W6015': ('%s: %s=False is implicit', ''), 'W6016': ('%s: Nullable ManyToManyField makes no sense', ''), } options = ( ('max-model-fields', { 'default': 20, 'type': 'int', 'metavar': '', 'help': 'Maximum number of fields for a model', }), ('max-charfield-length', { 'default': 512, 'type': 'int', 'metavar': '', 'help': 'Maximum size of max_length on a CharField', }), ) def visit_module(self, node): self.field_count = 0 def leave_class(self, node): if not is_model(node): return if is_model(node, check_base_classes=False) and self.field_count == 0: self.add_message('W6003', node=node) elif self.field_count > self.config.max_model_fields: self.add_message('W6002', node=node, args=(self.field_count, self.config.max_model_fields)) self.field_count = 0 def visit_callfunc(self, node): if not is_model(node.frame()): # We only care about fields attached to models return val = safe_infer(node) if not val or not val.root().name.startswith('django.db.models.fields'): # Not a field return assname = '(unknown name)' x = node.parent.get_children().next() if isinstance(x, astng.AssName): assname = x.name self.field_count += 1 # Parse kwargs options = dict([(option, None) for option in ( 'null', 'blank', 'unique', 'default', 'auto_now', 'primary_key', 'auto_now_add', 'verify_exists', 'related_name', 'max_length', 'unique_for_date', 'unique_for_month', 'unique_for_year', )]) for arg in node.args: if not isinstance(arg, astng.Keyword): continue for option in options.keys(): if arg.arg == option: try: options[option] = safe_infer(arg.value).value except AttributeError: # Don't lint this field if we cannot infer everything return if not val.name.lower().startswith('null'): for option in ('null', 'blank'): if options[option] is False: self.add_message('W6015', node=node, args=(assname, option,)) # Field type specific checks if val.name in ('CharField', 'TextField'): if options['null']: self.add_message('W6000', node=node, args=(assname,)) if val.name == 'CharField' and \ options['max_length'] > self.config.max_charfield_length: self.add_message('W6007', node=node, args=( assname, options['max_length'], self.config.max_charfield_length, )) elif val.name == 'BooleanField': if options['default']: self.add_message('W6012', node=node, args=(assname,)) elif val.name == 'ForeignKey': val = safe_infer(node.args[0]) if isinstance(val, astng.Const) and val.value == 'self': self.add_message('W6001', node=node, args=(assname,)) elif not options['related_name']: self.add_message('W6006', node=node, args=(assname,)) if options['primary_key'] and options['unique'] is False: self.add_message('W6014', node=node, args=(assname,)) elif options['primary_key'] or options['unique']: self.add_message('W6013', node=node, args=(assname,)) elif val.name == 'URLField': if options['verify_exists'] is None: self.add_message('W6011', node=node, args=(assname,)) elif val.name in ('PositiveSmallIntegerField', 'SmallIntegerField'): self.add_message('W6010', node=node, args=(assname, val.name)) elif val.name == 'NullBooleanField': self.add_message('W6009', node=node, args=(assname,)) elif val.name == 'ManyToManyField': if options['null']: self.add_message('W6016', node=node, args=(assname,)) # Generic checks if options['null'] and not options['blank']: self.add_message('W6004', node=node, args=(assname,)) if options['auto_now'] or options['auto_now_add']: self.add_message('W6008', node=node, args=(assname,)) for suffix in ('date', 'month', 'year'): if options['unique_for_%s' % suffix]: self.add_message('W6005', node=node, args=(assname, suffix))