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| 1 # Copyright (c) 2003-2014 LOGILAB S.A. (Paris, FRANCE). |
| 2 # http://www.logilab.fr/ -- mailto:contact@logilab.fr |
| 3 # |
| 4 # This program is free software; you can redistribute it and/or modify it under |
| 5 # the terms of the GNU General Public License as published by the Free Software |
| 6 # Foundation; either version 2 of the License, or (at your option) any later |
| 7 # version. |
| 8 # |
| 9 # This program is distributed in the hope that it will be useful, but WITHOUT |
| 10 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| 11 # FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
| 12 # |
| 13 # You should have received a copy of the GNU General Public License along with |
| 14 # this program; if not, write to the Free Software Foundation, Inc., |
| 15 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. |
| 16 """classes checker for Python code |
| 17 """ |
| 18 from __future__ import generators |
| 19 |
| 20 import sys |
| 21 from collections import defaultdict |
| 22 |
| 23 import astroid |
| 24 from astroid import YES, Instance, are_exclusive, AssAttr, Class |
| 25 from astroid.bases import Generator, BUILTINS |
| 26 from astroid.inference import InferenceContext |
| 27 |
| 28 from pylint.interfaces import IAstroidChecker |
| 29 from pylint.checkers import BaseChecker |
| 30 from pylint.checkers.utils import ( |
| 31 PYMETHODS, overrides_a_method, check_messages, is_attr_private, |
| 32 is_attr_protected, node_frame_class, safe_infer, is_builtin_object, |
| 33 decorated_with_property, unimplemented_abstract_methods) |
| 34 import six |
| 35 |
| 36 if sys.version_info >= (3, 0): |
| 37 NEXT_METHOD = '__next__' |
| 38 else: |
| 39 NEXT_METHOD = 'next' |
| 40 ITER_METHODS = ('__iter__', '__getitem__') |
| 41 |
| 42 def _called_in_methods(func, klass, methods): |
| 43 """ Check if the func was called in any of the given methods, |
| 44 belonging to the *klass*. Returns True if so, False otherwise. |
| 45 """ |
| 46 if not isinstance(func, astroid.Function): |
| 47 return False |
| 48 for method in methods: |
| 49 try: |
| 50 infered = klass.getattr(method) |
| 51 except astroid.NotFoundError: |
| 52 continue |
| 53 for infer_method in infered: |
| 54 for callfunc in infer_method.nodes_of_class(astroid.CallFunc): |
| 55 try: |
| 56 bound = next(callfunc.func.infer()) |
| 57 except (astroid.InferenceError, StopIteration): |
| 58 continue |
| 59 if not isinstance(bound, astroid.BoundMethod): |
| 60 continue |
| 61 func_obj = bound._proxied |
| 62 if isinstance(func_obj, astroid.UnboundMethod): |
| 63 func_obj = func_obj._proxied |
| 64 if func_obj.name == func.name: |
| 65 return True |
| 66 return False |
| 67 |
| 68 def class_is_abstract(node): |
| 69 """return true if the given class node should be considered as an abstract |
| 70 class |
| 71 """ |
| 72 for method in node.methods(): |
| 73 if method.parent.frame() is node: |
| 74 if method.is_abstract(pass_is_abstract=False): |
| 75 return True |
| 76 return False |
| 77 |
| 78 def _is_attribute_property(name, klass): |
| 79 """ Check if the given attribute *name* is a property |
| 80 in the given *klass*. |
| 81 |
| 82 It will look for `property` calls or for functions |
| 83 with the given name, decorated by `property` or `property` |
| 84 subclasses. |
| 85 Returns ``True`` if the name is a property in the given klass, |
| 86 ``False`` otherwise. |
| 87 """ |
| 88 |
| 89 try: |
| 90 attributes = klass.getattr(name) |
| 91 except astroid.NotFoundError: |
| 92 return False |
| 93 property_name = "{0}.property".format(BUILTINS) |
| 94 for attr in attributes: |
| 95 try: |
| 96 infered = next(attr.infer()) |
| 97 except astroid.InferenceError: |
| 98 continue |
| 99 if (isinstance(infered, astroid.Function) and |
| 100 decorated_with_property(infered)): |
| 101 return True |
| 102 if infered.pytype() == property_name: |
| 103 return True |
| 104 return False |
| 105 |
| 106 |
| 107 MSGS = { |
| 108 'F0202': ('Unable to check methods signature (%s / %s)', |
| 109 'method-check-failed', |
| 110 'Used when Pylint has been unable to check methods signature \ |
| 111 compatibility for an unexpected reason. Please report this kind \ |
| 112 if you don\'t make sense of it.'), |
| 113 |
| 114 'E0202': ('An attribute defined in %s line %s hides this method', |
| 115 'method-hidden', |
| 116 'Used when a class defines a method which is hidden by an ' |
| 117 'instance attribute from an ancestor class or set by some ' |
| 118 'client code.'), |
| 119 'E0203': ('Access to member %r before its definition line %s', |
| 120 'access-member-before-definition', |
| 121 'Used when an instance member is accessed before it\'s actually\ |
| 122 assigned.'), |
| 123 'W0201': ('Attribute %r defined outside __init__', |
| 124 'attribute-defined-outside-init', |
| 125 'Used when an instance attribute is defined outside the __init__\ |
| 126 method.'), |
| 127 |
| 128 'W0212': ('Access to a protected member %s of a client class', # E0214 |
| 129 'protected-access', |
| 130 'Used when a protected member (i.e. class member with a name \ |
| 131 beginning with an underscore) is access outside the class or a \ |
| 132 descendant of the class where it\'s defined.'), |
| 133 |
| 134 'E0211': ('Method has no argument', |
| 135 'no-method-argument', |
| 136 'Used when a method which should have the bound instance as \ |
| 137 first argument has no argument defined.'), |
| 138 'E0213': ('Method should have "self" as first argument', |
| 139 'no-self-argument', |
| 140 'Used when a method has an attribute different the "self" as\ |
| 141 first argument. This is considered as an error since this is\ |
| 142 a so common convention that you shouldn\'t break it!'), |
| 143 'C0202': ('Class method %s should have %s as first argument', # E0212 |
| 144 'bad-classmethod-argument', |
| 145 'Used when a class method has a first argument named differently ' |
| 146 'than the value specified in valid-classmethod-first-arg option ' |
| 147 '(default to "cls"), recommended to easily differentiate them ' |
| 148 'from regular instance methods.'), |
| 149 'C0203': ('Metaclass method %s should have %s as first argument', # E0214 |
| 150 'bad-mcs-method-argument', |
| 151 'Used when a metaclass method has a first agument named ' |
| 152 'differently than the value specified in valid-classmethod-first' |
| 153 '-arg option (default to "cls"), recommended to easily ' |
| 154 'differentiate them from regular instance methods.'), |
| 155 'C0204': ('Metaclass class method %s should have %s as first argument', |
| 156 'bad-mcs-classmethod-argument', |
| 157 'Used when a metaclass class method has a first argument named ' |
| 158 'differently than the value specified in valid-metaclass-' |
| 159 'classmethod-first-arg option (default to "mcs"), recommended to ' |
| 160 'easily differentiate them from regular instance methods.'), |
| 161 |
| 162 'W0211': ('Static method with %r as first argument', |
| 163 'bad-staticmethod-argument', |
| 164 'Used when a static method has "self" or a value specified in ' |
| 165 'valid-classmethod-first-arg option or ' |
| 166 'valid-metaclass-classmethod-first-arg option as first argument.' |
| 167 ), |
| 168 'R0201': ('Method could be a function', |
| 169 'no-self-use', |
| 170 'Used when a method doesn\'t use its bound instance, and so could\ |
| 171 be written as a function.' |
| 172 ), |
| 173 |
| 174 'E0221': ('Interface resolved to %s is not a class', |
| 175 'interface-is-not-class', |
| 176 'Used when a class claims to implement an interface which is not \ |
| 177 a class.'), |
| 178 'E0222': ('Missing method %r from %s interface', |
| 179 'missing-interface-method', |
| 180 'Used when a method declared in an interface is missing from a \ |
| 181 class implementing this interface'), |
| 182 'W0221': ('Arguments number differs from %s %r method', |
| 183 'arguments-differ', |
| 184 'Used when a method has a different number of arguments than in \ |
| 185 the implemented interface or in an overridden method.'), |
| 186 'W0222': ('Signature differs from %s %r method', |
| 187 'signature-differs', |
| 188 'Used when a method signature is different than in the \ |
| 189 implemented interface or in an overridden method.'), |
| 190 'W0223': ('Method %r is abstract in class %r but is not overridden', |
| 191 'abstract-method', |
| 192 'Used when an abstract method (i.e. raise NotImplementedError) is
\ |
| 193 not overridden in concrete class.' |
| 194 ), |
| 195 'F0220': ('failed to resolve interfaces implemented by %s (%s)', # W0224 |
| 196 'unresolved-interface', |
| 197 'Used when a Pylint as failed to find interfaces implemented by \ |
| 198 a class'), |
| 199 |
| 200 |
| 201 'W0231': ('__init__ method from base class %r is not called', |
| 202 'super-init-not-called', |
| 203 'Used when an ancestor class method has an __init__ method \ |
| 204 which is not called by a derived class.'), |
| 205 'W0232': ('Class has no __init__ method', |
| 206 'no-init', |
| 207 'Used when a class has no __init__ method, neither its parent \ |
| 208 classes.'), |
| 209 'W0233': ('__init__ method from a non direct base class %r is called', |
| 210 'non-parent-init-called', |
| 211 'Used when an __init__ method is called on a class which is not \ |
| 212 in the direct ancestors for the analysed class.'), |
| 213 'W0234': ('__iter__ returns non-iterator', |
| 214 'non-iterator-returned', |
| 215 'Used when an __iter__ method returns something which is not an \ |
| 216 iterable (i.e. has no `%s` method)' % NEXT_METHOD), |
| 217 'E0235': ('__exit__ must accept 3 arguments: type, value, traceback', |
| 218 'bad-context-manager', |
| 219 'Used when the __exit__ special method, belonging to a \ |
| 220 context manager, does not accept 3 arguments \ |
| 221 (type, value, traceback).'), |
| 222 'E0236': ('Invalid object %r in __slots__, must contain ' |
| 223 'only non empty strings', |
| 224 'invalid-slots-object', |
| 225 'Used when an invalid (non-string) object occurs in __slots__.'), |
| 226 'E0237': ('Assigning to attribute %r not defined in class slots', |
| 227 'assigning-non-slot', |
| 228 'Used when assigning to an attribute not defined ' |
| 229 'in the class slots.'), |
| 230 'E0238': ('Invalid __slots__ object', |
| 231 'invalid-slots', |
| 232 'Used when an invalid __slots__ is found in class. ' |
| 233 'Only a string, an iterable or a sequence is permitted.'), |
| 234 'E0239': ('Inheriting %r, which is not a class.', |
| 235 'inherit-non-class', |
| 236 'Used when a class inherits from something which is not a ' |
| 237 'class.'), |
| 238 |
| 239 |
| 240 } |
| 241 |
| 242 |
| 243 class ClassChecker(BaseChecker): |
| 244 """checks for : |
| 245 * methods without self as first argument |
| 246 * overridden methods signature |
| 247 * access only to existent members via self |
| 248 * attributes not defined in the __init__ method |
| 249 * supported interfaces implementation |
| 250 * unreachable code |
| 251 """ |
| 252 |
| 253 __implements__ = (IAstroidChecker,) |
| 254 |
| 255 # configuration section name |
| 256 name = 'classes' |
| 257 # messages |
| 258 msgs = MSGS |
| 259 priority = -2 |
| 260 # configuration options |
| 261 options = (('ignore-iface-methods', |
| 262 {'default' : (#zope interface |
| 263 'isImplementedBy', 'deferred', 'extends', 'names', |
| 264 'namesAndDescriptions', 'queryDescriptionFor', 'getBases', |
| 265 'getDescriptionFor', 'getDoc', 'getName', 'getTaggedValue', |
| 266 'getTaggedValueTags', 'isEqualOrExtendedBy', 'setTaggedValue
', |
| 267 'isImplementedByInstancesOf', |
| 268 # twisted |
| 269 'adaptWith', |
| 270 # logilab.common interface |
| 271 'is_implemented_by'), |
| 272 'type' : 'csv', |
| 273 'metavar' : '<method names>', |
| 274 'help' : 'List of interface methods to ignore, \ |
| 275 separated by a comma. This is used for instance to not check methods defines \ |
| 276 in Zope\'s Interface base class.'} |
| 277 ), |
| 278 ('defining-attr-methods', |
| 279 {'default' : ('__init__', '__new__', 'setUp'), |
| 280 'type' : 'csv', |
| 281 'metavar' : '<method names>', |
| 282 'help' : 'List of method names used to declare (i.e. assign) \ |
| 283 instance attributes.'} |
| 284 ), |
| 285 ('valid-classmethod-first-arg', |
| 286 {'default' : ('cls',), |
| 287 'type' : 'csv', |
| 288 'metavar' : '<argument names>', |
| 289 'help' : 'List of valid names for the first argument in \ |
| 290 a class method.'} |
| 291 ), |
| 292 ('valid-metaclass-classmethod-first-arg', |
| 293 {'default' : ('mcs',), |
| 294 'type' : 'csv', |
| 295 'metavar' : '<argument names>', |
| 296 'help' : 'List of valid names for the first argument in \ |
| 297 a metaclass class method.'} |
| 298 ), |
| 299 ('exclude-protected', |
| 300 { |
| 301 'default': ( |
| 302 # namedtuple public API. |
| 303 '_asdict', '_fields', '_replace', '_source', '_make'), |
| 304 'type': 'csv', |
| 305 'metavar': '<protected access exclusions>', |
| 306 'help': ('List of member names, which should be excluded ' |
| 307 'from the protected access warning.')} |
| 308 )) |
| 309 |
| 310 def __init__(self, linter=None): |
| 311 BaseChecker.__init__(self, linter) |
| 312 self._accessed = [] |
| 313 self._first_attrs = [] |
| 314 self._meth_could_be_func = None |
| 315 |
| 316 def visit_class(self, node): |
| 317 """init visit variable _accessed and check interfaces |
| 318 """ |
| 319 self._accessed.append(defaultdict(list)) |
| 320 self._check_bases_classes(node) |
| 321 self._check_interfaces(node) |
| 322 # if not an interface, exception, metaclass |
| 323 if node.type == 'class': |
| 324 try: |
| 325 node.local_attr('__init__') |
| 326 except astroid.NotFoundError: |
| 327 self.add_message('no-init', args=node, node=node) |
| 328 self._check_slots(node) |
| 329 self._check_proper_bases(node) |
| 330 |
| 331 @check_messages('inherit-non-class') |
| 332 def _check_proper_bases(self, node): |
| 333 """ |
| 334 Detect that a class inherits something which is not |
| 335 a class or a type. |
| 336 """ |
| 337 for base in node.bases: |
| 338 ancestor = safe_infer(base) |
| 339 if ancestor in (YES, None): |
| 340 continue |
| 341 if (isinstance(ancestor, astroid.Instance) and |
| 342 ancestor.is_subtype_of('%s.type' % (BUILTINS,))): |
| 343 continue |
| 344 if not isinstance(ancestor, astroid.Class): |
| 345 self.add_message('inherit-non-class', |
| 346 args=base.as_string(), node=node) |
| 347 |
| 348 @check_messages('access-member-before-definition', |
| 349 'attribute-defined-outside-init') |
| 350 def leave_class(self, cnode): |
| 351 """close a class node: |
| 352 check that instance attributes are defined in __init__ and check |
| 353 access to existent members |
| 354 """ |
| 355 # check access to existent members on non metaclass classes |
| 356 accessed = self._accessed.pop() |
| 357 if cnode.type != 'metaclass': |
| 358 self._check_accessed_members(cnode, accessed) |
| 359 # checks attributes are defined in an allowed method such as __init__ |
| 360 if not self.linter.is_message_enabled('attribute-defined-outside-init'): |
| 361 return |
| 362 defining_methods = self.config.defining_attr_methods |
| 363 current_module = cnode.root() |
| 364 for attr, nodes in six.iteritems(cnode.instance_attrs): |
| 365 # skip nodes which are not in the current module and it may screw up |
| 366 # the output, while it's not worth it |
| 367 nodes = [n for n in nodes if not |
| 368 isinstance(n.statement(), (astroid.Delete, astroid.AugAssig
n)) |
| 369 and n.root() is current_module] |
| 370 if not nodes: |
| 371 continue # error detected by typechecking |
| 372 # check if any method attr is defined in is a defining method |
| 373 if any(node.frame().name in defining_methods |
| 374 for node in nodes): |
| 375 continue |
| 376 |
| 377 # check attribute is defined in a parent's __init__ |
| 378 for parent in cnode.instance_attr_ancestors(attr): |
| 379 attr_defined = False |
| 380 # check if any parent method attr is defined in is a defining me
thod |
| 381 for node in parent.instance_attrs[attr]: |
| 382 if node.frame().name in defining_methods: |
| 383 attr_defined = True |
| 384 if attr_defined: |
| 385 # we're done :) |
| 386 break |
| 387 else: |
| 388 # check attribute is defined as a class attribute |
| 389 try: |
| 390 cnode.local_attr(attr) |
| 391 except astroid.NotFoundError: |
| 392 for node in nodes: |
| 393 if node.frame().name not in defining_methods: |
| 394 # If the attribute was set by a callfunc in any |
| 395 # of the defining methods, then don't emit |
| 396 # the warning. |
| 397 if _called_in_methods(node.frame(), cnode, |
| 398 defining_methods): |
| 399 continue |
| 400 self.add_message('attribute-defined-outside-init', |
| 401 args=attr, node=node) |
| 402 |
| 403 def visit_function(self, node): |
| 404 """check method arguments, overriding""" |
| 405 # ignore actual functions |
| 406 if not node.is_method(): |
| 407 return |
| 408 klass = node.parent.frame() |
| 409 self._meth_could_be_func = True |
| 410 # check first argument is self if this is actually a method |
| 411 self._check_first_arg_for_type(node, klass.type == 'metaclass') |
| 412 if node.name == '__init__': |
| 413 self._check_init(node) |
| 414 return |
| 415 # check signature if the method overloads inherited method |
| 416 for overridden in klass.local_attr_ancestors(node.name): |
| 417 # get astroid for the searched method |
| 418 try: |
| 419 meth_node = overridden[node.name] |
| 420 except KeyError: |
| 421 # we have found the method but it's not in the local |
| 422 # dictionary. |
| 423 # This may happen with astroid build from living objects |
| 424 continue |
| 425 if not isinstance(meth_node, astroid.Function): |
| 426 continue |
| 427 self._check_signature(node, meth_node, 'overridden') |
| 428 break |
| 429 if node.decorators: |
| 430 for decorator in node.decorators.nodes: |
| 431 if isinstance(decorator, astroid.Getattr) and \ |
| 432 decorator.attrname in ('getter', 'setter', 'deleter'): |
| 433 # attribute affectation will call this method, not hiding it |
| 434 return |
| 435 if isinstance(decorator, astroid.Name) and decorator.name == 'pr
operty': |
| 436 # attribute affectation will either call a setter or raise |
| 437 # an attribute error, anyway not hiding the function |
| 438 return |
| 439 # check if the method is hidden by an attribute |
| 440 try: |
| 441 overridden = klass.instance_attr(node.name)[0] # XXX |
| 442 overridden_frame = overridden.frame() |
| 443 if (isinstance(overridden_frame, astroid.Function) |
| 444 and overridden_frame.type == 'method'): |
| 445 overridden_frame = overridden_frame.parent.frame() |
| 446 if (isinstance(overridden_frame, Class) |
| 447 and klass.is_subtype_of(overridden_frame.qname())): |
| 448 args = (overridden.root().name, overridden.fromlineno) |
| 449 self.add_message('method-hidden', args=args, node=node) |
| 450 except astroid.NotFoundError: |
| 451 pass |
| 452 |
| 453 # check non-iterators in __iter__ |
| 454 if node.name == '__iter__': |
| 455 self._check_iter(node) |
| 456 elif node.name == '__exit__': |
| 457 self._check_exit(node) |
| 458 |
| 459 def _check_slots(self, node): |
| 460 if '__slots__' not in node.locals: |
| 461 return |
| 462 for slots in node.igetattr('__slots__'): |
| 463 # check if __slots__ is a valid type |
| 464 for meth in ITER_METHODS: |
| 465 try: |
| 466 slots.getattr(meth) |
| 467 break |
| 468 except astroid.NotFoundError: |
| 469 continue |
| 470 else: |
| 471 self.add_message('invalid-slots', node=node) |
| 472 continue |
| 473 |
| 474 if isinstance(slots, astroid.Const): |
| 475 # a string, ignore the following checks |
| 476 continue |
| 477 if not hasattr(slots, 'itered'): |
| 478 # we can't obtain the values, maybe a .deque? |
| 479 continue |
| 480 |
| 481 if isinstance(slots, astroid.Dict): |
| 482 values = [item[0] for item in slots.items] |
| 483 else: |
| 484 values = slots.itered() |
| 485 if values is YES: |
| 486 return |
| 487 |
| 488 for elt in values: |
| 489 try: |
| 490 self._check_slots_elt(elt) |
| 491 except astroid.InferenceError: |
| 492 continue |
| 493 |
| 494 def _check_slots_elt(self, elt): |
| 495 for infered in elt.infer(): |
| 496 if infered is YES: |
| 497 continue |
| 498 if (not isinstance(infered, astroid.Const) or |
| 499 not isinstance(infered.value, six.string_types)): |
| 500 self.add_message('invalid-slots-object', |
| 501 args=infered.as_string(), |
| 502 node=elt) |
| 503 continue |
| 504 if not infered.value: |
| 505 self.add_message('invalid-slots-object', |
| 506 args=infered.as_string(), |
| 507 node=elt) |
| 508 |
| 509 def _check_iter(self, node): |
| 510 try: |
| 511 infered = node.infer_call_result(node) |
| 512 except astroid.InferenceError: |
| 513 return |
| 514 |
| 515 for infered_node in infered: |
| 516 if (infered_node is YES |
| 517 or isinstance(infered_node, Generator)): |
| 518 continue |
| 519 if isinstance(infered_node, astroid.Instance): |
| 520 try: |
| 521 infered_node.local_attr(NEXT_METHOD) |
| 522 except astroid.NotFoundError: |
| 523 self.add_message('non-iterator-returned', |
| 524 node=node) |
| 525 break |
| 526 |
| 527 def _check_exit(self, node): |
| 528 positional = sum(1 for arg in node.args.args if arg.name != 'self') |
| 529 if positional < 3 and not node.args.vararg: |
| 530 self.add_message('bad-context-manager', |
| 531 node=node) |
| 532 elif positional > 3: |
| 533 self.add_message('bad-context-manager', |
| 534 node=node) |
| 535 |
| 536 def leave_function(self, node): |
| 537 """on method node, check if this method couldn't be a function |
| 538 |
| 539 ignore class, static and abstract methods, initializer, |
| 540 methods overridden from a parent class and any |
| 541 kind of method defined in an interface for this warning |
| 542 """ |
| 543 if node.is_method(): |
| 544 if node.args.args is not None: |
| 545 self._first_attrs.pop() |
| 546 if not self.linter.is_message_enabled('no-self-use'): |
| 547 return |
| 548 class_node = node.parent.frame() |
| 549 if (self._meth_could_be_func and node.type == 'method' |
| 550 and not node.name in PYMETHODS |
| 551 and not (node.is_abstract() or |
| 552 overrides_a_method(class_node, node.name)) |
| 553 and class_node.type != 'interface'): |
| 554 self.add_message('no-self-use', node=node) |
| 555 |
| 556 def visit_getattr(self, node): |
| 557 """check if the getattr is an access to a class member |
| 558 if so, register it. Also check for access to protected |
| 559 class member from outside its class (but ignore __special__ |
| 560 methods) |
| 561 """ |
| 562 attrname = node.attrname |
| 563 # Check self |
| 564 if self.is_first_attr(node): |
| 565 self._accessed[-1][attrname].append(node) |
| 566 return |
| 567 if not self.linter.is_message_enabled('protected-access'): |
| 568 return |
| 569 |
| 570 self._check_protected_attribute_access(node) |
| 571 |
| 572 def visit_assattr(self, node): |
| 573 if isinstance(node.ass_type(), astroid.AugAssign) and self.is_first_attr
(node): |
| 574 self._accessed[-1][node.attrname].append(node) |
| 575 self._check_in_slots(node) |
| 576 |
| 577 def _check_in_slots(self, node): |
| 578 """ Check that the given assattr node |
| 579 is defined in the class slots. |
| 580 """ |
| 581 infered = safe_infer(node.expr) |
| 582 if infered and isinstance(infered, Instance): |
| 583 klass = infered._proxied |
| 584 if '__slots__' not in klass.locals or not klass.newstyle: |
| 585 return |
| 586 |
| 587 slots = klass.slots() |
| 588 if slots is None: |
| 589 return |
| 590 # If any ancestor doesn't use slots, the slots |
| 591 # defined for this class are superfluous. |
| 592 if any('__slots__' not in ancestor.locals and |
| 593 ancestor.name != 'object' |
| 594 for ancestor in klass.ancestors()): |
| 595 return |
| 596 |
| 597 if not any(slot.value == node.attrname for slot in slots): |
| 598 # If we have a '__dict__' in slots, then |
| 599 # assigning any name is valid. |
| 600 if not any(slot.value == '__dict__' for slot in slots): |
| 601 if _is_attribute_property(node.attrname, klass): |
| 602 # Properties circumvent the slots mechanism, |
| 603 # so we should not emit a warning for them. |
| 604 return |
| 605 self.add_message('assigning-non-slot', |
| 606 args=(node.attrname, ), node=node) |
| 607 |
| 608 @check_messages('protected-access') |
| 609 def visit_assign(self, assign_node): |
| 610 node = assign_node.targets[0] |
| 611 if not isinstance(node, AssAttr): |
| 612 return |
| 613 |
| 614 if self.is_first_attr(node): |
| 615 return |
| 616 |
| 617 self._check_protected_attribute_access(node) |
| 618 |
| 619 def _check_protected_attribute_access(self, node): |
| 620 '''Given an attribute access node (set or get), check if attribute |
| 621 access is legitimate. Call _check_first_attr with node before calling |
| 622 this method. Valid cases are: |
| 623 * self._attr in a method or cls._attr in a classmethod. Checked by |
| 624 _check_first_attr. |
| 625 * Klass._attr inside "Klass" class. |
| 626 * Klass2._attr inside "Klass" class when Klass2 is a base class of |
| 627 Klass. |
| 628 ''' |
| 629 attrname = node.attrname |
| 630 |
| 631 if (is_attr_protected(attrname) and |
| 632 attrname not in self.config.exclude_protected): |
| 633 |
| 634 klass = node_frame_class(node) |
| 635 |
| 636 # XXX infer to be more safe and less dirty ?? |
| 637 # in classes, check we are not getting a parent method |
| 638 # through the class object or through super |
| 639 callee = node.expr.as_string() |
| 640 |
| 641 # We are not in a class, no remaining valid case |
| 642 if klass is None: |
| 643 self.add_message('protected-access', node=node, args=attrname) |
| 644 return |
| 645 |
| 646 # If the expression begins with a call to super, that's ok. |
| 647 if isinstance(node.expr, astroid.CallFunc) and \ |
| 648 isinstance(node.expr.func, astroid.Name) and \ |
| 649 node.expr.func.name == 'super': |
| 650 return |
| 651 |
| 652 # We are in a class, one remaining valid cases, Klass._attr inside |
| 653 # Klass |
| 654 if not (callee == klass.name or callee in klass.basenames): |
| 655 # Detect property assignments in the body of the class. |
| 656 # This is acceptable: |
| 657 # |
| 658 # class A: |
| 659 # b = property(lambda: self._b) |
| 660 |
| 661 stmt = node.parent.statement() |
| 662 try: |
| 663 if (isinstance(stmt, astroid.Assign) and |
| 664 (stmt in klass.body or klass.parent_of(stmt)) and |
| 665 isinstance(stmt.value, astroid.CallFunc) and |
| 666 isinstance(stmt.value.func, astroid.Name) and |
| 667 stmt.value.func.name == 'property' and |
| 668 is_builtin_object(next(stmt.value.func.infer(), None
))): |
| 669 return |
| 670 except astroid.InferenceError: |
| 671 pass |
| 672 self.add_message('protected-access', node=node, args=attrname) |
| 673 |
| 674 def visit_name(self, node): |
| 675 """check if the name handle an access to a class member |
| 676 if so, register it |
| 677 """ |
| 678 if self._first_attrs and (node.name == self._first_attrs[-1] or |
| 679 not self._first_attrs[-1]): |
| 680 self._meth_could_be_func = False |
| 681 |
| 682 def _check_accessed_members(self, node, accessed): |
| 683 """check that accessed members are defined""" |
| 684 # XXX refactor, probably much simpler now that E0201 is in type checker |
| 685 for attr, nodes in six.iteritems(accessed): |
| 686 # deactivate "except doesn't do anything", that's expected |
| 687 # pylint: disable=W0704 |
| 688 try: |
| 689 # is it a class attribute ? |
| 690 node.local_attr(attr) |
| 691 # yes, stop here |
| 692 continue |
| 693 except astroid.NotFoundError: |
| 694 pass |
| 695 # is it an instance attribute of a parent class ? |
| 696 try: |
| 697 next(node.instance_attr_ancestors(attr)) |
| 698 # yes, stop here |
| 699 continue |
| 700 except StopIteration: |
| 701 pass |
| 702 # is it an instance attribute ? |
| 703 try: |
| 704 defstmts = node.instance_attr(attr) |
| 705 except astroid.NotFoundError: |
| 706 pass |
| 707 else: |
| 708 # filter out augment assignment nodes |
| 709 defstmts = [stmt for stmt in defstmts if stmt not in nodes] |
| 710 if not defstmts: |
| 711 # only augment assignment for this node, no-member should be |
| 712 # triggered by the typecheck checker |
| 713 continue |
| 714 # filter defstmts to only pick the first one when there are |
| 715 # several assignments in the same scope |
| 716 scope = defstmts[0].scope() |
| 717 defstmts = [stmt for i, stmt in enumerate(defstmts) |
| 718 if i == 0 or stmt.scope() is not scope] |
| 719 # if there are still more than one, don't attempt to be smarter |
| 720 # than we can be |
| 721 if len(defstmts) == 1: |
| 722 defstmt = defstmts[0] |
| 723 # check that if the node is accessed in the same method as |
| 724 # it's defined, it's accessed after the initial assignment |
| 725 frame = defstmt.frame() |
| 726 lno = defstmt.fromlineno |
| 727 for _node in nodes: |
| 728 if _node.frame() is frame and _node.fromlineno < lno \ |
| 729 and not are_exclusive(_node.statement(), defstmt, |
| 730 ('AttributeError', 'Exception',
'BaseException')): |
| 731 self.add_message('access-member-before-definition', |
| 732 node=_node, args=(attr, lno)) |
| 733 |
| 734 def _check_first_arg_for_type(self, node, metaclass=0): |
| 735 """check the name of first argument, expect: |
| 736 |
| 737 * 'self' for a regular method |
| 738 * 'cls' for a class method or a metaclass regular method (actually |
| 739 valid-classmethod-first-arg value) |
| 740 * 'mcs' for a metaclass class method (actually |
| 741 valid-metaclass-classmethod-first-arg) |
| 742 * not one of the above for a static method |
| 743 """ |
| 744 # don't care about functions with unknown argument (builtins) |
| 745 if node.args.args is None: |
| 746 return |
| 747 first_arg = node.args.args and node.argnames()[0] |
| 748 self._first_attrs.append(first_arg) |
| 749 first = self._first_attrs[-1] |
| 750 # static method |
| 751 if node.type == 'staticmethod': |
| 752 if (first_arg == 'self' or |
| 753 first_arg in self.config.valid_classmethod_first_arg or |
| 754 first_arg in self.config.valid_metaclass_classmethod_first_a
rg): |
| 755 self.add_message('bad-staticmethod-argument', args=first, node=n
ode) |
| 756 return |
| 757 self._first_attrs[-1] = None |
| 758 # class / regular method with no args |
| 759 elif not node.args.args: |
| 760 self.add_message('no-method-argument', node=node) |
| 761 # metaclass |
| 762 elif metaclass: |
| 763 # metaclass __new__ or classmethod |
| 764 if node.type == 'classmethod': |
| 765 self._check_first_arg_config( |
| 766 first, |
| 767 self.config.valid_metaclass_classmethod_first_arg, node, |
| 768 'bad-mcs-classmethod-argument', node.name) |
| 769 # metaclass regular method |
| 770 else: |
| 771 self._check_first_arg_config( |
| 772 first, |
| 773 self.config.valid_classmethod_first_arg, node, |
| 774 'bad-mcs-method-argument', |
| 775 node.name) |
| 776 # regular class |
| 777 else: |
| 778 # class method |
| 779 if node.type == 'classmethod': |
| 780 self._check_first_arg_config( |
| 781 first, |
| 782 self.config.valid_classmethod_first_arg, node, |
| 783 'bad-classmethod-argument', |
| 784 node.name) |
| 785 # regular method without self as argument |
| 786 elif first != 'self': |
| 787 self.add_message('no-self-argument', node=node) |
| 788 |
| 789 def _check_first_arg_config(self, first, config, node, message, |
| 790 method_name): |
| 791 if first not in config: |
| 792 if len(config) == 1: |
| 793 valid = repr(config[0]) |
| 794 else: |
| 795 valid = ', '.join(repr(v) for v in config[:-1]) |
| 796 valid = '%s or %r' % (valid, config[-1]) |
| 797 self.add_message(message, args=(method_name, valid), node=node) |
| 798 |
| 799 def _check_bases_classes(self, node): |
| 800 """check that the given class node implements abstract methods from |
| 801 base classes |
| 802 """ |
| 803 def is_abstract(method): |
| 804 return method.is_abstract(pass_is_abstract=False) |
| 805 |
| 806 # check if this class abstract |
| 807 if class_is_abstract(node): |
| 808 return |
| 809 |
| 810 methods = sorted( |
| 811 unimplemented_abstract_methods(node, is_abstract).items(), |
| 812 key=lambda item: item[0], |
| 813 ) |
| 814 for name, method in methods: |
| 815 owner = method.parent.frame() |
| 816 if owner is node: |
| 817 continue |
| 818 # owner is not this class, it must be a parent class |
| 819 # check that the ancestor's method is not abstract |
| 820 if name in node.locals: |
| 821 # it is redefined as an attribute or with a descriptor |
| 822 continue |
| 823 self.add_message('abstract-method', node=node, |
| 824 args=(name, owner.name)) |
| 825 |
| 826 def _check_interfaces(self, node): |
| 827 """check that the given class node really implements declared |
| 828 interfaces |
| 829 """ |
| 830 e0221_hack = [False] |
| 831 def iface_handler(obj): |
| 832 """filter interface objects, it should be classes""" |
| 833 if not isinstance(obj, astroid.Class): |
| 834 e0221_hack[0] = True |
| 835 self.add_message('interface-is-not-class', node=node, |
| 836 args=(obj.as_string(),)) |
| 837 return False |
| 838 return True |
| 839 ignore_iface_methods = self.config.ignore_iface_methods |
| 840 try: |
| 841 for iface in node.interfaces(handler_func=iface_handler): |
| 842 for imethod in iface.methods(): |
| 843 name = imethod.name |
| 844 if name.startswith('_') or name in ignore_iface_methods: |
| 845 # don't check method beginning with an underscore, |
| 846 # usually belonging to the interface implementation |
| 847 continue |
| 848 # get class method astroid |
| 849 try: |
| 850 method = node_method(node, name) |
| 851 except astroid.NotFoundError: |
| 852 self.add_message('missing-interface-method', |
| 853 args=(name, iface.name), |
| 854 node=node) |
| 855 continue |
| 856 # ignore inherited methods |
| 857 if method.parent.frame() is not node: |
| 858 continue |
| 859 # check signature |
| 860 self._check_signature(method, imethod, |
| 861 '%s interface' % iface.name) |
| 862 except astroid.InferenceError: |
| 863 if e0221_hack[0]: |
| 864 return |
| 865 implements = Instance(node).getattr('__implements__')[0] |
| 866 assignment = implements.parent |
| 867 assert isinstance(assignment, astroid.Assign) |
| 868 # assignment.expr can be a Name or a Tuple or whatever. |
| 869 # Use as_string() for the message |
| 870 # FIXME: in case of multiple interfaces, find which one could not |
| 871 # be resolved |
| 872 self.add_message('unresolved-interface', node=implements, |
| 873 args=(node.name, assignment.value.as_string())) |
| 874 |
| 875 def _check_init(self, node): |
| 876 """check that the __init__ method call super or ancestors'__init__ |
| 877 method |
| 878 """ |
| 879 if (not self.linter.is_message_enabled('super-init-not-called') and |
| 880 not self.linter.is_message_enabled('non-parent-init-called')): |
| 881 return |
| 882 klass_node = node.parent.frame() |
| 883 to_call = _ancestors_to_call(klass_node) |
| 884 not_called_yet = dict(to_call) |
| 885 for stmt in node.nodes_of_class(astroid.CallFunc): |
| 886 expr = stmt.func |
| 887 if not isinstance(expr, astroid.Getattr) \ |
| 888 or expr.attrname != '__init__': |
| 889 continue |
| 890 # skip the test if using super |
| 891 if isinstance(expr.expr, astroid.CallFunc) and \ |
| 892 isinstance(expr.expr.func, astroid.Name) and \ |
| 893 expr.expr.func.name == 'super': |
| 894 return |
| 895 try: |
| 896 klass = next(expr.expr.infer()) |
| 897 if klass is YES: |
| 898 continue |
| 899 # The infered klass can be super(), which was |
| 900 # assigned to a variable and the `__init__` was called later. |
| 901 # |
| 902 # base = super() |
| 903 # base.__init__(...) |
| 904 |
| 905 if (isinstance(klass, astroid.Instance) and |
| 906 isinstance(klass._proxied, astroid.Class) and |
| 907 is_builtin_object(klass._proxied) and |
| 908 klass._proxied.name == 'super'): |
| 909 return |
| 910 try: |
| 911 del not_called_yet[klass] |
| 912 except KeyError: |
| 913 if klass not in to_call: |
| 914 self.add_message('non-parent-init-called', |
| 915 node=expr, args=klass.name) |
| 916 except astroid.InferenceError: |
| 917 continue |
| 918 for klass, method in six.iteritems(not_called_yet): |
| 919 if klass.name == 'object' or method.parent.name == 'object': |
| 920 continue |
| 921 self.add_message('super-init-not-called', args=klass.name, node=node
) |
| 922 |
| 923 def _check_signature(self, method1, refmethod, class_type): |
| 924 """check that the signature of the two given methods match |
| 925 |
| 926 class_type is in 'class', 'interface' |
| 927 """ |
| 928 if not (isinstance(method1, astroid.Function) |
| 929 and isinstance(refmethod, astroid.Function)): |
| 930 self.add_message('method-check-failed', |
| 931 args=(method1, refmethod), node=method1) |
| 932 return |
| 933 # don't care about functions with unknown argument (builtins) |
| 934 if method1.args.args is None or refmethod.args.args is None: |
| 935 return |
| 936 # if we use *args, **kwargs, skip the below checks |
| 937 if method1.args.vararg or method1.args.kwarg: |
| 938 return |
| 939 if is_attr_private(method1.name): |
| 940 return |
| 941 if len(method1.args.args) != len(refmethod.args.args): |
| 942 self.add_message('arguments-differ', |
| 943 args=(class_type, method1.name), |
| 944 node=method1) |
| 945 elif len(method1.args.defaults) < len(refmethod.args.defaults): |
| 946 self.add_message('signature-differs', |
| 947 args=(class_type, method1.name), |
| 948 node=method1) |
| 949 |
| 950 def is_first_attr(self, node): |
| 951 """Check that attribute lookup name use first attribute variable name |
| 952 (self for method, cls for classmethod and mcs for metaclass). |
| 953 """ |
| 954 return self._first_attrs and isinstance(node.expr, astroid.Name) and \ |
| 955 node.expr.name == self._first_attrs[-1] |
| 956 |
| 957 def _ancestors_to_call(klass_node, method='__init__'): |
| 958 """return a dictionary where keys are the list of base classes providing |
| 959 the queried method, and so that should/may be called from the method node |
| 960 """ |
| 961 to_call = {} |
| 962 for base_node in klass_node.ancestors(recurs=False): |
| 963 try: |
| 964 to_call[base_node] = next(base_node.igetattr(method)) |
| 965 except astroid.InferenceError: |
| 966 continue |
| 967 return to_call |
| 968 |
| 969 |
| 970 def node_method(node, method_name): |
| 971 """get astroid for <method_name> on the given class node, ensuring it |
| 972 is a Function node |
| 973 """ |
| 974 for n in node.local_attr(method_name): |
| 975 if isinstance(n, astroid.Function): |
| 976 return n |
| 977 raise astroid.NotFoundError(method_name) |
| 978 |
| 979 def register(linter): |
| 980 """required method to auto register this checker """ |
| 981 linter.register_checker(ClassChecker(linter)) |
OLD | NEW |