| # Copyright (c) 2006-2010 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. |
| """try to find more bugs in the code using astng inference capabilities |
| """ |
| |
| import re |
| import shlex |
| |
| from logilab import astng |
| from logilab.astng import InferenceError, NotFoundError, YES, Instance |
| |
| from pylint.interfaces import IASTNGChecker |
| from pylint.checkers import BaseChecker |
| from pylint.checkers.utils import safe_infer, is_super, check_messages |
| |
| MSGS = { |
| 'E1101': ('%s %r has no %r member', |
| 'Used when a variable is accessed for an unexistent member.'), |
| 'E1102': ('%s is not callable', |
| 'Used when an object being called has been inferred to a non \ |
| callable object'), |
| 'E1103': ('%s %r has no %r member (but some types could not be inferred)', |
| 'Used when a variable is accessed for an unexistent member, but \ |
| astng was not able to interpret all possible types of this \ |
| variable.'), |
| 'E1111': ('Assigning to function call which doesn\'t return', |
| 'Used when an assignment is done on a function call but the \ |
| inferred function doesn\'t return anything.'), |
| 'W1111': ('Assigning to function call which only returns None', |
| 'Used when an assignment is done on a function call but the \ |
| inferred function returns nothing but None.'), |
| |
| 'E1120': ('No value passed for parameter %s in function call', |
| 'Used when a function call passes too few arguments.'), |
| 'E1121': ('Too many positional arguments for function call', |
| 'Used when a function call passes too many positional \ |
| arguments.'), |
| 'E1122': ('Duplicate keyword argument %r in function call', |
| 'Used when a function call passes the same keyword argument \ |
| multiple times.'), |
| 'E1123': ('Passing unexpected keyword argument %r in function call', |
| 'Used when a function call passes a keyword argument that \ |
| doesn\'t correspond to one of the function\'s parameter names.'), |
| 'E1124': ('Multiple values passed for parameter %r in function call', |
| 'Used when a function call would result in assigning multiple \ |
| values to a function parameter, one value from a positional \ |
| argument and one from a keyword argument.'), |
| } |
| |
| class TypeChecker(BaseChecker): |
| """try to find bugs in the code using type inference |
| """ |
| |
| __implements__ = (IASTNGChecker,) |
| |
| # configuration section name |
| name = 'typecheck' |
| # messages |
| msgs = MSGS |
| priority = -1 |
| # configuration options |
| options = (('ignore-mixin-members', |
| {'default' : True, 'type' : 'yn', 'metavar': '<y_or_n>', |
| 'help' : 'Tells whether missing members accessed in mixin \ |
| class should be ignored. A mixin class is detected if its name ends with \ |
| "mixin" (case insensitive).'} |
| ), |
| |
| ('ignored-classes', |
| {'default' : ('SQLObject',), |
| 'type' : 'csv', |
| 'metavar' : '<members names>', |
| 'help' : 'List of classes names for which member attributes \ |
| should not be checked (useful for classes with attributes dynamically set).'} |
| ), |
| |
| ('zope', |
| {'default' : False, 'type' : 'yn', 'metavar': '<y_or_n>', |
| 'help' : 'When zope mode is activated, add a predefined set \ |
| of Zope acquired attributes to generated-members.'} |
| ), |
| ('generated-members', |
| {'default' : ( |
| 'REQUEST', 'acl_users', 'aq_parent'), |
| 'type' : 'string', |
| 'metavar' : '<members names>', |
| 'help' : 'List of members which are set dynamically and \ |
| missed by pylint inference system, and so shouldn\'t trigger E0201 when \ |
| accessed. Python regular expressions are accepted.'} |
| ), |
| ) |
| |
| def open(self): |
| # do this in open since config not fully initialized in __init__ |
| self.generated_members = list(self.config.generated_members) |
| if self.config.zope: |
| self.generated_members.extend(('REQUEST', 'acl_users', 'aq_parent')) |
| |
| def visit_assattr(self, node): |
| if isinstance(node.ass_type(), astng.AugAssign): |
| self.visit_getattr(node) |
| |
| def visit_delattr(self, node): |
| self.visit_getattr(node) |
| |
| @check_messages('E1101', 'E1103') |
| def visit_getattr(self, node): |
| """check that the accessed attribute exists |
| |
| to avoid to much false positives for now, we'll consider the code as |
| correct if a single of the inferred nodes has the accessed attribute. |
| |
| function/method, super call and metaclasses are ignored |
| """ |
| # generated_members may containt regular expressions |
| # (surrounded by quote `"` and followed by a comma `,`) |
| # REQUEST,aq_parent,"[a-zA-Z]+_set{1,2}"' => |
| # ('REQUEST', 'aq_parent', '[a-zA-Z]+_set{1,2}') |
| if isinstance(self.config.generated_members, str): |
| gen = shlex.shlex(self.config.generated_members) |
| gen.whitespace += ',' |
| self.config.generated_members = tuple(tok.strip('"') for tok in gen) |
| for pattern in self.config.generated_members: |
| # attribute is marked as generated, stop here |
| if re.match(pattern, node.attrname): |
| return |
| try: |
| infered = list(node.expr.infer()) |
| except InferenceError: |
| return |
| # list of (node, nodename) which are missing the attribute |
| missingattr = set() |
| ignoremim = self.config.ignore_mixin_members |
| inference_failure = False |
| for owner in infered: |
| # skip yes object |
| if owner is YES: |
| inference_failure = True |
| continue |
| # skip None anyway |
| if isinstance(owner, astng.Const) and owner.value is None: |
| continue |
| # XXX "super" / metaclass call |
| if is_super(owner) or getattr(owner, 'type', None) == 'metaclass': |
| continue |
| name = getattr(owner, 'name', 'None') |
| if name in self.config.ignored_classes: |
| continue |
| if ignoremim and name[-5:].lower() == 'mixin': |
| continue |
| try: |
| if not [n for n in owner.getattr(node.attrname) |
| if not isinstance(n.statement(), astng.AugAssign)]: |
| missingattr.add((owner, name)) |
| continue |
| except AttributeError: |
| # XXX method / function |
| continue |
| except NotFoundError: |
| if isinstance(owner, astng.Function) and owner.decorators: |
| continue |
| if isinstance(owner, Instance) and owner.has_dynamic_getattr(): |
| continue |
| # explicit skipping of optparse'Values class |
| if owner.name == 'Values' and owner.root().name == 'optparse': |
| continue |
| missingattr.add((owner, name)) |
| continue |
| # stop on the first found |
| break |
| else: |
| # we have not found any node with the attributes, display the |
| # message for infered nodes |
| done = set() |
| for owner, name in missingattr: |
| if isinstance(owner, Instance): |
| actual = owner._proxied |
| else: |
| actual = owner |
| if actual in done: |
| continue |
| done.add(actual) |
| if inference_failure: |
| msgid = 'E1103' |
| else: |
| msgid = 'E1101' |
| self.add_message(msgid, node=node, |
| args=(owner.display_type(), name, |
| node.attrname)) |
| |
| |
| def visit_assign(self, node): |
| """check that if assigning to a function call, the function is |
| possibly returning something valuable |
| """ |
| if not isinstance(node.value, astng.CallFunc): |
| return |
| function_node = safe_infer(node.value.func) |
| # skip class, generator and incomplete function definition |
| if not (isinstance(function_node, astng.Function) and |
| function_node.root().fully_defined()): |
| return |
| if function_node.is_generator() \ |
| or function_node.is_abstract(pass_is_abstract=False): |
| return |
| returns = list(function_node.nodes_of_class(astng.Return, |
| skip_klass=astng.Function)) |
| if len(returns) == 0: |
| self.add_message('E1111', node=node) |
| else: |
| for rnode in returns: |
| if not (isinstance(rnode.value, astng.Const) |
| and rnode.value.value is None): |
| break |
| else: |
| self.add_message('W1111', node=node) |
| |
| def visit_callfunc(self, node): |
| """check that called functions/methods are inferred to callable objects, |
| and that the arguments passed to the function match the parameters in |
| the inferred function's definition |
| """ |
| |
| # Build the set of keyword arguments, checking for duplicate keywords, |
| # and count the positional arguments. |
| keyword_args = set() |
| num_positional_args = 0 |
| for arg in node.args: |
| if isinstance(arg, astng.Keyword): |
| keyword = arg.arg |
| if keyword in keyword_args: |
| self.add_message('E1122', node=node, args=keyword) |
| keyword_args.add(keyword) |
| else: |
| num_positional_args += 1 |
| |
| called = safe_infer(node.func) |
| # only function, generator and object defining __call__ are allowed |
| if called is not None and not called.callable(): |
| self.add_message('E1102', node=node, args=node.func.as_string()) |
| |
| # Note that BoundMethod is a subclass of UnboundMethod (huh?), so must |
| # come first in this 'if..else'. |
| if isinstance(called, astng.BoundMethod): |
| # Bound methods have an extra implicit 'self' argument. |
| num_positional_args += 1 |
| elif isinstance(called, astng.UnboundMethod): |
| if called.decorators is not None: |
| for d in called.decorators.nodes: |
| if isinstance(d, astng.Name) and (d.name == 'classmethod'): |
| # Class methods have an extra implicit 'cls' argument. |
| num_positional_args += 1 |
| break |
| elif (isinstance(called, astng.Function) or |
| isinstance(called, astng.Lambda)): |
| pass |
| else: |
| return |
| |
| if called.args.args is None: |
| # Built-in functions have no argument information. |
| return |
| |
| if len( called.argnames() ) != len( set( called.argnames() ) ): |
| # Duplicate parameter name (see E9801). We can't really make sense |
| # of the function call in this case, so just return. |
| return |
| |
| # Analyze the list of formal parameters. |
| num_mandatory_parameters = len(called.args.args) - len(called.args.defaults) |
| parameters = [] |
| parameter_name_to_index = {} |
| for i, arg in enumerate(called.args.args): |
| if isinstance(arg, astng.Tuple): |
| name = None |
| # Don't store any parameter names within the tuple, since those |
| # are not assignable from keyword arguments. |
| else: |
| if isinstance(arg, astng.Keyword): |
| name = arg.arg |
| else: |
| assert isinstance(arg, astng.AssName) |
| # This occurs with: |
| # def f( (a), (b) ): pass |
| name = arg.name |
| parameter_name_to_index[name] = i |
| if i >= num_mandatory_parameters: |
| defval = called.args.defaults[i - num_mandatory_parameters] |
| else: |
| defval = None |
| parameters.append([(name, defval), False]) |
| |
| # Match the supplied arguments against the function parameters. |
| |
| # 1. Match the positional arguments. |
| for i in range(num_positional_args): |
| if i < len(parameters): |
| parameters[i][1] = True |
| elif called.args.vararg is not None: |
| # The remaining positional arguments get assigned to the *args |
| # parameter. |
| break |
| else: |
| # Too many positional arguments. |
| self.add_message('E1121', node=node) |
| break |
| |
| # 2. Match the keyword arguments. |
| for keyword in keyword_args: |
| if keyword in parameter_name_to_index: |
| i = parameter_name_to_index[keyword] |
| if parameters[i][1]: |
| # Duplicate definition of function parameter. |
| self.add_message('E1124', node=node, args=keyword) |
| else: |
| parameters[i][1] = True |
| elif called.args.kwarg is not None: |
| # The keyword argument gets assigned to the **kwargs parameter. |
| pass |
| else: |
| # Unexpected keyword argument. |
| self.add_message('E1123', node=node, args=keyword) |
| |
| # 3. Match the *args, if any. Note that Python actually processes |
| # *args _before_ any keyword arguments, but we wait until after |
| # looking at the keyword arguments so as to make a more conservative |
| # guess at how many values are in the *args sequence. |
| if node.starargs is not None: |
| for i in range(num_positional_args, len(parameters)): |
| [(name, defval), assigned] = parameters[i] |
| # Assume that *args provides just enough values for all |
| # non-default parameters after the last parameter assigned by |
| # the positional arguments but before the first parameter |
| # assigned by the keyword arguments. This is the best we can |
| # get without generating any false positives. |
| if (defval is not None) or assigned: |
| break |
| parameters[i][1] = True |
| |
| # 4. Match the **kwargs, if any. |
| if node.kwargs is not None: |
| for i, [(name, defval), assigned] in enumerate(parameters): |
| # Assume that *kwargs provides values for all remaining |
| # unassigned named parameters. |
| if name is not None: |
| parameters[i][1] = True |
| else: |
| # **kwargs can't assign to tuples. |
| pass |
| |
| # Check that any parameters without a default have been assigned |
| # values. |
| for [(name, defval), assigned] in parameters: |
| if (defval is None) and not assigned: |
| if name is None: |
| display = '<tuple>' |
| else: |
| display_name = repr(name) |
| self.add_message('E1120', node=node, args=display_name) |
| |
| def register(linter): |
| """required method to auto register this checker """ |
| linter.register_checker(TypeChecker(linter)) |
