# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved. # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr # # This file is part of astroid. # # astroid is free software: you can redistribute it and/or modify it # under the terms of the GNU Lesser General Public License as published by the # Free Software Foundation, either version 2.1 of the License, or (at your # option) any later version. # # astroid 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 Lesser General Public License # for more details. # # You should have received a copy of the GNU Lesser General Public License along # with astroid. If not, see . """this module contains a set of functions to handle python protocols for nodes where it makes sense. """ import collections import operator import sys from astroid import arguments from astroid import bases from astroid import context as contextmod from astroid import exceptions from astroid import node_classes from astroid import nodes from astroid import util BIN_OP_METHOD = {'+': '__add__', '-': '__sub__', '/': '__div__', '//': '__floordiv__', '*': '__mul__', '**': '__pow__', '%': '__mod__', '&': '__and__', '|': '__or__', '^': '__xor__', '<<': '__lshift__', '>>': '__rshift__', '@': '__matmul__' } UNARY_OP_METHOD = {'+': '__pos__', '-': '__neg__', '~': '__invert__', 'not': None, # XXX not '__nonzero__' } # unary operations ############################################################ def tl_infer_unary_op(self, operator): if operator == 'not': return node_classes.const_factory(not bool(self.elts)) raise TypeError() # XXX log unsupported operation nodes.Tuple.infer_unary_op = tl_infer_unary_op nodes.List.infer_unary_op = tl_infer_unary_op def dict_infer_unary_op(self, operator): if operator == 'not': return node_classes.const_factory(not bool(self.items)) raise TypeError() # XXX log unsupported operation nodes.Dict.infer_unary_op = dict_infer_unary_op def const_infer_unary_op(self, operator): if operator == 'not': return node_classes.const_factory(not self.value) # XXX log potentially raised TypeError elif operator == '+': return node_classes.const_factory(+self.value) else: # operator == '-': return node_classes.const_factory(-self.value) nodes.Const.infer_unary_op = const_infer_unary_op # binary operations ########################################################### BIN_OP_IMPL = {'+': lambda a, b: a + b, '-': lambda a, b: a - b, '/': lambda a, b: a / b, '//': lambda a, b: a // b, '*': lambda a, b: a * b, '**': lambda a, b: a ** b, '%': lambda a, b: a % b, '&': lambda a, b: a & b, '|': lambda a, b: a | b, '^': lambda a, b: a ^ b, '<<': lambda a, b: a << b, '>>': lambda a, b: a >> b, } if sys.version_info >= (3, 5): # MatMult is available since Python 3.5+. BIN_OP_IMPL['@'] = operator.matmul for key, impl in list(BIN_OP_IMPL.items()): BIN_OP_IMPL[key+'='] = impl def const_infer_binary_op(self, binop, other, context): operator = binop.op for other in other.infer(context): if isinstance(other, nodes.Const): try: impl = BIN_OP_IMPL[operator] try: yield node_classes.const_factory(impl(self.value, other.value)) except Exception: # ArithmeticError is not enough: float >> float is a TypeError # TODO : let pylint know about the problem pass except TypeError: # XXX log TypeError continue elif other is util.YES: yield other else: try: for val in other.infer_binary_op(binop, self, context): yield val except AttributeError: yield util.YES nodes.Const.infer_binary_op = bases.yes_if_nothing_inferred(const_infer_binary_op) def _multiply_seq_by_int(self, binop, other, context): node = self.__class__() node.parent = binop elts = [] for elt in self.elts: infered = util.safe_infer(elt, context) if infered is None: infered = util.YES elts.append(infered) node.elts = elts * other.value return node def _filter_uninferable_nodes(elts, context): for elt in elts: if elt is util.YES: yield elt else: for inferred in elt.infer(context): yield inferred def tl_infer_binary_op(self, binop, other, context): operator = binop.op for other in other.infer(context): if isinstance(other, self.__class__) and operator == '+': node = self.__class__() node.parent = binop elts = list(_filter_uninferable_nodes(self.elts, context)) elts += list(_filter_uninferable_nodes(other.elts, context)) node.elts = elts yield node elif isinstance(other, nodes.Const) and operator == '*': if not isinstance(other.value, int): yield util.YES continue yield _multiply_seq_by_int(self, binop, other, context) elif isinstance(other, bases.Instance) and not isinstance(other, nodes.Const): yield util.YES # XXX else log TypeError nodes.Tuple.infer_binary_op = bases.yes_if_nothing_inferred(tl_infer_binary_op) nodes.List.infer_binary_op = bases.yes_if_nothing_inferred(tl_infer_binary_op) def dict_infer_binary_op(self, binop, other, context): for other in other.infer(context): if isinstance(other, bases.Instance) and isinstance(other._proxied, nodes.ClassDef): yield util.YES # XXX else log TypeError nodes.Dict.infer_binary_op = bases.yes_if_nothing_inferred(dict_infer_binary_op) def instance_infer_binary_op(self, binop, other, context): operator = binop.op try: methods = self.getattr(BIN_OP_METHOD[operator]) except (exceptions.NotFoundError, KeyError): # Unknown operator yield util.YES else: for method in methods: if not isinstance(method, nodes.FunctionDef): continue for result in method.infer_call_result(self, context): if result is not util.YES: yield result # We are interested only in the first infered method, # don't go looking in the rest of the methods of the ancestors. break bases.Instance.infer_binary_op = bases.yes_if_nothing_inferred(instance_infer_binary_op) # assignment ################################################################## """the assigned_stmts method is responsible to return the assigned statement (e.g. not inferred) according to the assignment type. The `asspath` argument is used to record the lhs path of the original node. For instance if we want assigned statements for 'c' in 'a, (b,c)', asspath will be [1, 1] once arrived to the Assign node. The `context` argument is the current inference context which should be given to any intermediary inference necessary. """ def _resolve_looppart(parts, asspath, context): """recursive function to resolve multiple assignments on loops""" asspath = asspath[:] index = asspath.pop(0) for part in parts: if part is util.YES: continue # XXX handle __iter__ and log potentially detected errors if not hasattr(part, 'itered'): continue try: itered = part.itered() except TypeError: continue # XXX log error for stmt in itered: try: assigned = stmt.getitem(index, context) except (AttributeError, IndexError): continue except TypeError: # stmt is unsubscriptable Const continue if not asspath: # we achieved to resolved the assignment path, # don't infer the last part yield assigned elif assigned is util.YES: break else: # we are not yet on the last part of the path # search on each possibly inferred value try: for inferred in _resolve_looppart(assigned.infer(context), asspath, context): yield inferred except exceptions.InferenceError: break @bases.raise_if_nothing_inferred def for_assigned_stmts(self, node=None, context=None, asspath=None): if asspath is None: for lst in self.iter.infer(context): if isinstance(lst, (nodes.Tuple, nodes.List)): for item in lst.elts: yield item else: for inferred in _resolve_looppart(self.iter.infer(context), asspath, context): yield inferred nodes.For.assigned_stmts = for_assigned_stmts nodes.Comprehension.assigned_stmts = for_assigned_stmts def sequence_assigned_stmts(self, node=None, context=None, asspath=None): if asspath is None: asspath = [] try: index = self.elts.index(node) except ValueError: util.reraise(exceptions.InferenceError( 'Tried to retrieve a node {node!r} which does not exist', node=self, assign_path=asspath, context=context)) asspath.insert(0, index) return self.parent.assigned_stmts(node=self, context=context, asspath=asspath) nodes.Tuple.assigned_stmts = sequence_assigned_stmts nodes.List.assigned_stmts = sequence_assigned_stmts def assend_assigned_stmts(self, node=None, context=None, asspath=None): return self.parent.assigned_stmts(node=self, context=context) nodes.AssignName.assigned_stmts = assend_assigned_stmts nodes.AssignAttr.assigned_stmts = assend_assigned_stmts def _arguments_infer_argname(self, name, context): # arguments information may be missing, in which case we can't do anything # more if not (self.args or self.vararg or self.kwarg): yield util.YES return # first argument of instance/class method if self.args and getattr(self.args[0], 'name', None) == name: functype = self.parent.type if functype == 'method': yield bases.Instance(self.parent.parent.frame()) return if functype == 'classmethod': yield self.parent.parent.frame() return if context and context.callcontext: call_site = arguments.CallSite(context.callcontext) for value in call_site.infer_argument(self.parent, name, context): yield value return # TODO: just provide the type here, no need to have an empty Dict. if name == self.vararg: vararg = node_classes.const_factory(()) vararg.parent = self yield vararg return if name == self.kwarg: kwarg = node_classes.const_factory({}) kwarg.parent = self yield kwarg return # if there is a default value, yield it. And then yield YES to reflect # we can't guess given argument value try: context = contextmod.copy_context(context) for inferred in self.default_value(name).infer(context): yield inferred yield util.YES except exceptions.NoDefault: yield util.YES def arguments_assigned_stmts(self, node=None, context=None, asspath=None): if context.callcontext: # reset call context/name callcontext = context.callcontext context = contextmod.copy_context(context) context.callcontext = None args = arguments.CallSite(callcontext) return args.infer_argument(self.parent, node.name, context) return _arguments_infer_argname(self, node.name, context) nodes.Arguments.assigned_stmts = arguments_assigned_stmts @bases.raise_if_nothing_inferred def assign_assigned_stmts(self, node=None, context=None, asspath=None): if not asspath: yield self.value return for inferred in _resolve_asspart(self.value.infer(context), asspath, context): yield inferred nodes.Assign.assigned_stmts = assign_assigned_stmts nodes.AugAssign.assigned_stmts = assign_assigned_stmts def _resolve_asspart(parts, asspath, context): """recursive function to resolve multiple assignments""" asspath = asspath[:] index = asspath.pop(0) for part in parts: if hasattr(part, 'getitem'): try: assigned = part.getitem(index, context) # XXX raise a specific exception to avoid potential hiding of # unexpected exception ? except (TypeError, IndexError): return if not asspath: # we achieved to resolved the assignment path, don't infer the # last part yield assigned elif assigned is util.YES: return else: # we are not yet on the last part of the path search on each # possibly inferred value try: for inferred in _resolve_asspart(assigned.infer(context), asspath, context): yield inferred except exceptions.InferenceError: return @bases.raise_if_nothing_inferred def excepthandler_assigned_stmts(self, node=None, context=None, asspath=None): for assigned in node_classes.unpack_infer(self.type): if isinstance(assigned, nodes.ClassDef): assigned = bases.Instance(assigned) yield assigned nodes.ExceptHandler.assigned_stmts = bases.raise_if_nothing_inferred(excepthandler_assigned_stmts) @bases.raise_if_nothing_inferred def with_assigned_stmts(self, node=None, context=None, asspath=None): if asspath is None: for _, vars in self.items: if vars is None: continue for lst in vars.infer(context): if isinstance(lst, (nodes.Tuple, nodes.List)): for item in lst.nodes: yield item nodes.With.assigned_stmts = with_assigned_stmts @bases.yes_if_nothing_inferred def starred_assigned_stmts(self, node=None, context=None, asspath=None): stmt = self.statement() if not isinstance(stmt, (nodes.Assign, nodes.For)): raise exceptions.InferenceError() if isinstance(stmt, nodes.Assign): value = stmt.value lhs = stmt.targets[0] if sum(1 for node in lhs.nodes_of_class(nodes.Starred)) > 1: # Too many starred arguments in the expression. raise exceptions.InferenceError() if context is None: context = contextmod.InferenceContext() try: rhs = next(value.infer(context)) except exceptions.InferenceError: yield util.YES return if rhs is util.YES or not hasattr(rhs, 'elts'): # Not interested in inferred values without elts. yield util.YES return elts = collections.deque(rhs.elts[:]) if len(lhs.elts) > len(rhs.elts): # a, *b, c = (1, 2) raise exceptions.InferenceError() # Unpack iteratively the values from the rhs of the assignment, # until the find the starred node. What will remain will # be the list of values which the Starred node will represent # This is done in two steps, from left to right to remove # anything before the starred node and from right to left # to remvoe anything after the starred node. for index, node in enumerate(lhs.elts): if not isinstance(node, nodes.Starred): elts.popleft() continue lhs_elts = collections.deque(reversed(lhs.elts[index:])) for node in lhs_elts: if not isinstance(node, nodes.Starred): elts.pop() continue # We're done packed = nodes.List() packed.elts = elts packed.parent = self yield packed break nodes.Starred.assigned_stmts = starred_assigned_stmts