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