"""

Functions evaluating the syntax tree.

"""

import copy

from parso.python import tree

from jedi._compatibility import force_unicode, unicode

from jedi import debug

from jedi import parser_utils

from jedi.evaluate.base_context import ContextSet, NO_CONTEXTS, ContextualizedNode, \

ContextualizedName, iterator_to_context_set, iterate_contexts

from jedi.evaluate import compiled

from jedi.evaluate import pep0484

from jedi.evaluate import recursion

from jedi.evaluate import helpers

from jedi.evaluate import analysis

from jedi.evaluate import imports

from jedi.evaluate import arguments

from jedi.evaluate.pep0484 import _evaluate_for_annotation

from jedi.evaluate.context import ClassContext, FunctionContext

from jedi.evaluate.context import iterable

from jedi.evaluate.context import TreeInstance, CompiledInstance

from jedi.evaluate.finder import NameFinder

from jedi.evaluate.helpers import is_string, is_literal, is_number, is_compiled

from jedi.evaluate.compiled.access import COMPARISON_OPERATORS

def _limit_context_infers(func):

"""

This is for now the way how we limit type inference going wild. There are

other ways to ensure recursion limits as well. This is mostly necessary

because of instance (self) access that can be quite tricky to limit.

I'm still not sure this is the way to go, but it looks okay for now and we

can still go anther way in the future. Tests are there. ~ dave

"""

def wrapper(context, *args, **kwargs):

n = context.tree_node

evaluator = context.evaluator

try:

evaluator.inferred_element_counts[n] += 1

if evaluator.inferred_element_counts[n] > 300:

debug.warning('In context %s there were too many inferences.', n)

return NO_CONTEXTS

except KeyError:

evaluator.inferred_element_counts[n] = 1

return func(context, *args, **kwargs)

return wrapper

def _py__stop_iteration_returns(generators):

results = ContextSet()

for generator in generators:

try:

method = generator.py__stop_iteration_returns

except AttributeError:

debug.warning('%s is not actually a generator', generator)

else:

results |= method()

return results

@debug.increase_indent

@_limit_context_infers

def eval_node(context, element):

debug.dbg('eval_node %s@%s', element, element.start_pos)

evaluator = context.evaluator

typ = element.type

if typ in ('name', 'number', 'string', 'atom', 'strings'):

return eval_atom(context, element)

elif typ == 'keyword':

# For False/True/None

if element.value in ('False', 'True', 'None'):

return ContextSet(compiled.builtin_from_name(evaluator, element.value))

# else: print e.g. could be evaluated like this in Python 2.7

return NO_CONTEXTS

elif typ == 'lambdef':

return ContextSet(FunctionContext(evaluator, context, element))

elif typ == 'expr_stmt':

return eval_expr_stmt(context, element)

elif typ in ('power', 'atom_expr'):

first_child = element.children[0]

children = element.children[1:]

had_await = False

if first_child.type == 'keyword' and first_child.value == 'await':

had_await = True

first_child = children.pop(0)

context_set = eval_atom(context, first_child)

for trailer in children:

if trailer == '**': # has a power operation.

right = context.eval_node(children[1])

context_set = _eval_comparison(

evaluator,

context,

context_set,

trailer,

right

)

break

context_set = eval_trailer(context, context_set, trailer)

if had_await:

await_context_set = context_set.py__getattribute__(u"__await__")

if not await_context_set:

debug.warning('Tried to run py__await__ on context %s', context)

context_set = ContextSet()

return _py__stop_iteration_returns(await_context_set.execute_evaluated())

return context_set

elif typ in ('testlist_star_expr', 'testlist',):

# The implicit tuple in statements.

return ContextSet(iterable.SequenceLiteralContext(evaluator, context, element))

elif typ in ('not_test', 'factor'):

context_set = context.eval_node(element.children[-1])

for operator in element.children[:-1]:

context_set = eval_factor(context_set, operator)

return context_set

elif typ == 'test':

# `x if foo else y` case.

return (context.eval_node(element.children[0]) |

context.eval_node(element.children[-1]))

elif typ == 'operator':

# Must be an ellipsis, other operators are not evaluated.

# In Python 2 ellipsis is coded as three single dot tokens, not

# as one token 3 dot token.

if element.value not in ('.', '...'):

origin = element.parent

raise AssertionError("unhandled operator %s in %s " % (repr(element.value), origin))

return ContextSet(compiled.builtin_from_name(evaluator, u'Ellipsis'))

elif typ == 'dotted_name':

context_set = eval_atom(context, element.children[0])

for next_name in element.children[2::2]:

# TODO add search_global=True?

context_set = context_set.py__getattribute__(next_name, name_context=context)

return context_set

elif typ == 'eval_input':

return eval_node(context, element.children[0])

elif typ == 'annassign':

return pep0484._evaluate_for_annotation(context, element.children[1])

elif typ == 'yield_expr':

if len(element.children) and element.children[1].type == 'yield_arg':

# Implies that it's a yield from.

element = element.children[1].children[1]

generators = context.eval_node(element)

return _py__stop_iteration_returns(generators)

# Generator.send() is not implemented.

return NO_CONTEXTS

else:

return eval_or_test(context, element)

def eval_trailer(context, base_contexts, trailer):

trailer_op, node = trailer.children[:2]

if node == ')': # `arglist` is optional.

node = None

if trailer_op == '[':

trailer_op, node, _ = trailer.children

# TODO It's kind of stupid to cast this from a context set to a set.

foo = set(base_contexts)

# special case: PEP0484 typing module, see

# https://github.com/davidhalter/jedi/issues/663

result = ContextSet()

for typ in list(foo):

if isinstance(typ, (ClassContext, TreeInstance)):

typing_module_types = pep0484.py__getitem__(context, typ, node)

if typing_module_types is not None:

foo.remove(typ)

result |= typing_module_types

return result | base_contexts.get_item(

eval_subscript_list(context.evaluator, context, node),

ContextualizedNode(context, trailer)

)

else:

debug.dbg('eval_trailer: %s in %s', trailer, base_contexts)

if trailer_op == '.':

return base_contexts.py__getattribute__(

name_context=context,

name_or_str=node

)

else:

assert trailer_op == '(', 'trailer_op is actually %s' % trailer_op

args = arguments.TreeArguments(context.evaluator, context, node, trailer)

return base_contexts.execute(args)

def eval_atom(context, atom):

"""

Basically to process ``atom`` nodes. The parser sometimes doesn't

generate the node (because it has just one child). In that case an atom

might be a name or a literal as well.

"""

if atom.type == 'name':

# This is the first global lookup.

stmt = tree.search_ancestor(

atom, 'expr_stmt', 'lambdef'

) or atom

if stmt.type == 'lambdef':

stmt = atom

return context.py__getattribute__(

name_or_str=atom,

position=stmt.start_pos,

search_global=True

)

elif isinstance(atom, tree.Literal):

string = context.evaluator.compiled_subprocess.safe_literal_eval(atom.value)

return ContextSet(compiled.create_simple_object(context.evaluator, string))

elif atom.type == 'strings':

# Will be multiple string.

context_set = eval_atom(context, atom.children[0])

for string in atom.children[1:]:

right = eval_atom(context, string)

context_set = _eval_comparison(context.evaluator, context, context_set, u'+', right)

return context_set

else:

c = atom.children

# Parentheses without commas are not tuples.

if c[0] == '(' and not len(c) == 2 \

and not(c[1].type == 'testlist_comp' and

len(c[1].children) > 1):

return context.eval_node(c[1])

try:

comp_for = c[1].children[1]

except (IndexError, AttributeError):

pass

else:

if comp_for == ':':

# Dict comprehensions have a colon at the 3rd index.

try:

comp_for = c[1].children[3]

except IndexError:

pass

if comp_for.type == 'comp_for':

return ContextSet(iterable.comprehension_from_atom(

context.evaluator, context, atom

))

# It's a dict/list/tuple literal.

array_node = c[1]

try:

array_node_c = array_node.children

except AttributeError:

array_node_c = []

if c[0] == '{' and (array_node == '}' or ':' in array_node_c):

context = iterable.DictLiteralContext(context.evaluator, context, atom)

else:

context = iterable.SequenceLiteralContext(context.evaluator, context, atom)

return ContextSet(context)

@_limit_context_infers

def eval_expr_stmt(context, stmt, seek_name=None):

with recursion.execution_allowed(context.evaluator, stmt) as allowed:

# Here we allow list/set to recurse under certain conditions. To make

# it possible to resolve stuff like list(set(list(x))), this is

# necessary.

if not allowed and context.get_root_context() == context.evaluator.builtins_module:

try:

instance = context.instance

except AttributeError:

pass

else:

if instance.name.string_name in ('list', 'set'):

c = instance.get_first_non_keyword_argument_contexts()

if instance not in c:

allowed = True

if allowed:

return _eval_expr_stmt(context, stmt, seek_name)

return NO_CONTEXTS

@debug.increase_indent

def _eval_expr_stmt(context, stmt, seek_name=None):

"""

The starting point of the completion. A statement always owns a call

list, which are the calls, that a statement does. In case multiple

names are defined in the statement, `seek_name` returns the result for

this name.

:param stmt: A `tree.ExprStmt`.

"""

debug.dbg('eval_expr_stmt %s (%s)', stmt, seek_name)

rhs = stmt.get_rhs()

context_set = context.eval_node(rhs)

if seek_name:

c_node = ContextualizedName(context, seek_name)

context_set = check_tuple_assignments(context.evaluator, c_node, context_set)

first_operator = next(stmt.yield_operators(), None)

if first_operator not in ('=', None) and first_operator.type == 'operator':

# `=` is always the last character in aug assignments -> -1

operator = copy.copy(first_operator)

operator.value = operator.value[:-1]

name = stmt.get_defined_names()[0].value

left = context.py__getattribute__(

name, position=stmt.start_pos, search_global=True)

for_stmt = tree.search_ancestor(stmt, 'for_stmt')

if for_stmt is not None and for_stmt.type == 'for_stmt' and context_set \

and parser_utils.for_stmt_defines_one_name(for_stmt):

# Iterate through result and add the values, that's possible

# only in for loops without clutter, because they are

# predictable. Also only do it, if the variable is not a tuple.

node = for_stmt.get_testlist()

cn = ContextualizedNode(context, node)

ordered = list(cn.infer().iterate(cn))

for lazy_context in ordered:

dct = {for_stmt.children[1].value: lazy_context.infer()}

with helpers.predefine_names(context, for_stmt, dct):

t = context.eval_node(rhs)

left = _eval_comparison(context.evaluator, context, left, operator, t)

context_set = left

else:

context_set = _eval_comparison(context.evaluator, context, left, operator, context_set)

debug.dbg('eval_expr_stmt result %s', context_set)

return context_set

def eval_or_test(context, or_test):

iterator = iter(or_test.children)

types = context.eval_node(next(iterator))

for operator in iterator:

right = next(iterator)

if operator.type == 'comp_op': # not in / is not

operator = ' '.join(c.value for c in operator.children)

# handle lazy evaluation of and/or here.

if operator in ('and', 'or'):

left_bools = set(left.py__bool__() for left in types)

if left_bools == {True}:

if operator == 'and':

types = context.eval_node(right)

elif left_bools == {False}:

if operator != 'and':

types = context.eval_node(right)

# Otherwise continue, because of uncertainty.

else:

types = _eval_comparison(context.evaluator, context, types, operator,

context.eval_node(right))

debug.dbg('eval_or_test types %s', types)

return types

@iterator_to_context_set

def eval_factor(context_set, operator):

"""

Calculates `+`, `-`, `~` and `not` prefixes.

"""

for context in context_set:

if operator == '-':

if is_number(context):

yield context.negate()

elif operator == 'not':

value = context.py__bool__()

if value is None: # Uncertainty.

return

yield compiled.create_simple_object(context.evaluator, not value)

else:

yield context

def _literals_to_types(evaluator, result):

# Changes literals ('a', 1, 1.0, etc) to its type instances (str(),

# int(), float(), etc).

new_result = NO_CONTEXTS

for typ in result:

if is_literal(typ):

# Literals are only valid as long as the operations are

# correct. Otherwise add a value-free instance.

cls = compiled.builtin_from_name(evaluator, typ.name.string_name)

new_result |= cls.execute_evaluated()

else:

new_result |= ContextSet(typ)

return new_result

def _eval_comparison(evaluator, context, left_contexts, operator, right_contexts):

if not left_contexts or not right_contexts:

# illegal slices e.g. cause left/right_result to be None

result = (left_contexts or NO_CONTEXTS) | (right_contexts or NO_CONTEXTS)

return _literals_to_types(evaluator, result)

else:

# I don't think there's a reasonable chance that a string

# operation is still correct, once we pass something like six

# objects.

if len(left_contexts) * len(right_contexts) > 6:

return _literals_to_types(evaluator, left_contexts | right_contexts)

else:

return ContextSet.from_sets(

_eval_comparison_part(evaluator, context, left, operator, right)

for left in left_contexts

for right in right_contexts

)

def _is_tuple(context):

return isinstance(context, iterable.Sequence) and context.array_type == 'tuple'

def _is_list(context):

return isinstance(context, iterable.Sequence) and context.array_type == 'list'

def _bool_to_context(evaluator, bool_):

return compiled.builtin_from_name(evaluator, force_unicode(str(bool_)))

def _eval_comparison_part(evaluator, context, left, operator, right):

l_is_num = is_number(left)

r_is_num = is_number(right)

if isinstance(operator, unicode):

str_operator = operator

else:

str_operator = force_unicode(str(operator.value))

if str_operator == '*':

# for iterables, ignore * operations

if isinstance(left, iterable.Sequence) or is_string(left):

return ContextSet(left)

elif isinstance(right, iterable.Sequence) or is_string(right):

return ContextSet(right)

elif str_operator == '+':

if l_is_num and r_is_num or is_string(left) and is_string(right):

return ContextSet(left.execute_operation(right, str_operator))

elif _is_tuple(left) and _is_tuple(right) or _is_list(left) and _is_list(right):

return ContextSet(iterable.MergedArray(evaluator, (left, right)))

elif str_operator == '-':

if l_is_num and r_is_num:

return ContextSet(left.execute_operation(right, str_operator))

elif str_operator == '%':

# With strings and numbers the left type typically remains. Except for

# `int() % float()`.

return ContextSet(left)

elif str_operator in COMPARISON_OPERATORS:

if is_compiled(left) and is_compiled(right):

# Possible, because the return is not an option. Just compare.

try:

return ContextSet(left.execute_operation(right, str_operator))

except TypeError:

# Could be True or False.

pass

else:

if str_operator in ('is', '!=', '==', 'is not'):

operation = COMPARISON_OPERATORS[str_operator]

bool_ = operation(left, right)

return ContextSet(_bool_to_context(evaluator, bool_))

return ContextSet(_bool_to_context(evaluator, True), _bool_to_context(evaluator, False))

elif str_operator == 'in':

return NO_CONTEXTS

def check(obj):

"""Checks if a Jedi object is either a float or an int."""

return isinstance(obj, CompiledInstance) and \

obj.name.string_name in ('int', 'float')

# Static analysis, one is a number, the other one is not.

if str_operator in ('+', '-') and l_is_num != r_is_num \

and not (check(left) or check(right)):

message = "TypeError: unsupported operand type(s) for +: %s and %s"

analysis.add(context, 'type-error-operation', operator,

message % (left, right))

return ContextSet(left, right)

def _remove_statements(evaluator, context, stmt, name):

"""

This is the part where statements are being stripped.

Due to lazy evaluation, statements like a = func; b = a; b() have to be

evaluated.

"""

pep0484_contexts = \

pep0484.find_type_from_comment_hint_assign(context, stmt, name)

if pep0484_contexts:

return pep0484_contexts

return eval_expr_stmt(context, stmt, seek_name=name)

def tree_name_to_contexts(evaluator, context, tree_name):

context_set = ContextSet()

module_node = context.get_root_context().tree_node

if module_node is not None:

names = module_node.get_used_names().get(tree_name.value, [])

for name in names:

expr_stmt = name.parent

correct_scope = parser_utils.get_parent_scope(name) == context.tree_node

if expr_stmt.type == "expr_stmt" and expr_stmt.children[1].type == "annassign" and correct_scope:

context_set |= _evaluate_for_annotation(context, expr_stmt.children[1].children[1])

if context_set:

return context_set

types = []

node = tree_name.get_definition(import_name_always=True)

if node is None:

node = tree_name.parent

if node.type == 'global_stmt':

context = evaluator.create_context(context, tree_name)

finder = NameFinder(evaluator, context, context, tree_name.value)

filters = finder.get_filters(search_global=True)

# For global_stmt lookups, we only need the first possible scope,

# which means the function itself.

filters = [next(filters)]

return finder.find(filters, attribute_lookup=False)

elif node.type not in ('import_from', 'import_name'):

raise ValueError("Should not happen. type: %s", node.type)

typ = node.type

if typ == 'for_stmt':

types = pep0484.find_type_from_comment_hint_for(context, node, tree_name)

if types:

return types

if typ == 'with_stmt':

types = pep0484.find_type_from_comment_hint_with(context, node, tree_name)

if types:

return types

if typ in ('for_stmt', 'comp_for'):

try:

types = context.predefined_names[node][tree_name.value]

except KeyError:

cn = ContextualizedNode(context, node.children[3])

for_types = iterate_contexts(

cn.infer(),

contextualized_node=cn,

is_async=node.parent.type == 'async_stmt',

)

c_node = ContextualizedName(context, tree_name)

types = check_tuple_assignments(evaluator, c_node, for_types)

elif typ == 'expr_stmt':

types = _remove_statements(evaluator, context, node, tree_name)

elif typ == 'with_stmt':

context_managers = context.eval_node(node.get_test_node_from_name(tree_name))

enter_methods = context_managers.py__getattribute__(u'__enter__')

return enter_methods.execute_evaluated()

elif typ in ('import_from', 'import_name'):

types = imports.infer_import(context, tree_name)

elif typ in ('funcdef', 'classdef'):

types = _apply_decorators(context, node)

elif typ == 'try_stmt':

# TODO an exception can also be a tuple. Check for those.

# TODO check for types that are not classes and add it to

# the static analysis report.

exceptions = context.eval_node(tree_name.get_previous_sibling().get_previous_sibling())

types = exceptions.execute_evaluated()

else:

raise ValueError("Should not happen. type: %s" % typ)

return types

def _apply_decorators(context, node):

"""

Returns the function, that should to be executed in the end.

This is also the places where the decorators are processed.

"""

if node.type == 'classdef':

decoratee_context = ClassContext(

context.evaluator,

parent_context=context,

classdef=node

)

else:

decoratee_context = FunctionContext(

context.evaluator,

parent_context=context,

funcdef=node

)

initial = values = ContextSet(decoratee_context)

for dec in reversed(node.get_decorators()):

debug.dbg('decorator: %s %s', dec, values)

dec_values = context.eval_node(dec.children[1])

trailer_nodes = dec.children[2:-1]

if trailer_nodes:

# Create a trailer and evaluate it.

trailer = tree.PythonNode('trailer', trailer_nodes)

trailer.parent = dec

dec_values = eval_trailer(context, dec_values, trailer)

if not len(dec_values):

debug.warning('decorator not found: %s on %s', dec, node)

return initial

values = dec_values.execute(arguments.ValuesArguments([values]))

if not len(values):

debug.warning('not possible to resolve wrappers found %s', node)

return initial

debug.dbg('decorator end %s', values)

return values

def check_tuple_assignments(evaluator, contextualized_name, context_set):

"""

Checks if tuples are assigned.

"""

lazy_context = None

for index, node in contextualized_name.assignment_indexes():

cn = ContextualizedNode(contextualized_name.context, node)

iterated = context_set.iterate(cn)

for _ in range(index + 1):

try:

lazy_context = next(iterated)

except StopIteration:

# We could do this with the default param in next. But this

# would allow this loop to run for a very long time if the

# index number is high. Therefore break if the loop is

# finished.

return ContextSet()

context_set = lazy_context.infer()

return context_set

def eval_subscript_list(evaluator, context, index):

"""

Handles slices in subscript nodes.

"""

if index == ':':

# Like array[:]

return ContextSet(iterable.Slice(context, None, None, None))

elif index.type == 'subscript' and not index.children[0] == '.':

# subscript basically implies a slice operation, except for Python 2's

# Ellipsis.

# e.g. array[:3]

result = []

for el in index.children:

if el == ':':

if not result:

result.append(None)

elif el.type == 'sliceop':

if len(el.children) == 2:

result.append(el.children[1])

else:

result.append(el)

result += [None] * (3 - len(result))

return ContextSet(iterable.Slice(context, *result))

elif index.type == 'subscriptlist':

return NO_CONTEXTS

# No slices

return context.eval_node(index)