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jedi-fork/jedi/inference/finder.py
2019-08-24 03:21:00 +02:00

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4.3 KiB
Python

"""
Searching for names with given scope and name. This is very central in Jedi and
Python. The name resolution is quite complicated with descripter,
``__getattribute__``, ``__getattr__``, ``global``, etc.
If you want to understand name resolution, please read the first few chapters
in http://blog.ionelmc.ro/2015/02/09/understanding-python-metaclasses/.
Flow checks
+++++++++++
Flow checks are not really mature. There's only a check for ``isinstance``. It
would check whether a flow has the form of ``if isinstance(a, type_or_tuple)``.
Unfortunately every other thing is being ignored (e.g. a == '' would be easy to
check for -> a is a string). There's big potential in these checks.
"""
from parso.tree import search_ancestor
from parso.python.tree import Name
from jedi import settings
from jedi.inference.arguments import TreeArguments
from jedi.inference import helpers
from jedi.inference.value import iterable
from jedi.inference.base_value import NO_VALUES
from jedi.parser_utils import is_scope
def filter_name(filters, name_or_str):
"""
Searches names that are defined in a scope (the different
``filters``), until a name fits.
"""
string_name = name_or_str.value if isinstance(name_or_str, Name) else name_or_str
names = []
for filter in filters:
names = filter.get(string_name)
if names:
break
return list(names)
def check_flow_information(value, flow, search_name, pos):
""" Try to find out the type of a variable just with the information that
is given by the flows: e.g. It is also responsible for assert checks.::
if isinstance(k, str):
k. # <- completion here
ensures that `k` is a string.
"""
if not settings.dynamic_flow_information:
return None
result = None
if is_scope(flow):
# Check for asserts.
module_node = flow.get_root_node()
try:
names = module_node.get_used_names()[search_name.value]
except KeyError:
return None
names = reversed([
n for n in names
if flow.start_pos <= n.start_pos < (pos or flow.end_pos)
])
for name in names:
ass = search_ancestor(name, 'assert_stmt')
if ass is not None:
result = _check_isinstance_type(value, ass.assertion, search_name)
if result is not None:
return result
if flow.type in ('if_stmt', 'while_stmt'):
potential_ifs = [c for c in flow.children[1::4] if c != ':']
for if_test in reversed(potential_ifs):
if search_name.start_pos > if_test.end_pos:
return _check_isinstance_type(value, if_test, search_name)
return result
def _check_isinstance_type(value, element, search_name):
try:
assert element.type in ('power', 'atom_expr')
# this might be removed if we analyze and, etc
assert len(element.children) == 2
first, trailer = element.children
assert first.type == 'name' and first.value == 'isinstance'
assert trailer.type == 'trailer' and trailer.children[0] == '('
assert len(trailer.children) == 3
# arglist stuff
arglist = trailer.children[1]
args = TreeArguments(value.inference_state, value, arglist, trailer)
param_list = list(args.unpack())
# Disallow keyword arguments
assert len(param_list) == 2
(key1, lazy_value_object), (key2, lazy_value_cls) = param_list
assert key1 is None and key2 is None
call = helpers.call_of_leaf(search_name)
is_instance_call = helpers.call_of_leaf(lazy_value_object.data)
# Do a simple get_code comparison. They should just have the same code,
# and everything will be all right.
normalize = value.inference_state.grammar._normalize
assert normalize(is_instance_call) == normalize(call)
except AssertionError:
return None
value_set = NO_VALUES
for cls_or_tup in lazy_value_cls.infer():
if isinstance(cls_or_tup, iterable.Sequence) and cls_or_tup.array_type == 'tuple':
for lazy_value in cls_or_tup.py__iter__():
value_set |= lazy_value.infer().execute_with_values()
else:
value_set |= cls_or_tup.execute_with_values()
return value_set