hub/venv/lib/python3.7/site-packages/jedi/inference/finder.py

147 lines
5.2 KiB
Python
Raw Normal View History

"""
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.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(_remove_del_stmt(names))
def _remove_del_stmt(names):
# Catch del statements and remove them from results.
for name in names:
if name.tree_name is not None:
definition = name.tree_name.get_definition()
if definition is not None and definition.type == 'del_stmt':
continue
yield name
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 _get_isinstance_trailer_arglist(node):
if node.type in ('power', 'atom_expr') and len(node.children) == 2:
# This might be removed if we analyze and, etc
first, trailer = node.children
if first.type == 'name' and first.value == 'isinstance' \
and trailer.type == 'trailer' and trailer.children[0] == '(':
return trailer
return None
def _check_isinstance_type(value, node, search_name):
lazy_cls = None
trailer = _get_isinstance_trailer_arglist(node)
if trailer is not None and len(trailer.children) == 3:
arglist = trailer.children[1]
args = TreeArguments(value.inference_state, value, arglist, trailer)
param_list = list(args.unpack())
# Disallow keyword arguments
if len(param_list) == 2 and len(arglist.children) == 3:
(key1, _), (key2, lazy_value_cls) = param_list
if key1 is None and key2 is None:
call = _get_call_string(search_name)
is_instance_call = _get_call_string(arglist.children[0])
# Do a simple get_code comparison of the strings . They should
# just have the same code, and everything will be all right.
# There are ways that this is not correct, if some stuff is
# redefined in between. However here we don't care, because
# it's a heuristic that works pretty well.
if call == is_instance_call:
lazy_cls = lazy_value_cls
if lazy_cls is None:
return None
value_set = NO_VALUES
for cls_or_tup in lazy_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
def _get_call_string(node):
if node.parent.type == 'atom_expr':
return _get_call_string(node.parent)
code = ''
leaf = node.get_first_leaf()
end = node.get_last_leaf().end_pos
while leaf.start_pos < end:
code += leaf.value
leaf = leaf.get_next_leaf()
return code