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ORPA-pyOpenRPA/WPy32-3720/python-3.7.2/Lib/site-packages/jedi/evaluate/finder.py

279 lines
12 KiB

6 years ago
"""
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.python import tree
from parso.tree import search_ancestor
from jedi import debug
from jedi import settings
from jedi.evaluate.context import AbstractInstanceContext
from jedi.evaluate import compiled
from jedi.evaluate import analysis
from jedi.evaluate import flow_analysis
from jedi.evaluate.arguments import TreeArguments
from jedi.evaluate import helpers
from jedi.evaluate.context import iterable
from jedi.evaluate.filters import get_global_filters, TreeNameDefinition
from jedi.evaluate.base_context import ContextSet
from jedi.parser_utils import is_scope, get_parent_scope
class NameFinder(object):
def __init__(self, evaluator, context, name_context, name_or_str,
position=None, analysis_errors=True):
self._evaluator = evaluator
# Make sure that it's not just a syntax tree node.
self._context = context
self._name_context = name_context
self._name = name_or_str
if isinstance(name_or_str, tree.Name):
self._string_name = name_or_str.value
else:
self._string_name = name_or_str
self._position = position
self._found_predefined_types = None
self._analysis_errors = analysis_errors
@debug.increase_indent
def find(self, filters, attribute_lookup):
"""
:params bool attribute_lookup: Tell to logic if we're accessing the
attribute or the contents of e.g. a function.
"""
names = self.filter_name(filters)
if self._found_predefined_types is not None and names:
check = flow_analysis.reachability_check(
context=self._context,
context_scope=self._context.tree_node,
node=self._name,
)
if check is flow_analysis.UNREACHABLE:
return ContextSet()
return self._found_predefined_types
types = self._names_to_types(names, attribute_lookup)
if not names and self._analysis_errors and not types \
and not (isinstance(self._name, tree.Name) and
isinstance(self._name.parent.parent, tree.Param)):
if isinstance(self._name, tree.Name):
if attribute_lookup:
analysis.add_attribute_error(
self._name_context, self._context, self._name)
else:
message = ("NameError: name '%s' is not defined."
% self._string_name)
analysis.add(self._name_context, 'name-error', self._name, message)
return types
def _get_origin_scope(self):
if isinstance(self._name, tree.Name):
scope = self._name
while scope.parent is not None:
# TODO why if classes?
if not isinstance(scope, tree.Scope):
break
scope = scope.parent
return scope
else:
return None
def get_filters(self, search_global=False):
origin_scope = self._get_origin_scope()
if search_global:
position = self._position
# For functions and classes the defaults don't belong to the
# function and get evaluated in the context before the function. So
# make sure to exclude the function/class name.
if origin_scope is not None:
ancestor = search_ancestor(origin_scope, 'funcdef', 'classdef', 'lambdef')
lambdef = None
if ancestor == 'lambdef':
# For lambdas it's even more complicated since parts will
# be evaluated later.
lambdef = ancestor
ancestor = search_ancestor(origin_scope, 'funcdef', 'classdef')
if ancestor is not None:
colon = ancestor.children[-2]
if position < colon.start_pos:
if lambdef is None or position < lambdef.children[-2].start_pos:
position = ancestor.start_pos
return get_global_filters(self._evaluator, self._context, position, origin_scope)
else:
return self._context.get_filters(search_global, self._position, origin_scope=origin_scope)
def filter_name(self, filters):
"""
Searches names that are defined in a scope (the different
``filters``), until a name fits.
"""
names = []
if self._context.predefined_names and isinstance(self._name, tree.Name):
node = self._name
while node is not None and not is_scope(node):
node = node.parent
if node.type in ("if_stmt", "for_stmt", "comp_for"):
try:
name_dict = self._context.predefined_names[node]
types = name_dict[self._string_name]
except KeyError:
continue
else:
self._found_predefined_types = types
break
for filter in filters:
names = filter.get(self._string_name)
if names:
if len(names) == 1:
n, = names
if isinstance(n, TreeNameDefinition):
# Something somewhere went terribly wrong. This
# typically happens when using goto on an import in an
# __init__ file. I think we need a better solution, but
# it's kind of hard, because for Jedi it's not clear
# that that name has not been defined, yet.
if n.tree_name == self._name:
if self._name.get_definition().type == 'import_from':
continue
break
debug.dbg('finder.filter_name %s in (%s): %s@%s',
self._string_name, self._context, names, self._position)
return list(names)
def _check_getattr(self, inst):
"""Checks for both __getattr__ and __getattribute__ methods"""
# str is important, because it shouldn't be `Name`!
name = compiled.create_simple_object(self._evaluator, self._string_name)
# This is a little bit special. `__getattribute__` is in Python
# executed before `__getattr__`. But: I know no use case, where
# this could be practical and where Jedi would return wrong types.
# If you ever find something, let me know!
# We are inversing this, because a hand-crafted `__getattribute__`
# could still call another hand-crafted `__getattr__`, but not the
# other way around.
names = (inst.get_function_slot_names(u'__getattr__') or
inst.get_function_slot_names(u'__getattribute__'))
return inst.execute_function_slots(names, name)
def _names_to_types(self, names, attribute_lookup):
contexts = ContextSet.from_sets(name.infer() for name in names)
debug.dbg('finder._names_to_types: %s -> %s', names, contexts)
if not names and isinstance(self._context, AbstractInstanceContext):
# handling __getattr__ / __getattribute__
return self._check_getattr(self._context)
# Add isinstance and other if/assert knowledge.
if not contexts and isinstance(self._name, tree.Name) and \
not isinstance(self._name_context, AbstractInstanceContext):
flow_scope = self._name
base_node = self._name_context.tree_node
if base_node.type == 'comp_for':
return contexts
while True:
flow_scope = get_parent_scope(flow_scope, include_flows=True)
n = _check_flow_information(self._name_context, flow_scope,
self._name, self._position)
if n is not None:
return n
if flow_scope == base_node:
break
return contexts
def _check_flow_information(context, 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(context, 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(context, if_test, search_name)
return result
def _check_isinstance_type(context, 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(context.evaluator, context, arglist, trailer)
param_list = list(args.unpack())
# Disallow keyword arguments
assert len(param_list) == 2
(key1, lazy_context_object), (key2, lazy_context_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_context_object.data)
# Do a simple get_code comparison. They should just have the same code,
# and everything will be all right.
normalize = context.evaluator.grammar._normalize
assert normalize(is_instance_call) == normalize(call)
except AssertionError:
return None
context_set = ContextSet()
for cls_or_tup in lazy_context_cls.infer():
if isinstance(cls_or_tup, iterable.Sequence) and cls_or_tup.array_type == 'tuple':
for lazy_context in cls_or_tup.py__iter__():
for context in lazy_context.infer():
context_set |= context.execute_evaluated()
else:
context_set |= cls_or_tup.execute_evaluated()
return context_set