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