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1 | """ |
2 | Searching for names with given scope and name. This is very central in Jedi and | |
3 | Python. The name resolution is quite complicated with descripter, | |
4 | ``__getattribute__``, ``__getattr__``, ``global``, etc. | |
5 | ||
6 | If you want to understand name resolution, please read the first few chapters | |
7 | in http://blog.ionelmc.ro/2015/02/09/understanding-python-metaclasses/. | |
8 | ||
9 | Flow checks | |
10 | +++++++++++ | |
11 | ||
12 | Flow checks are not really mature. There's only a check for ``isinstance``. It | |
13 | would check whether a flow has the form of ``if isinstance(a, type_or_tuple)``. | |
14 | Unfortunately every other thing is being ignored (e.g. a == '' would be easy to | |
15 | check for -> a is a string). There's big potential in these checks. | |
16 | """ | |
17 | ||
18 | from parso.tree import search_ancestor | |
19 | from parso.python.tree import Name | |
20 | ||
21 | from jedi import settings | |
22 | from jedi.inference.arguments import TreeArguments | |
23 | from jedi.inference.value import iterable | |
24 | from jedi.inference.base_value import NO_VALUES | |
25 | from jedi.parser_utils import is_scope | |
26 | ||
27 | ||
28 | def filter_name(filters, name_or_str): | |
29 | """ | |
30 | Searches names that are defined in a scope (the different | |
31 | ``filters``), until a name fits. | |
32 | """ | |
33 | string_name = name_or_str.value if isinstance(name_or_str, Name) else name_or_str | |
34 | names = [] | |
35 | for filter in filters: | |
36 | names = filter.get(string_name) | |
37 | if names: | |
38 | break | |
39 | ||
40 | return list(_remove_del_stmt(names)) | |
41 | ||
42 | ||
43 | def _remove_del_stmt(names): | |
44 | # Catch del statements and remove them from results. | |
45 | for name in names: | |
46 | if name.tree_name is not None: | |
47 | definition = name.tree_name.get_definition() | |
48 | if definition is not None and definition.type == 'del_stmt': | |
49 | continue | |
50 | yield name | |
51 | ||
52 | ||
53 | def check_flow_information(value, flow, search_name, pos): | |
54 | """ Try to find out the type of a variable just with the information that | |
55 | is given by the flows: e.g. It is also responsible for assert checks.:: | |
56 | ||
57 | if isinstance(k, str): | |
58 | k. # <- completion here | |
59 | ||
60 | ensures that `k` is a string. | |
61 | """ | |
62 | if not settings.dynamic_flow_information: | |
63 | return None | |
64 | ||
65 | result = None | |
66 | if is_scope(flow): | |
67 | # Check for asserts. | |
68 | module_node = flow.get_root_node() | |
69 | try: | |
70 | names = module_node.get_used_names()[search_name.value] | |
71 | except KeyError: | |
72 | return None | |
73 | names = reversed([ | |
74 | n for n in names | |
75 | if flow.start_pos <= n.start_pos < (pos or flow.end_pos) | |
76 | ]) | |
77 | ||
78 | for name in names: | |
79 | ass = search_ancestor(name, 'assert_stmt') | |
80 | if ass is not None: | |
81 | result = _check_isinstance_type(value, ass.assertion, search_name) | |
82 | if result is not None: | |
83 | return result | |
84 | ||
85 | if flow.type in ('if_stmt', 'while_stmt'): | |
86 | potential_ifs = [c for c in flow.children[1::4] if c != ':'] | |
87 | for if_test in reversed(potential_ifs): | |
88 | if search_name.start_pos > if_test.end_pos: | |
89 | return _check_isinstance_type(value, if_test, search_name) | |
90 | return result | |
91 | ||
92 | ||
93 | def _get_isinstance_trailer_arglist(node): | |
94 | if node.type in ('power', 'atom_expr') and len(node.children) == 2: | |
95 | # This might be removed if we analyze and, etc | |
96 | first, trailer = node.children | |
97 | if first.type == 'name' and first.value == 'isinstance' \ | |
98 | and trailer.type == 'trailer' and trailer.children[0] == '(': | |
99 | return trailer | |
100 | return None | |
101 | ||
102 | ||
103 | def _check_isinstance_type(value, node, search_name): | |
104 | lazy_cls = None | |
105 | trailer = _get_isinstance_trailer_arglist(node) | |
106 | if trailer is not None and len(trailer.children) == 3: | |
107 | arglist = trailer.children[1] | |
108 | args = TreeArguments(value.inference_state, value, arglist, trailer) | |
109 | param_list = list(args.unpack()) | |
110 | # Disallow keyword arguments | |
111 | if len(param_list) == 2 and len(arglist.children) == 3: | |
112 | (key1, _), (key2, lazy_value_cls) = param_list | |
113 | if key1 is None and key2 is None: | |
114 | call = _get_call_string(search_name) | |
115 | is_instance_call = _get_call_string(arglist.children[0]) | |
116 | # Do a simple get_code comparison of the strings . They should | |
117 | # just have the same code, and everything will be all right. | |
118 | # There are ways that this is not correct, if some stuff is | |
119 | # redefined in between. However here we don't care, because | |
120 | # it's a heuristic that works pretty well. | |
121 | if call == is_instance_call: | |
122 | lazy_cls = lazy_value_cls | |
123 | if lazy_cls is None: | |
124 | return None | |
125 | ||
126 | value_set = NO_VALUES | |
127 | for cls_or_tup in lazy_cls.infer(): | |
128 | if isinstance(cls_or_tup, iterable.Sequence) and cls_or_tup.array_type == 'tuple': | |
129 | for lazy_value in cls_or_tup.py__iter__(): | |
130 | value_set |= lazy_value.infer().execute_with_values() | |
131 | else: | |
132 | value_set |= cls_or_tup.execute_with_values() | |
133 | return value_set | |
134 | ||
135 | ||
136 | def _get_call_string(node): | |
137 | if node.parent.type == 'atom_expr': | |
138 | return _get_call_string(node.parent) | |
139 | ||
140 | code = '' | |
141 | leaf = node.get_first_leaf() | |
142 | end = node.get_last_leaf().end_pos | |
143 | while leaf.start_pos < end: | |
144 | code += leaf.value | |
145 | leaf = leaf.get_next_leaf() | |
146 | return code |