forked from VimPlug/jedi
419 lines
15 KiB
Python
419 lines
15 KiB
Python
"""
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PEP 0484 ( https://www.python.org/dev/peps/pep-0484/ ) describes type hints
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through function annotations. There is a strong suggestion in this document
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that only the type of type hinting defined in PEP0484 should be allowed
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as annotations in future python versions.
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The (initial / probably incomplete) implementation todo list for pep-0484:
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v Function parameter annotations with builtin/custom type classes
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v Function returntype annotations with builtin/custom type classes
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v Function parameter annotations with strings (forward reference)
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v Function return type annotations with strings (forward reference)
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v Local variable type hints
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v Assigned types: `Url = str\ndef get(url:Url) -> str:`
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v Type hints in `with` statements
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x Stub files support
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x support `@no_type_check` and `@no_type_check_decorator`
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x support for typing.cast() operator
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x support for type hint comments for functions, `# type: (int, str) -> int`.
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See comment from Guido https://github.com/davidhalter/jedi/issues/662
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"""
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import re
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from parso import ParserSyntaxError, parse
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from jedi._compatibility import force_unicode
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from jedi.evaluate.cache import evaluator_method_cache
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from jedi.evaluate.base_context import ContextSet, NO_CONTEXTS
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from jedi.evaluate.context.typing import TypeVar, AnnotatedClass, \
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AbstractAnnotatedClass
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from jedi.evaluate.helpers import is_string
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from jedi import debug
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from jedi import parser_utils
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def eval_annotation(context, annotation):
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"""
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Evaluates an annotation node. This means that it evaluates the part of
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`int` here:
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foo: int = 3
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Also checks for forward references (strings)
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"""
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context_set = context.eval_node(annotation)
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if len(context_set) != 1:
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debug.warning("Eval'ed typing index %s should lead to 1 object, "
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" not %s" % (annotation, context_set))
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return context_set
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evaled_context = list(context_set)[0]
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if is_string(evaled_context):
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result = _get_forward_reference_node(context, evaled_context.get_safe_value())
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if result is not None:
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return context.eval_node(result)
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return context_set
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def _evaluate_annotation_string(context, string, index=None):
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node = _get_forward_reference_node(context, string)
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if node is None:
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return NO_CONTEXTS
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context_set = context.eval_node(node)
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if index is not None:
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context_set = context_set.filter(
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lambda context: context.array_type == u'tuple' # noqa
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and len(list(context.py__iter__())) >= index
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).py__simple_getitem__(index)
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return context_set
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def _get_forward_reference_node(context, string):
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try:
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new_node = context.evaluator.grammar.parse(
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force_unicode(string),
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start_symbol='eval_input',
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error_recovery=False
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)
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except ParserSyntaxError:
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debug.warning('Annotation not parsed: %s' % string)
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return None
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else:
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module = context.tree_node.get_root_node()
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parser_utils.move(new_node, module.end_pos[0])
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new_node.parent = context.tree_node
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return new_node
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def _split_comment_param_declaration(decl_text):
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"""
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Split decl_text on commas, but group generic expressions
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together.
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For example, given "foo, Bar[baz, biz]" we return
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['foo', 'Bar[baz, biz]'].
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"""
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try:
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node = parse(decl_text, error_recovery=False).children[0]
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except ParserSyntaxError:
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debug.warning('Comment annotation is not valid Python: %s' % decl_text)
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return []
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if node.type == 'name':
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return [node.get_code().strip()]
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params = []
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try:
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children = node.children
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except AttributeError:
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return []
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else:
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for child in children:
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if child.type in ['name', 'atom_expr', 'power']:
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params.append(child.get_code().strip())
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return params
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@evaluator_method_cache()
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def infer_param(execution_context, param):
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"""
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Infers the type of a function parameter, using type annotations.
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"""
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annotation = param.annotation
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if annotation is None:
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# If no Python 3-style annotation, look for a Python 2-style comment
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# annotation.
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# Identify parameters to function in the same sequence as they would
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# appear in a type comment.
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all_params = [child for child in param.parent.children
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if child.type == 'param']
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node = param.parent.parent
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comment = parser_utils.get_following_comment_same_line(node)
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if comment is None:
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return NO_CONTEXTS
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match = re.match(r"^#\s*type:\s*\(([^#]*)\)\s*->", comment)
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if not match:
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return NO_CONTEXTS
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params_comments = _split_comment_param_declaration(match.group(1))
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# Find the specific param being investigated
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index = all_params.index(param)
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# If the number of parameters doesn't match length of type comment,
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# ignore first parameter (assume it's self).
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if len(params_comments) != len(all_params):
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debug.warning(
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"Comments length != Params length %s %s",
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params_comments, all_params
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)
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from jedi.evaluate.context.instance import InstanceArguments
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if isinstance(execution_context.var_args, InstanceArguments):
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if index == 0:
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# Assume it's self, which is already handled
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return NO_CONTEXTS
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index -= 1
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if index >= len(params_comments):
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return NO_CONTEXTS
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param_comment = params_comments[index]
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return _evaluate_annotation_string(
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execution_context.function_context.get_default_param_context(),
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param_comment
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)
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# Annotations are like default params and resolve in the same way.
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context = execution_context.function_context.get_default_param_context()
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return eval_annotation(context, annotation)
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def py__annotations__(funcdef):
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dct = {}
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for function_param in funcdef.get_params():
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param_annotation = function_param.annotation
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if param_annotation is not None:
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dct[function_param.name.value] = param_annotation
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return_annotation = funcdef.annotation
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if return_annotation:
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dct['return'] = return_annotation
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return dct
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@evaluator_method_cache()
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def infer_return_types(function_execution_context):
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"""
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Infers the type of a function's return value,
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according to type annotations.
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"""
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all_annotations = py__annotations__(function_execution_context.tree_node)
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annotation = all_annotations.get("return", None)
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if annotation is None:
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# If there is no Python 3-type annotation, look for a Python 2-type annotation
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node = function_execution_context.tree_node
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comment = parser_utils.get_following_comment_same_line(node)
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if comment is None:
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return NO_CONTEXTS
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match = re.match(r"^#\s*type:\s*\([^#]*\)\s*->\s*([^#]*)", comment)
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if not match:
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return NO_CONTEXTS
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return _evaluate_annotation_string(
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function_execution_context.function_context.get_default_param_context(),
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match.group(1).strip()
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).execute_annotation()
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if annotation is None:
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return NO_CONTEXTS
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context = function_execution_context.function_context.get_default_param_context()
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unknown_type_vars = list(find_unknown_type_vars(context, annotation))
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annotation_contexts = eval_annotation(context, annotation)
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if not unknown_type_vars:
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return annotation_contexts.execute_annotation()
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type_var_dict = infer_type_vars_for_execution(function_execution_context, all_annotations)
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def remap_type_vars(context, type_var_dict):
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"""
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The TypeVars in the resulting classes have sometimes different names
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and we need to check for that, e.g. a signature can be:
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def iter(iterable: Iterable[_T]) -> Iterator[_T]: ...
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However, the iterator is defined as Iterator[_T_co], which means it has
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a different type var name.
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"""
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try:
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func = context.list_type_vars
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except AttributeError:
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return type_var_dict
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else:
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return {
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to.py__name__(): type_var_dict.get(from_.py__name__(), NO_CONTEXTS)
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for from_, to in zip(unknown_type_vars, func())
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}
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return ContextSet(
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ann.define_generics(type_var_dict)
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if isinstance(ann, AbstractAnnotatedClass) else ann
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for ann in annotation_contexts
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).execute_annotation()
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def infer_type_vars_for_execution(execution_context, annotation_dict):
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"""
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Some functions use type vars that are not defined by the class, but rather
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only defined in the function. See for example `iter`. In those cases we
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want to:
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1. Search for undefined type vars.
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2. Infer type vars with the execution state we have.
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3. Return the union of all type vars that have been found.
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"""
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context = execution_context.function_context.get_default_param_context()
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annotation_variable_results = {}
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executed_params, _ = execution_context.get_executed_params_and_issues()
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for executed_param in executed_params:
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try:
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annotation_node = annotation_dict[executed_param.string_name]
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except KeyError:
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continue
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annotation_variables = find_unknown_type_vars(context, annotation_node)
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if annotation_variables:
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# Infer unknown type var
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annotation_context_set = context.eval_node(annotation_node)
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star_count = executed_param._param_node.star_count
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actual_context_set = executed_param.infer(use_hints=False)
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if star_count == 1:
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actual_context_set = actual_context_set.merge_types_of_iterate()
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elif star_count == 2:
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# TODO _dict_values is not public.
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actual_context_set = actual_context_set.try_merge('_dict_values')
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for ann in annotation_context_set:
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_merge_type_var_dicts(
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annotation_variable_results,
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_infer_type_vars(ann, actual_context_set),
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)
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return annotation_variable_results
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def _merge_type_var_dicts(base_dict, new_dict):
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for type_var_name, contexts in new_dict.items():
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try:
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base_dict[type_var_name] |= contexts
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except KeyError:
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base_dict[type_var_name] = contexts
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def _infer_type_vars(annotation_context, context_set):
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"""
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This function tries to find information about undefined type vars and
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returns a dict from type var name to context set.
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This is for example important to understand what `iter([1])` returns.
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According to typeshed, `iter` returns an `Iterator[_T]`:
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def iter(iterable: Iterable[_T]) -> Iterator[_T]: ...
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This functions would generate `int` for `_T` in this case, because it
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unpacks the `Iterable`.
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"""
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type_var_dict = {}
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if isinstance(annotation_context, TypeVar):
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return {annotation_context.py__name__(): context_set.py__class__()}
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elif isinstance(annotation_context, AnnotatedClass):
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name = annotation_context.py__name__()
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if name == 'Iterable':
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given = annotation_context.get_given_types()
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if given:
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for nested_annotation_context in given[0]:
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_merge_type_var_dicts(
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type_var_dict,
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_infer_type_vars(
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nested_annotation_context,
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context_set.merge_types_of_iterate()
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)
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)
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elif name == 'Mapping':
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given = annotation_context.get_given_types()
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if len(given) == 2:
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for context in context_set:
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try:
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method = context.get_mapping_item_contexts
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except AttributeError:
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continue
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key_contexts, value_contexts = method()
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for nested_annotation_context in given[0]:
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_merge_type_var_dicts(
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type_var_dict,
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_infer_type_vars(
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nested_annotation_context,
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key_contexts,
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)
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)
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for nested_annotation_context in given[1]:
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_merge_type_var_dicts(
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type_var_dict,
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_infer_type_vars(
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nested_annotation_context,
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value_contexts,
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)
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)
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return type_var_dict
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def find_type_from_comment_hint_for(context, node, name):
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return _find_type_from_comment_hint(context, node, node.children[1], name)
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def find_type_from_comment_hint_with(context, node, name):
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assert len(node.children[1].children) == 3, \
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"Can only be here when children[1] is 'foo() as f'"
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varlist = node.children[1].children[2]
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return _find_type_from_comment_hint(context, node, varlist, name)
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def find_type_from_comment_hint_assign(context, node, name):
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return _find_type_from_comment_hint(context, node, node.children[0], name)
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def _find_type_from_comment_hint(context, node, varlist, name):
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index = None
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if varlist.type in ("testlist_star_expr", "exprlist", "testlist"):
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# something like "a, b = 1, 2"
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index = 0
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for child in varlist.children:
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if child == name:
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break
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if child.type == "operator":
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continue
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index += 1
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else:
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return []
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comment = parser_utils.get_following_comment_same_line(node)
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if comment is None:
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return []
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match = re.match(r"^#\s*type:\s*([^#]*)", comment)
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if match is None:
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return []
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return _evaluate_annotation_string(
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context, match.group(1).strip(), index
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).execute_annotation()
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def find_unknown_type_vars(context, node):
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def check_node(node):
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if node.type in ('atom_expr', 'power'):
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trailer = node.children[-1]
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if trailer.type == 'trailer' and trailer.children[0] == '[':
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for subscript_node in _unpack_subscriptlist(trailer.children[1]):
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check_node(subscript_node)
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else:
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type_var_set = context.eval_node(node)
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for type_var in type_var_set:
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if isinstance(type_var, TypeVar) and type_var not in found:
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found.append(type_var)
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found = [] # We're not using a set, because the order matters.
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check_node(node)
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return found
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def _unpack_subscriptlist(subscriptlist):
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if subscriptlist.type == 'subscriptlist':
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for subscript in subscriptlist.children[::2]:
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if subscript.type != 'subscript':
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yield subscript
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else:
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if subscriptlist.type != 'subscript':
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yield subscriptlist
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