Files
jedi/jedi/evaluate/pep0484.py

470 lines
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Python

"""
PEP 0484 ( https://www.python.org/dev/peps/pep-0484/ ) describes type hints
through function annotations. There is a strong suggestion in this document
that only the type of type hinting defined in PEP0484 should be allowed
as annotations in future python versions.
The (initial / probably incomplete) implementation todo list for pep-0484:
v Function parameter annotations with builtin/custom type classes
v Function returntype annotations with builtin/custom type classes
v Function parameter annotations with strings (forward reference)
v Function return type annotations with strings (forward reference)
v Local variable type hints
v Assigned types: `Url = str\ndef get(url:Url) -> str:`
v Type hints in `with` statements
x Stub files support
x support `@no_type_check` and `@no_type_check_decorator`
x support for typing.cast() operator
x support for type hint comments for functions, `# type: (int, str) -> int`.
See comment from Guido https://github.com/davidhalter/jedi/issues/662
"""
import os
import re
from collections import OrderedDict
from parso import ParserSyntaxError, parse, split_lines
from parso.python import tree
from jedi._compatibility import unicode, force_unicode
from jedi.evaluate.cache import evaluator_method_cache
from jedi.evaluate import compiled
from jedi.evaluate.base_context import NO_CONTEXTS, ContextSet, ContextWrapper
from jedi.evaluate.filters import DictFilter
from jedi.evaluate.lazy_context import LazyTreeContext
from jedi.evaluate.context import ModuleContext
from jedi.evaluate.context.typing import TypeVar, AnnotatedClass, AnnotatedSubClass
from jedi.evaluate.helpers import is_string, execute_evaluated
from jedi import debug
from jedi import parser_utils
def _evaluate_for_annotation(context, annotation, index=None):
"""
Evaluates a string-node, looking for an annotation
If index is not None, the annotation is expected to be a tuple
and we're interested in that index
"""
return context.eval_node(_fix_forward_reference(context, annotation))
def _evaluate_annotation_string(context, string, index=None):
node = _get_forward_reference_node(context, string)
if node is None:
return NO_CONTEXTS
context_set = context.eval_node(node)
if index is not None:
context_set = context_set.filter(
lambda context: context.array_type == u'tuple' # noqa
and len(list(context.py__iter__())) >= index
).py__simple_getitem__(index)
return context_set.execute_annotation()
def _fix_forward_reference(context, node):
evaled_nodes = context.eval_node(node)
if len(evaled_nodes) != 1:
debug.warning("Eval'ed typing index %s should lead to 1 object, "
" not %s" % (node, evaled_nodes))
return node
evaled_context = list(evaled_nodes)[0]
if is_string(evaled_context):
result = _get_forward_reference_node(context, evaled_context.get_safe_value())
if result is not None:
return result
return node
def _get_forward_reference_node(context, string):
try:
new_node = context.evaluator.grammar.parse(
force_unicode(string),
start_symbol='eval_input',
error_recovery=False
)
except ParserSyntaxError:
debug.warning('Annotation not parsed: %s' % string)
return None
else:
module = context.tree_node.get_root_node()
parser_utils.move(new_node, module.end_pos[0])
new_node.parent = context.tree_node
return new_node
def _split_comment_param_declaration(decl_text):
"""
Split decl_text on commas, but group generic expressions
together.
For example, given "foo, Bar[baz, biz]" we return
['foo', 'Bar[baz, biz]'].
"""
try:
node = parse(decl_text, error_recovery=False).children[0]
except ParserSyntaxError:
debug.warning('Comment annotation is not valid Python: %s' % decl_text)
return []
if node.type == 'name':
return [node.get_code().strip()]
params = []
try:
children = node.children
except AttributeError:
return []
else:
for child in children:
if child.type in ['name', 'atom_expr', 'power']:
params.append(child.get_code().strip())
return params
@evaluator_method_cache()
def infer_param(execution_context, param):
"""
Infers the type of a function parameter, using type annotations.
"""
annotation = param.annotation
if annotation is None:
# If no Python 3-style annotation, look for a Python 2-style comment
# annotation.
# Identify parameters to function in the same sequence as they would
# appear in a type comment.
all_params = [child for child in param.parent.children
if child.type == 'param']
node = param.parent.parent
comment = parser_utils.get_following_comment_same_line(node)
if comment is None:
return NO_CONTEXTS
match = re.match(r"^#\s*type:\s*\(([^#]*)\)\s*->", comment)
if not match:
return NO_CONTEXTS
params_comments = _split_comment_param_declaration(match.group(1))
# Find the specific param being investigated
index = all_params.index(param)
# If the number of parameters doesn't match length of type comment,
# ignore first parameter (assume it's self).
if len(params_comments) != len(all_params):
debug.warning(
"Comments length != Params length %s %s",
params_comments, all_params
)
from jedi.evaluate.context.instance import InstanceArguments
if isinstance(execution_context.var_args, InstanceArguments):
if index == 0:
# Assume it's self, which is already handled
return NO_CONTEXTS
index -= 1
if index >= len(params_comments):
return NO_CONTEXTS
param_comment = params_comments[index]
return _evaluate_annotation_string(
execution_context.function_context.get_default_param_context(),
param_comment
)
# Annotations are like default params and resolve in the same way.
context = execution_context.function_context.get_default_param_context()
return _evaluate_for_annotation(context, annotation).execute_annotation()
def py__annotations__(funcdef):
dct = OrderedDict()
for function_param in funcdef.get_params():
param_annotation = function_param.annotation
if param_annotation is not None:
dct[function_param.name.value] = param_annotation
return_annotation = funcdef.annotation
if return_annotation:
dct['return'] = return_annotation
return dct
@evaluator_method_cache()
def infer_return_types(function_execution_context):
"""
Infers the type of a function's return value,
according to type annotations.
"""
all_annotations = py__annotations__(function_execution_context.tree_node)
annotation = all_annotations.get("return", None)
if annotation is None:
# If there is no Python 3-type annotation, look for a Python 2-type annotation
node = function_execution_context.tree_node
comment = parser_utils.get_following_comment_same_line(node)
if comment is None:
return NO_CONTEXTS
match = re.match(r"^#\s*type:\s*\([^#]*\)\s*->\s*([^#]*)", comment)
if not match:
return NO_CONTEXTS
return _evaluate_annotation_string(
function_execution_context.function_context.get_default_param_context(),
match.group(1).strip()
)
context = function_execution_context.function_context.get_default_param_context()
return _define_type_vars(
context.eval_node(annotation),
_infer_type_vars(function_execution_context, all_annotations),
).execute_annotation()
def _infer_type_vars(execution_context, annotation_dict):
"""
Some functions use type vars that are not defined by the class, but rather
only defined in the function. See for example `iter`. In those cases we
want to:
1. Search for undefined type vars.
2. Infer type vars with the execution state we have.
3. Return the union of all type vars that have been found.
"""
context = execution_context.function_context.get_default_param_context()
try:
return_annotation = annotation_dict['return']
except KeyError:
return {}
unknown_type_vars = list(find_annotation_variables(context, return_annotation))
if not unknown_type_vars:
return {}
executed_params = execution_context.get_executed_params()
annotation_variable_results = {}
# The annotation_dict is ordered.
for i, (annotation_name, annotation_node) in enumerate(annotation_dict.items()):
if annotation_name == 'return':
continue
annotation_variables = find_annotation_variables(context, annotation_node)
if annotation_variables:
try:
param = executed_params[i]
except IndexError:
continue
# Infer unknown type var
annotation_context_set = context.eval_node(annotation_node)
actual_context_set = param.infer(use_hints=False)
for ann in annotation_context_set:
_merge_type_var_dicts(
annotation_variable_results,
_unpack_type_vars(ann, actual_context_set),
)
return annotation_variable_results
def _define_type_vars(annotation_contexts, type_var_dict):
def remap_type_vars(type_var_contexts):
return ContextSet.from_sets(
type_var_dict.get(type_var, ContextSet(type_var))
for type_var in type_var_contexts
)
if not type_var_dict:
return annotation_contexts
context_set = ContextSet()
for annotation_context in annotation_contexts:
if isinstance(annotation_context, AnnotatedClass):
context_set |= ContextSet.from_iterable([
AnnotatedSubClass(
annotation_context.evaluator,
annotation_context.parent_context,
annotation_context.tree_node,
tuple(remap_type_vars(tcs)
for tcs in annotation_context.get_given_types())
)
])
return context_set
def _merge_type_var_dicts(base_dict, new_dict):
for type_var, contexts in new_dict.items():
try:
base_dict[type_var] = contexts
except KeyError:
base_dict[type_var] |= contexts
def _unpack_type_vars(annotation_context, context_set):
type_var_dict = {}
if isinstance(annotation_context, TypeVar):
return {annotation_context: context_set.py__class__()}
elif isinstance(annotation_context, AnnotatedClass):
name = annotation_context.py__name__()
if name == 'Iterable':
given = annotation_context.get_given_types()
if given:
for nested_annotation_context in given[0]:
_merge_type_var_dicts(
type_var_dict,
_unpack_type_vars(
nested_annotation_context,
context_set.merge_types_of_iterate()
)
)
return type_var_dict
_typing_module = None
_typing_module_code_lines = None
class TypingModuleContext(ModuleContext):
"""
TODO this is currently used for recursion checks. We should just completely
refactor the typing module integration.
"""
pass
def _get_typing_replacement_module(grammar):
"""
The idea is to return our jedi replacement for the PEP-0484 typing module
as discussed at https://github.com/davidhalter/jedi/issues/663
"""
global _typing_module, _typing_module_code_lines
if _typing_module is None:
typing_path = \
os.path.abspath(os.path.join(__file__, "../jedi_typing.py"))
with open(typing_path) as f:
code = unicode(f.read())
_typing_module = grammar.parse(code)
_typing_module_code_lines = split_lines(code, keepends=True)
return _typing_module, _typing_module_code_lines
def py__simple_getitem__(context, typ, node):
if not typ.get_root_context().name.string_name == "typing":
return None
# we assume that any class using [] in a module called
# "typing" with a name for which we have a replacement
# should be replaced by that class. This is not 100%
# airtight but I don't have a better idea to check that it's
# actually the PEP-0484 typing module and not some other
if node.type == "subscriptlist":
nodes = node.children[::2] # skip the commas
else:
nodes = [node]
del node
nodes = [_fix_forward_reference(context, node) for node in nodes]
type_name = typ.name.string_name
# hacked in Union and Optional, since it's hard to do nicely in parsed code
if type_name in ("Union", '_Union'):
# In Python 3.6 it's still called typing.Union but it's an instance
# called _Union.
return ContextSet.from_sets(context.eval_node(node) for node in nodes)
if type_name in ("Optional", '_Optional'):
# Here we have the same issue like in Union. Therefore we also need to
# check for the instance typing._Optional (Python 3.6).
return context.eval_node(nodes[0])
module_node, code_lines = _get_typing_replacement_module(context.evaluator.latest_grammar)
typing = TypingModuleContext(
context.evaluator,
module_node=module_node,
path=None,
code_lines=code_lines,
)
factories = typing.py__getattribute__("factory")
assert len(factories) == 1
factory = list(factories)[0]
assert factory
function_body_nodes = factory.tree_node.children[4].children
valid_classnames = set(child.name.value
for child in function_body_nodes
if isinstance(child, tree.Class))
if type_name not in valid_classnames:
return None
compiled_classname = compiled.create_simple_object(context.evaluator, type_name)
from jedi.evaluate.context.iterable import FakeSequence
args = FakeSequence(
context.evaluator,
u'tuple',
[LazyTreeContext(context, n) for n in nodes]
)
result = execute_evaluated(factory, compiled_classname, args)
return result
def find_type_from_comment_hint_for(context, node, name):
return _find_type_from_comment_hint(context, node, node.children[1], name)
def find_type_from_comment_hint_with(context, node, name):
assert len(node.children[1].children) == 3, \
"Can only be here when children[1] is 'foo() as f'"
varlist = node.children[1].children[2]
return _find_type_from_comment_hint(context, node, varlist, name)
def find_type_from_comment_hint_assign(context, node, name):
return _find_type_from_comment_hint(context, node, node.children[0], name)
def _find_type_from_comment_hint(context, node, varlist, name):
index = None
if varlist.type in ("testlist_star_expr", "exprlist", "testlist"):
# something like "a, b = 1, 2"
index = 0
for child in varlist.children:
if child == name:
break
if child.type == "operator":
continue
index += 1
else:
return []
comment = parser_utils.get_following_comment_same_line(node)
if comment is None:
return []
match = re.match(r"^#\s*type:\s*([^#]*)", comment)
if match is None:
return []
return _evaluate_annotation_string(context, match.group(1).strip(), index)
def find_annotation_variables(context, node):
found = []
if node.type == 'atom_expr':
trailer = node.children[-1]
if trailer.type == 'trailer' and trailer.children[0] == '[':
for subscript_node in _unpack_subscriptlist(trailer.children[1]):
type_var_set = context.eval_node(subscript_node)
for type_var in type_var_set:
from jedi.evaluate.context.typing import TypeVar
if isinstance(type_var, TypeVar) and type_var not in found:
found.append(type_var)
return found
def _unpack_subscriptlist(subscriptlist):
if subscriptlist.type == 'subscriptlist':
for subscript in subscriptlist.children[::2]:
if subscript.type != 'subscript':
yield subscript
else:
if subscriptlist.type != 'subscript':
yield subscriptlist