(Initial) support for pep0484 annotation type hints

AUTHORS.txt

@@ -34,5 +34,6 @@ Phillip Berndt (@phillipberndt) <phillip.berndt@gmail.com>
 Ian Lee (@IanLee1521) <IanLee1521@gmail.com>
 Farkhad Khatamov (@hatamov) <comsgn@gmail.com>
 Kevin Kelley (@kelleyk) <kelleyk@kelleyk.net>
+Reinoud Elhorst (@reinhrst)
 
 Note: (@user) means a github user name.

jedi/evaluate/finder.py

@@ -23,6 +23,7 @@
 from jedi.evaluate import dynamic
 from jedi.evaluate import compiled
 from jedi.evaluate import docstrings
+from jedi.evaluate import pep0484
 from jedi.evaluate import iterable
 from jedi.evaluate import imports
 from jedi.evaluate import analysis
@@ -387,10 +388,11 @@ def _eval_param(evaluator, param, scope):
             and func.instance.is_generated and str(func.name) == '__init__':
         param = func.var.params[param.position_nr]
 
-    # Add docstring knowledge.
+    # Add pep0484 and docstring knowledge.
+    pep0484_hints = pep0484.follow_param(evaluator, param)
     doc_params = docstrings.follow_param(evaluator, param)
-    if doc_params:
-        return doc_params
+    if pep0484_hints or doc_params:
+        return list(set(pep0484_hints) | set(doc_params))
 
     if isinstance(param, ExecutedParam):
         return res_new | param.eval(evaluator)

jedi/evaluate/pep0484.py

@@ -0,0 +1,55 @@
+"""
+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)
+x Local variable type hints
+v Assigned types: `Url = str\ndef get(url:Url) -> str:`
+x Type hints in `with` statements
+x Stub files support
+x support `@no_type_check` and `@no_type_check_decorator`
+"""
+
+from itertools import chain
+from jedi.parser import Parser, load_grammar
+from jedi.evaluate.cache import memoize_default
+from jedi.evaluate.compiled import CompiledObject
+
+
+def _evaluate_for_annotation(evaluator, annotation):
+    if annotation is not None:
+        definitions = set()
+        for definition in evaluator.eval_element(annotation):
+            if (isinstance(definition, CompiledObject) and
+                    isinstance(definition.obj, str)):
+                p = Parser(load_grammar(), definition.obj)
+                try:
+                    element = p.module.children[0].children[0]
+                except (AttributeError, IndexError):
+                    continue
+                element.parent = annotation.parent
+                definitions |= evaluator.eval_element(element)
+            else:
+                definitions.add(definition)
+        return list(chain.from_iterable(
+            evaluator.execute(d) for d in definitions))
+    else:
+        return []
+
+
+@memoize_default(None, evaluator_is_first_arg=True)
+def follow_param(evaluator, param):
+    annotation = param.annotation()
+    return _evaluate_for_annotation(evaluator, annotation)
+
+
+@memoize_default(None, evaluator_is_first_arg=True)
+def find_return_types(evaluator, func):
+    annotation = func.py__annotations__().get("return", None)
+    return _evaluate_for_annotation(evaluator, annotation)

jedi/evaluate/representation.py

@@ -49,6 +49,7 @@
 from jedi.evaluate import recursion
 from jedi.evaluate import iterable
 from jedi.evaluate import docstrings
+from jedi.evaluate import pep0484
 from jedi.evaluate import helpers
 from jedi.evaluate import param
 from jedi.evaluate import flow_analysis
@@ -580,6 +581,20 @@ def py__call__(self, params):
         else:
             return FunctionExecution(self._evaluator, self, params).get_return_types()
 
+    @memoize_default()
+    def py__annotations__(self):
+        parser_func = self.base
+        return_annotation = parser_func.annotation()
+        if return_annotation:
+            dct = {'return': return_annotation}
+        else:
+            dct = {}
+        for function_param in parser_func.params:
+            param_annotation = function_param.annotation()
+            if param_annotation is not None:
+                dct[function_param.name.value] = param_annotation
+        return dct
+
     def py__class__(self):
         return compiled.get_special_object(self._evaluator, 'FUNCTION_CLASS')
 
@@ -639,6 +654,7 @@ def get_return_types(self, check_yields=False):
         else:
             returns = self.returns
             types = set(docstrings.find_return_types(self._evaluator, func))
+            types |= set(pep0484.find_return_types(self._evaluator, func))
 
         for r in returns:
             check = flow_analysis.break_check(self._evaluator, self, r)

jedi/parser/tree.py

@@ -866,7 +866,10 @@ def is_generator(self):
 
     def annotation(self):
         try:
-            return self.children[6]  # 6th element: def foo(...) -> bar
+            if self.children[3] == "->":
+                return self.children[4]
+            assert self.children[3] == ":"
+            return None
         except IndexError:
             return None
 
@@ -945,6 +948,10 @@ def params(self):
     def is_generator(self):
         return False
 
+    def annotation(self):
+        # lambda functions do not support annotations
+        return None
+
     @property
     def yields(self):
         return []
@@ -1403,8 +1410,14 @@ def default(self):
             return None
 
     def annotation(self):
-        # Generate from tfpdef.
-        raise NotImplementedError
+        tfpdef = self._tfpdef()
+        if is_node(tfpdef, 'tfpdef'):
+            assert tfpdef.children[1] == ":"
+            assert len(tfpdef.children) == 3
+            annotation = tfpdef.children[2]
+            return annotation
+        else:
+            return None
 
     def _tfpdef(self):
         """

test/completion/pep0484.py

@@ -0,0 +1,161 @@
+""" Pep-0484 type hinting """
+
+# python >= 3.2
+
+
+class A():
+    pass
+
+
+def function_parameters(a: A, b, c: str, d: int, e: str, f: str, g: int=4):
+    """
+    :param e: if docstring and annotation agree, only one should be returned
+    :type e: str
+    :param f: if docstring and annotation disagree, both should be returned
+    :type f: int
+    """
+    #? A()
+    a
+    #?
+    b
+    #? str()
+    c
+    #? int()
+    d
+    #? str()
+    e
+    #? int() str()
+    f
+    # int()
+    g
+
+
+def return_unspecified():
+    pass
+
+#?
+return_unspecified()
+
+
+def return_none() -> None:
+    """
+    Return type None means the same as no return type as far as jedi
+    is concerned
+    """
+    pass
+
+#?
+return_none()
+
+
+def return_str() -> str:
+    pass
+
+#? str()
+return_str()
+
+
+def return_custom_class() -> A:
+    pass
+
+#? A()
+return_custom_class()
+
+
+def return_annotation_and_docstring() -> str:
+    """
+    :rtype: int
+    """
+    pass
+
+#? str() int()
+return_annotation_and_docstring()
+
+
+def return_annotation_and_docstring_different() -> str:
+    """
+    :rtype: str
+    """
+    pass
+
+#? str()
+return_annotation_and_docstring_different()
+
+
+def annotation_forward_reference(b: "B") -> "B":
+    #? B()
+    b
+
+#? B()
+annotation_forward_reference(1)
+#? ["test_element"]
+annotation_forward_reference(1).t
+
+class B:
+    test_element = 1
+    pass
+
+
+class SelfReference:
+    test_element = 1
+    def test_method(self, x: "SelfReference") -> "SelfReference":
+        #? SelfReference()
+        x
+        #? ["test_element", "test_method"]
+        self.t
+        #? ["test_element", "test_method"]
+        x.t
+        #? ["test_element", "test_method"]
+        self.test_method(1).t
+
+#? SelfReference()
+SelfReference().test_method()
+
+def function_with_non_pep_0484_annotation(
+        x: "I can put anything here",
+        xx: "",
+        yy: "\r\n\0;+*&^564835(---^&*34",
+        y: 3 + 3,
+        zz: float) -> int("42"):
+    # infers int from function call
+    #? int()
+    x
+    # infers int from function call
+    #? int()
+    xx
+    # infers int from function call
+    #? int()
+    yy
+    # infers str from function call
+    #? str()
+    y
+    #? float()
+    zz
+#?
+function_with_non_pep_0484_annotation(1, 2, 3, "force string")
+
+def function_forward_reference_dynamic(
+        x: return_str_type(),
+        y: "return_str_type()") -> None:
+    # technically should not be resolvable since out of scope,
+    # but jedi is not smart enough for that
+    #? str()
+    x
+    #? str()
+    y
+
+def return_str_type():
+    return str
+
+
+X = str
+def function_with_assined_class_in_reference(x: X, y: "Y"):
+    #? str()
+    x
+    #? int()
+    y
+Y = int
+
+def just_because_we_can(x: "flo" + "at"):
+    #? float()
+    x

test/run.py

@@ -111,6 +111,7 @@
 """
 import os
 import re
+import sys
 from ast import literal_eval
 from io import StringIO
 from functools import reduce
@@ -127,15 +128,15 @@
 
 class IntegrationTestCase(object):
     def __init__(self, test_type, correct, line_nr, column, start, line,
-                 path=None):
+                 path=None, skip=None):
         self.test_type = test_type
         self.correct = correct
         self.line_nr = line_nr
         self.column = column
         self.start = start
         self.line = line
         self.path = path
-        self.skip = None
+        self.skip = skip
 
     @property
     def module_name(self):
@@ -234,10 +235,11 @@ def run_usages(self, compare_cb):
 
 def collect_file_tests(lines, lines_to_execute):
     makecase = lambda t: IntegrationTestCase(t, correct, line_nr, column,
-                                             start, line)
+                                             start, line, path=None, skip=skip)
     start = None
     correct = None
     test_type = None
+    skip = None
     for line_nr, line in enumerate(lines, 1):
         if correct is not None:
             r = re.match('^(\d+)\s*(.*)$', correct)
@@ -257,6 +259,15 @@ def collect_file_tests(lines, lines_to_execute):
                 yield makecase(TEST_DEFINITIONS)
             correct = None
         else:
+            # check for python minimal version number
+            match = re.match(r" *# *python *>= *(\d+(?:\.\d+)?)$", line)
+            if match:
+                minimal_python_version = tuple(
+                    map(int, match.group(1).split(".")))
+                if sys.version_info >= minimal_python_version:
+                    skip = None
+                else:
+                    skip = "Minimal python version %s" % match.groups(1)
             try:
                 r = re.search(r'(?:^|(?<=\s))#([?!<])\s*([^\n]*)', line)
                 # test_type is ? for completion and ! for goto_assignments