Merge pull request #46 from christopherjwang/christopherjwang/django_…

…cached_property_support

Add support for django.utils.functional.cached_property

Pipfile

@@ -15,8 +15,9 @@ pytest-smartcov = "*"
 cython = "*"
 sphinx = "*"
 twine = "*"
+django = "*"
 
 
 [requires]
 
-python_version = "3.6"
+python_version = "3.6"

monkeytype/stubs.py

@@ -29,6 +29,11 @@
     _Union,
 )
 
+try:
+    from django.utils.functional import cached_property  # type: ignore
+except ImportError:
+    cached_property = None
+
 
 from monkeytype.tracing import (
     CallTrace,
@@ -55,6 +60,7 @@ class FunctionKind(enum.Enum):
     STATIC = 3
     # Properties are really instance methods, but this is fine for now...
     PROPERTY = 4
+    DJANGO_CACHED_PROPERTY = 5
 
     @classmethod
     def from_callable(cls, func: Callable) -> 'FunctionKind':
@@ -67,6 +73,8 @@ def from_callable(cls, func: Callable) -> 'FunctionKind':
             return FunctionKind.STATIC
         elif isinstance(func_or_desc, property):
             return FunctionKind.PROPERTY
+        elif cached_property and isinstance(func_or_desc, cached_property):
+            return FunctionKind.DJANGO_CACHED_PROPERTY
         return FunctionKind.INSTANCE
 
 
@@ -75,6 +83,7 @@ class FunctionDefinition:
         FunctionKind.CLASS,
         FunctionKind.INSTANCE,
         FunctionKind.PROPERTY,
+        FunctionKind.DJANGO_CACHED_PROPERTY,
     }
 
     def __init__(
@@ -466,6 +475,8 @@ def render(self, prefix: str = '') -> str:
             s = prefix + "@staticmethod\n" + s
         elif self.kind == FunctionKind.PROPERTY:
             s = prefix + "@property\n" + s
+        elif self.kind == FunctionKind.DJANGO_CACHED_PROPERTY:
+            s = prefix + "@cached_property\n" + s
         return s
 
     def __repr__(self) -> str:

monkeytype/tracing.py

@@ -27,6 +27,11 @@
     cast,
 )
 
+try:
+    from django.utils.functional import cached_property  # type: ignore
+except ImportError:
+    cached_property = None
+
 from monkeytype.typing import get_type
 from monkeytype.util import get_func_fqname
 
@@ -112,6 +117,8 @@ def get_func_in_mro(obj: Any, code: CodeType) -> Optional[Callable]:
         cand = cast(Callable, val.__func__)
     elif isinstance(val, property) and (val.fset is None) and (val.fdel is None):
         cand = cast(Callable, val.fget)
+    elif cached_property and isinstance(val, cached_property):
+        cand = cast(Callable, val.func)
     else:
         cand = cast(Callable, val)
     return _has_code(cand, code)

monkeytype/util.py

@@ -7,6 +7,11 @@
 import inspect
 import types
 
+try:
+    from django.utils.functional import cached_property  # type: ignore
+except ImportError:
+    cached_property = None
+
 from typing import (
     Any,
     Callable,
@@ -46,6 +51,8 @@ def get_func_in_module(module: str, qualname: str) -> Callable:
         else:
             raise InvalidTypeError(
                 f"Property {module}.{qualname} is missing getter")
+    elif cached_property and isinstance(func, cached_property):
+        func = func.func
     elif not isinstance(func, (types.FunctionType, types.BuiltinFunctionType)):
         raise InvalidTypeError(
             f"{module}.{qualname} is of type '{type(func)}', not function.")

tests/test_stubs.py

@@ -205,6 +205,15 @@ def test_property(self):
         ])
         assert stub.render() == expected
 
+    def test_cached_property(self):
+        stub = FunctionStub('test',
+                            inspect.signature(Dummy.a_cached_property.func), FunctionKind.DJANGO_CACHED_PROPERTY)
+        expected = "\n".join([
+            '@cached_property',
+            'def test%s: ...' % (render_signature(stub.signature),),
+        ])
+        assert stub.render() == expected
+
     def test_simple(self):
         for kind in [FunctionKind.MODULE, FunctionKind.INSTANCE]:
             stub = FunctionStub('test', inspect.signature(simple_add), kind)
@@ -477,6 +486,7 @@ class TestFunctionKind:
             (Dummy.a_class_method.__func__, FunctionKind.CLASS),
             (Dummy.an_instance_method, FunctionKind.INSTANCE),
             (Dummy.a_property.fget, FunctionKind.PROPERTY),
+            (Dummy.a_cached_property.func, FunctionKind.DJANGO_CACHED_PROPERTY),
             (a_module_func, FunctionKind.MODULE),
         ],
     )
@@ -492,6 +502,7 @@ class TestFunctionDefinition:
             (Dummy.a_class_method.__func__, True),
             (Dummy.an_instance_method, True),
             (Dummy.a_property.fget, True),
+            (Dummy.a_cached_property.func, True),
             (a_module_func, False),
         ],
     )
@@ -514,6 +525,9 @@ def test_has_self(self, func, expected):
             (Dummy.a_property.fget, FunctionDefinition(
                 'tests.util', 'Dummy.a_property', FunctionKind.PROPERTY,
                 Signature.from_callable(Dummy.a_property.fget))),
+            (Dummy.a_cached_property.func, FunctionDefinition(
+                'tests.util', 'Dummy.a_cached_property', FunctionKind.DJANGO_CACHED_PROPERTY,
+                Signature.from_callable(Dummy.a_cached_property.func))),
             (a_module_func, FunctionDefinition(
                 'tests.test_stubs', 'a_module_func', FunctionKind.MODULE,
                 Signature.from_callable(a_module_func))),

tests/test_tracing.py

@@ -11,6 +11,7 @@
 )
 
 import pytest
+from django.utils.functional import cached_property
 
 from monkeytype.tracing import (
     CallTrace,
@@ -69,6 +70,10 @@ def an_instance_method(self) -> Optional[FrameType]:
     def a_property(self) -> Optional[FrameType]:
         return inspect.currentframe()
 
+    @cached_property
+    def a_cached_property(self) -> Optional[FrameType]:
+        return inspect.currentframe()
+
 
 def a_module_function() -> Optional[FrameType]:
     return inspect.currentframe()
@@ -83,6 +88,7 @@ class TestGetFunc:
             (GetFuncHelper().an_instance_method(), GetFuncHelper.an_instance_method),
             (a_module_function(), a_module_function),
             (GetFuncHelper().a_property, GetFuncHelper.a_property.fget),
+            (GetFuncHelper().a_cached_property, GetFuncHelper.a_cached_property.func),
         ],
     )
     def test_get_func(self, frame, expected_func):

tests/test_util.py

@@ -61,6 +61,13 @@ def test_get_settable_property(self):
         with pytest.raises(InvalidTypeError):
             get_func_in_module(func.__module__, func.__qualname__)
 
+    def test_get_cached_property(self):
+        """We should be able to look up properties that are decorated
+        with django.utils.functional.cached_property"""
+        func = Dummy.a_cached_property.func
+        obj = get_func_in_module(func.__module__, func.__qualname__)
+        assert obj == func
+
     def test_get_non_function(self):
         """Raise an error if lookup returns something that isn't a function"""
         with pytest.raises(InvalidTypeError):

tests/util.py

@@ -11,6 +11,7 @@
     List,
     Optional,
 )
+from django.utils.functional import cached_property
 
 
 class Dummy:
@@ -37,6 +38,10 @@ def a_settable_property(self) -> Optional[FrameType]:
     def a_settable_property(self, unused) -> Optional[FrameType]:
         return inspect.currentframe()
 
+    @cached_property
+    def a_cached_property(self) -> Optional[FrameType]:
+        return inspect.currentframe()
+
 
 class Outer:
     class Inner: