Use dir instead of getmembers (#879)

* Use dir instead of getmembers

* Add property decorator tests

* Use cpython api function for dir

* Don't try to test properties

* Check if return value is NULL

* Deprecate keys

* Add deprecation test

Author: sethaxen

src/PyCall.jl

@@ -316,7 +316,11 @@ function trygetproperty(o::PyObject, s::AbstractString, d)
     return p == C_NULL ? d : PyObject(p)
 end
 
-propertynames(o::PyObject) = ispynull(o) ? Symbol[] : map(x->Symbol(first(x)), PyIterator{PyObject}(pycall(inspect."getmembers", PyObject, o)))
+function propertynames(o::PyObject)
+    ispynull(o) && return Symbol[]
+    names = @pycheckn ccall((@pysym :PyObject_Dir), PyObject, (PyPtr,), o)
+    return convert(Vector{Symbol}, names)
+end
 
 # avoiding method ambiguity
 setproperty!(o::PyObject, s::Symbol, v) = _setproperty!(o,s,v)
@@ -366,8 +370,7 @@ hasproperty(o::PyObject, s::AbstractString) = pyhasproperty(o, s)
 
 #########################################################################
 
-keys(o::PyObject) = Symbol[m[1] for m in pycall(inspect."getmembers",
-                                PyVector{Tuple{Symbol,PyObject}}, o)]
+@deprecate keys(o::PyObject) propertynames(o)
 
 #########################################################################
 # Create anonymous composite w = pywrap(o) wrapping the object o

test/runtests.jl

@@ -295,17 +295,22 @@ const PyInt = pyversion < v"3" ? Int : Clonglong
     class A:
         class B:
             C = 1
+            @property
+            def D(self):
+                raise NotImplementedError
     """
     A = py"A"
     @test hasproperty(A, "B")
     @test getproperty(A, "B") == py"A.B"
     @test :B in propertynames(A)
     @static if VERSION >= v"0.7-"
+        @test :D in propertynames(A.B)
         @test A.B.C == 1
         @test_throws KeyError A.X
     end
     setproperty!(py"A.B", "C", 2)
     @test py"A.B.C" == 2
+    @test_deprecated keys(A)
 
     # buffers
     let b = PyCall.PyBuffer(pyutf8("test string"))
@@ -317,7 +322,7 @@ const PyInt = pyversion < v"3" ? Int : Clonglong
 
     let o = PyObject(1+2im)
         @test PyCall.hasproperty(o, :real) # replace by Base.hasproperty in the future
-        @test :real in keys(o)
+        @test :real in propertynames(o)
         @test o.real == 1
     end