fix getproperty exceptions (#997)

* raise proper exception in getproperty

* Update src/PyCall.jl

* Update src/PyCall.jl

* whoops

* also fix setproperty

* Update src/PyCall.jl

* Update src/PyCall.jl

* Update src/PyCall.jl

* Update src/PyCall.jl

Co-authored-by: Steven G. Johnson <stevenj@mit.edu>

Author: aplavin

src/PyCall.jl

@@ -298,7 +298,13 @@ end
 function _getproperty(o::PyObject, s::Union{AbstractString,Symbol})
     ispynull(o) && throw(ArgumentError("ref of NULL PyObject"))
     p = ccall((@pysym :PyObject_GetAttrString), PyPtr, (PyPtr, Cstring), o, s)
-    p == C_NULL && pyerr_clear()
+    if p == C_NULL && pyerr_occurred()
+        e = pyerror("PyObject_GetAttrString")
+        if PyPtr(e.T) != @pyglobalobjptr(:PyExc_AttributeError)
+            throw(e)
+        end
+        pyerr_clear()
+    end
     return p
 end
 
@@ -327,15 +333,17 @@ setproperty!(o::PyObject, s::Symbol, v) = _setproperty!(o,s,v)
 setproperty!(o::PyObject, s::AbstractString, v) = _setproperty!(o,s,v)
 
 function _setproperty!(o::PyObject, s::Union{Symbol,AbstractString}, v)
-    if ispynull(o)
-        throw(ArgumentError("assign of NULL PyObject"))
-    end
-    if -1 == ccall((@pysym :PyObject_SetAttrString), Cint,
-                   (PyPtr, Cstring, PyPtr), o, s, PyObject(v))
+    ispynull(o) && throw(ArgumentError("assign of NULL PyObject"))
+    p = ccall((@pysym :PyObject_SetAttrString), Cint, (PyPtr, Cstring, PyPtr), o, s, PyObject(v))
+    if p == -1 && pyerr_occurred()
+        e = pyerror("PyObject_SetAttrString")
+        if PyPtr(e.T) != @pyglobalobjptr(:PyExc_AttributeError)
+            throw(e)
+        end
         pyerr_clear()
         throw(KeyError(s))
     end
-    o
+    return o
 end
 
 function getindex(o::PyObject, s::T) where T<:Union{Symbol, AbstractString}

test/runtests.jl

@@ -829,3 +829,26 @@ end
         @test py"bar2" == 2
     end
 end
+
+@testset "proper exception raised" begin
+    py"""
+    class A:
+        def __getattr__(self, name):
+            if name == "a":
+                raise ValueError(name)
+            else:
+                raise AttributeError()
+
+        def __setattr__(self, name, value):
+            if value == 0:
+                raise ValueError(value)
+            else:
+                raise AttributeError()
+    """
+    a = py"A"()
+    @test_throws PyCall.PyError a.a
+    @test_throws KeyError a.b
+
+    @test_throws PyCall.PyError a.a = 0
+    @test_throws KeyError a.a = 1
+end