Fix Python 2 builtin tp_hash hashfunc closure regression when using "python:slot"

Closes https://github.com/swig/swig/issues/843

CHANGES.current

@@ -5,6 +5,11 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 3.0.11 (in progress)
 ============================
 
+2016-12-23: wsfulton
+            [Python] Fix builtin "python:slot" feature failing for tp_hash when using
+            hashfunc closure with a "Wrong type for hash function" for Python 2.
+            Issue https://github.com/swig/swig/issues/843
+
 2016-12-21: joequamt
             Changed generation of functions so that only functions
             that end in _set generate accessor functions rather than

Examples/test-suite/python/python_builtin_runme.py

@@ -12,10 +12,14 @@ if is_python_builtin():
   if h != h2:
     raise RuntimeError("default tp_hash not working")
 
-  # Test 1 for tp_hash
+  # Test 1a for tp_hash
   if hash(SimpleValue(222)) != 222:
     raise RuntimeError("tp_hash not working")
 
+  # Test 1b for tp_hash
+  if hash(SimpleValue2(333)) != 333:
+    raise RuntimeError("tp_hash not working")
+
   # Test 2 for tp_hash
   try:
     # Was incorrectly raising: SystemError: error return without exception set

Examples/test-suite/python_builtin.i

@@ -27,7 +27,7 @@ struct ValueStruct {
 };
 %}
 
-// Test 1 for tp_hash
+// Test 1a for tp_hash
 #if defined(SWIGPYTHON_BUILTIN)
 %feature("python:tp_hash") SimpleValue "SimpleValueHashFunction"
 #endif
@@ -55,6 +55,24 @@ hashfunc test_hashfunc_cast() {
 }
 %}
 
+// Test 1b for tp_hash
+#if defined(SWIGPYTHON_BUILTIN)
+%feature("python:slot", "tp_hash", functype="hashfunc") SimpleValue2::HashFunc;
+#endif
+
+%inline %{
+struct SimpleValue2 {
+  int value;
+  SimpleValue2(int value) : value(value) {}
+#if PY_VERSION_HEX >= 0x03020000
+  typedef Py_hash_t HashType;
+#else
+  typedef long HashType;
+#endif
+  HashType HashFunc() { return (HashType)value; }
+};
+%}
+
 // Test 2 for tp_hash
 #if defined(SWIGPYTHON_BUILTIN)
 %feature("python:slot", "tp_hash", functype="hashfunc") BadHashFunctionReturnType::bad_hash_function;

Lib/python/builtin.swg

@@ -13,6 +13,11 @@ SWIGINTERN Py_hash_t
 SWIG_PyNumber_AsPyHash(PyObject *obj) {
   Py_hash_t result = -1;
 #if PY_VERSION_HEX < 0x03020000
+#if PY_VERSION_HEX < 0x03000000
+  if (PyInt_Check(obj))
+    result = PyInt_AsLong(obj);
+  else
+#endif
   if (PyLong_Check(obj))
     result = PyLong_AsLong(obj);
 #else
@@ -21,7 +26,7 @@ SWIG_PyNumber_AsPyHash(PyObject *obj) {
 #endif
   else
     PyErr_Format(PyExc_TypeError, "Wrong type for hash function");
-  return result;
+  return PyErr_Occurred() ? -1 : result;
 }
 
 SWIGINTERN int