Fix for SF bug #117241

When a method is called with no regular arguments and * args, defer
the first arg is subclass check until after the * args have been
expanded.

N.B. The CALL_FUNCTION implementation is getting really hairy; should
review it to see if it can be simplified.

Lib/test/test_extcall.py

@@ -144,3 +144,21 @@ for i in range(512):
     d[key] = i
 a, b = f2(1, *(2, 3), **d)
 print len(a), len(b), b == d
+
+class Foo:
+    def method(self, arg1, arg2):
+        return arg1 + arg2
+
+x = Foo()
+print Foo.method(*(x, 1, 2))
+print Foo.method(x, *(1, 2))
+try:
+    print Foo.method(*(1, 2, 3))
+except TypeError, err:
+    print err
+try:
+    print Foo.method(1, *(2, 3))
+except TypeError, err:
+    print err
+
+

Python/ceval.c

@@ -1822,7 +1822,7 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			    na++;
 			    n++;
 			}
-			else {
+			else if (!((flags & 1) && na == 0)) {
 			    /* Unbound methods must be called with an
 			       instance of the class (or a derived
 			       class) as first argument */ 
@@ -1895,6 +1895,20 @@ eval_code2(PyCodeObject *co, PyObject *globals, PyObject *locals,
 			    if (nstar < 0) {
 				goto extcall_fail;
 			    }
+			    if (class && self == NULL && na == 0) {
+				/* * arg is first argument of method,
+				   so check it is isinstance of class */
+				self = PyTuple_GET_ITEM(stararg, 0);
+				if (!(PyInstance_Check(self) &&
+				      PyClass_IsSubclass((PyObject *)
+				   (((PyInstanceObject *)self)->in_class),
+							 class))) {
+				    PyErr_SetString(PyExc_TypeError,
+	    "unbound method must be called with instance as first argument");
+				    x = NULL;
+				    break;
+				}
+			    }
 			}
 			if (nk > 0) {
 			    if (kwdict == NULL) {