Index: Lib/test/test_array.py
===================================================================
--- Lib/test/test_array.py	(.../p3yk)	(revision 53047)
+++ Lib/test/test_array.py	(.../p3yk-noslice)	(revision 53047)
@@ -455,6 +455,18 @@
             array.array(self.typecode)
         )
 
+    def test_extended_getslice(self):
+        # Test extended slicing by comparing with list slicing
+        # (Assumes list conversion works correctly, too)
+        a = array.array(self.typecode, self.example)
+        indices = (0, None, 1, 3, 19, 100, -1, -2, -31, -100)
+        for start in indices:
+            for stop in indices:
+                # Everything except the initial 0 (invalid step)
+                for step in indices[1:]:
+                    self.assertEqual(list(a[start:stop:step]),
+                                     list(a)[start:stop:step])
+        
     def test_setslice(self):
         a = array.array(self.typecode, self.example)
         a[:1] = a
@@ -538,12 +550,34 @@
 
         a = array.array(self.typecode, self.example)
         self.assertRaises(TypeError, a.__setslice__, 0, 0, None)
+        self.assertRaises(TypeError, a.__setitem__, slice(0, 0), None)
         self.assertRaises(TypeError, a.__setitem__, slice(0, 1), None)
 
         b = array.array(self.badtypecode())
         self.assertRaises(TypeError, a.__setslice__, 0, 0, b)
+        self.assertRaises(TypeError, a.__setitem__, slice(0, 0), b)
         self.assertRaises(TypeError, a.__setitem__, slice(0, 1), b)
 
+    def test_extended_set_del_slice(self):
+        indices = (0, None, 1, 3, 19, 100, -1, -2, -31, -100)
+        for start in indices:
+            for stop in indices:
+                # Everything except the initial 0 (invalid step)
+                for step in indices[1:]:
+                    a = array.array(self.typecode, self.example)
+                    L = list(a)
+                    # Make sure we have a slice of exactly the right length,
+                    # but with (hopefully) different data.
+                    data = L[start:stop:step]
+                    data.reverse()
+                    L[start:stop:step] = data
+                    a[start:stop:step] = array.array(self.typecode, data)
+                    self.assertEquals(a, array.array(self.typecode, L))
+                    
+                    del L[start:stop:step]
+                    del a[start:stop:step]
+                    self.assertEquals(a, array.array(self.typecode, L))
+
     def test_index(self):
         example = 2*self.example
         a = array.array(self.typecode, example)
Index: Modules/arraymodule.c
===================================================================
--- Modules/arraymodule.c	(.../p3yk)	(revision 53047)
+++ Modules/arraymodule.c	(.../p3yk-noslice)	(revision 53047)
@@ -1582,7 +1582,12 @@
 		}
 		if (i < 0)
 			i += self->ob_size;
-		return array_item(self, i);
+		if (i < 0 || i >= self->ob_size) {
+			PyErr_SetString(PyExc_IndexError,
+				"array index out of range");
+			return NULL;
+		}
+		return getarrayitem((PyObject *)self, i);
 	}
 	else if (PySlice_Check(item)) {
 		Py_ssize_t start, stop, step, slicelength, cur, i;
@@ -1598,6 +1603,16 @@
 		if (slicelength <= 0) {
 			return newarrayobject(&Arraytype, 0, self->ob_descr);
 		}
+		else if (step == 1) {
+			PyObject *result = newarrayobject(&Arraytype,
+						slicelength, self->ob_descr);
+			if (result == NULL)
+				return NULL;
+			memcpy(((arrayobject *)result)->ob_item,
+			       self->ob_item + start * itemsize,
+			       slicelength * itemsize);
+			return result;
+		}
 		else {
 			result = newarrayobject(&Arraytype, slicelength, self->ob_descr);
 			if (!result) return NULL;
@@ -1616,7 +1631,7 @@
 	}
 	else {
 		PyErr_SetString(PyExc_TypeError, 
-				"list indices must be integers");
+				"array indices must be integers");
 		return NULL;
 	}
 }
@@ -1624,111 +1639,145 @@
 static int
 array_ass_subscr(arrayobject* self, PyObject* item, PyObject* value)
 {
+	Py_ssize_t start, stop, step, slicelength, needed;
+	arrayobject* other;
+	int itemsize;
+
 	if (PyIndex_Check(item)) {
 		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
-		if (i==-1 && PyErr_Occurred()) 
+		
+		if (i == -1 && PyErr_Occurred())
 			return -1;
 		if (i < 0)
 			i += self->ob_size;
-		return array_ass_item(self, i, value);
+		if (i < 0 || i >= self->ob_size) {
+			PyErr_SetString(PyExc_IndexError,
+				"array assignment index out of range");
+			return -1;
+		}
+		if (value == NULL) {
+			/* Fall through to slice assignment */
+			start = i;
+			stop = i + 1;
+			step = 1;
+			slicelength = 1;
+		}
+		else
+			return (*self->ob_descr->setitem)(self, i, value);
 	}
 	else if (PySlice_Check(item)) {
-		Py_ssize_t start, stop, step, slicelength;
-		int itemsize = self->ob_descr->itemsize;
-
-		if (PySlice_GetIndicesEx((PySliceObject*)item, self->ob_size,
-				 &start, &stop, &step, &slicelength) < 0) {
+		if (PySlice_GetIndicesEx((PySliceObject *)item,
+					 self->ob_size, &start, &stop,
+					 &step, &slicelength) < 0) {
 			return -1;
 		}
-
-		/* treat A[slice(a,b)] = v _exactly_ like A[a:b] = v */
-		if (step == 1 && ((PySliceObject*)item)->step == Py_None)
-			return array_ass_slice(self, start, stop, value);
-
-		if (value == NULL) {
-			/* delete slice */
-			Py_ssize_t cur, i, extra;
-			
-			if (slicelength <= 0)
-				return 0;
-
-			if (step < 0) {
-				stop = start + 1;
-				start = stop + step*(slicelength - 1) - 1;
-				step = -step;
-			}
-
-			for (cur = start, i = 0; i < slicelength - 1;
-			     cur += step, i++) {
-				memmove(self->ob_item + (cur - i)*itemsize,
-					self->ob_item + (cur + 1)*itemsize,
-					(step - 1) * itemsize);
-			}
-			extra = self->ob_size - (cur + 1);
-			if (extra > 0) {
-				memmove(self->ob_item + (cur - i)*itemsize,
-					self->ob_item + (cur + 1)*itemsize,
-					extra*itemsize);
-			}
-
-			self->ob_size -= slicelength;
-			self->ob_item = (char *)PyMem_REALLOC(self->ob_item,
-							      itemsize*self->ob_size);
-			self->allocated = self->ob_size;
-
-			return 0;
+	}
+	else {
+		PyErr_SetString(PyExc_TypeError,
+				"array indices must be integer");
+		return -1;
+	}
+	if (value == NULL) {
+		other = NULL;
+		needed = 0;
+	}
+	else if (array_Check(value)) {
+		other = (arrayobject *)value;
+		needed = other->ob_size;
+		if (self == other) {
+			/* Special case "self[i:j] = self" -- copy self first */
+			int ret;
+			value = array_slice(other, 0, needed);
+			if (value == NULL)
+				return -1;
+			ret = array_ass_subscr(self, item, value);
+			Py_DECREF(value);
+			return ret;
 		}
-		else {
-			/* assign slice */
-			Py_ssize_t cur, i;
-			arrayobject* av;
-
-			if (!array_Check(value)) {
-				PyErr_Format(PyExc_TypeError,
-			     "must assign array (not \"%.200s\") to slice",
-					     value->ob_type->tp_name);
+		if (other->ob_descr != self->ob_descr) {
+			PyErr_BadArgument();
+			return -1;
+		}
+	}
+	else {
+		PyErr_Format(PyExc_TypeError,
+	     "can only assign array (not \"%.200s\") to array slice",
+			     value->ob_type->tp_name);
+		return -1;
+	}
+	itemsize = self->ob_descr->itemsize;
+	/* for 'a[2:1] = ...', the insertion point is 'start', not 'stop' */
+	if ((step > 0 && stop < start) ||
+	    (step < 0 && stop > start))
+		stop = start;
+	if (step == 1) {
+		if (slicelength > needed) {
+			memmove(self->ob_item + (start + needed) * itemsize,
+				self->ob_item + stop * itemsize,
+				(self->ob_size - stop) * itemsize);
+			if (array_resize(self, self->ob_size +
+					 needed - slicelength) < 0)
 				return -1;
-			}
-
-			av = (arrayobject*)value;
-
-			if (av->ob_size != slicelength) {
-				PyErr_Format(PyExc_ValueError,
-            "attempt to assign array of size %ld to extended slice of size %ld",
-					     /*XXX*/(long)av->ob_size, /*XXX*/(long)slicelength);
+		}
+		else if (slicelength < needed) {
+			if (array_resize(self, self->ob_size +
+					 needed - slicelength) < 0)
 				return -1;
-			}
+			memmove(self->ob_item + (start + needed) * itemsize,
+				self->ob_item + stop * itemsize,
+				(self->ob_size - start - needed) * itemsize);
+		}
+		if (needed > 0)
+			memcpy(self->ob_item + start * itemsize,
+			       other->ob_item, needed * itemsize);
+		return 0;
+	}
+	else if (needed == 0) {
+		/* Delete slice */
+		Py_ssize_t cur, i;
+		
+		if (step < 0) {
+			stop = start + 1;
+			start = stop + step * (slicelength - 1) - 1;
+			step = -step;
+		}
+		for (cur = start, i = 0; i < slicelength;
+		     cur += step, i++) {
+			Py_ssize_t lim = step - 1;
 
-			if (!slicelength)
-				return 0;
+			if (cur + step >= self->ob_size)
+				lim = self->ob_size - cur - 1;
+			memmove(self->ob_item + (cur - i) * itemsize,
+				self->ob_item + (cur + 1) * itemsize,
+				lim * itemsize);
+		}
+		cur = start + slicelength * step;
+		if (cur < self->ob_size) {
+			memmove(self->ob_item + (cur-slicelength) * itemsize,
+				self->ob_item + cur * itemsize,
+				(self->ob_size - cur) * itemsize);
+		}
+		if (array_resize(self, self->ob_size - slicelength) < 0)
+			return -1;
+		return 0;
+	}
+	else {
+		Py_ssize_t cur, i;
 
-			/* protect against a[::-1] = a */
-			if (self == av) { 
-				value = array_slice(av, 0, av->ob_size);
-				av = (arrayobject*)value;
-				if (!av)
-					return -1;
-			} 
-			else {
-				Py_INCREF(value);
-			}
-
-			for (cur = start, i = 0; i < slicelength; 
-			     cur += step, i++) {
-				memcpy(self->ob_item + cur*itemsize,
-				       av->ob_item + i*itemsize,
-				       itemsize);
-			}
-
-			Py_DECREF(value);
-			
-			return 0;
+		if (needed != slicelength) {
+			PyErr_Format(PyExc_ValueError,
+				"attempt to assign array of size %zd "
+				"to extended slice of size %zd",
+				needed, slicelength);
+			return -1;
 		}
-	} 
-	else {
-		PyErr_SetString(PyExc_TypeError, 
-				"list indices must be integers");
-		return -1;
+		for (cur = start, i = 0; i < slicelength;
+		     cur += step, i++) {
+			memcpy(self->ob_item + cur * itemsize,
+			       other->ob_item + i * itemsize,
+			       itemsize);
+		}
+		return 0;
 	}
 }