Revert previous two checkins to repair test failure.

The special-case code that was removed could return a value indicating
success but leave an exception set.  test_fileinput failed in a debug
build as a result.

diff --git a/Objects/listobject.c b/Objects/listobject.c
index c630f179e264389f8ec4736caa8abfd97b229ed2..c9e66044c71394594a4b32dd03980b6ced0b50e3 100644 (file)
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2234,13 +2234,6 @@ list_richcompare(PyObject *v, PyObject *w, int op)
        return PyObject_RichCompare(vl->ob_item[i], wl->ob_item[i], op);
 }
 
-/* empirically determined threshold for activating an optimisation
- * in list_fill() - 100 seems close to optimum for current CPUs and
- * compilers, as of December '03.
- * see also comment in list_fill().
- */
-#define        LISTFILL_OPT_THRESHOLD  100
-
 /* Adapted from newer code by Tim */
 static int
 list_fill(PyListObject *result, PyObject *v)
@@ -2255,23 +2248,12 @@ list_fill(PyListObject *result, PyObject *v)
 
        n = result->ob_size;
 
-       /* Special-case list(a_list), for speed:
-        * - if the source has 0 elements, there's nothing to copy.
-        * - if the source has more than a threshold number of elements
-        *   slice assignment is a faster way of filling the target
-        *   (the exact threshold is subject to empirical determination).
-        * Also special case any other zero length sequence, including
-        * subclasses of list, there being nothing to copy.
-        */
-       if (PyList_CheckExact(v)) {
-               i = PyList_GET_SIZE(v);
-               if (i == 0)
-                       return 0;
-               if (i > LISTFILL_OPT_THRESHOLD)
-                       return list_ass_slice(result, 0, n, v);
-       } else
-               if (PySequence_Check(v) && PySequence_Size(v) == 0)
-                       return 0;
+       /* Special-case list(a_list), for speed. */
+       if (PyList_Check(v)) {
+               if (v == (PyObject *)result)
+                       return 0; /* source is destination, we're done */
+               return list_ass_slice(result, 0, n, v);
+       }
 
        /* Empty previous contents */
        if (n != 0) {