Part of bug #1523610: fix miscalculation of buffer length.

Also add a guard against NULL in converttuple and add a test case
(that previously would have crashed).

Lib/test/test_getargs2.py

@@ -233,8 +233,25 @@ class LongLong_TestCase(unittest.TestCase):
 
         self.failUnlessEqual(VERY_LARGE & ULLONG_MAX, getargs_K(VERY_LARGE))
 
+
+class Tuple_TestCase(unittest.TestCase):
+    def test_tuple(self):
+        from _testcapi import getargs_tuple
+        
+        ret = getargs_tuple(1, (2, 3))
+        self.assertEquals(ret, (1,2,3))
+
+        # make sure invalid tuple arguments are handled correctly
+        class seq:
+            def __len__(self):
+                return 2
+            def __getitem__(self, n):
+                raise ValueError
+        self.assertRaises(TypeError, getargs_tuple, 1, seq())
+
+
 def test_main():
-    tests = [Signed_TestCase, Unsigned_TestCase]
+    tests = [Signed_TestCase, Unsigned_TestCase, Tuple_TestCase]
     try:
         from _testcapi import getargs_L, getargs_K
     except ImportError:

Modules/_testcapimodule.c

@@ -294,6 +294,16 @@ test_L_code(PyObject *self)
 
 #endif	/* ifdef HAVE_LONG_LONG */
 
+/* Test tuple argument processing */
+static PyObject *
+getargs_tuple(PyObject *self, PyObject *args)
+{
+	int a, b, c;
+	if (!PyArg_ParseTuple(args, "i(ii)", &a, &b, &c))
+		return NULL;
+	return Py_BuildValue("iii", a, b, c);
+}
+
 /* Functions to call PyArg_ParseTuple with integer format codes,
    and return the result.
 */
@@ -707,6 +717,7 @@ static PyMethodDef TestMethods[] = {
 	{"test_null_strings",	(PyCFunction)test_null_strings,	 METH_NOARGS},
 	{"test_string_from_format", (PyCFunction)test_string_from_format, METH_NOARGS},
 
+	{"getargs_tuple",	getargs_tuple,			 METH_VARARGS},
 	{"getargs_b",		getargs_b,			 METH_VARARGS},
 	{"getargs_B",		getargs_B,			 METH_VARARGS},
 	{"getargs_H",		getargs_H,			 METH_VARARGS},

Python/getargs.c

@@ -351,8 +351,8 @@ seterror(int iarg, const char *msg, int *levels, const char *fname,
 				      "argument %d", iarg);
 			i = 0;
 			p += strlen(p);
-			while (levels[i] > 0 && (int)(p-buf) < 220) {
+			while (levels[i] > 0 && i < 32 && (int)(p-buf) < 220) {
-				PyOS_snprintf(p, sizeof(buf) - (buf - p),
+				PyOS_snprintf(p, sizeof(buf) - (p - buf),
 					      ", item %d", levels[i]-1);
 				p += strlen(p);
 				i++;
@@ -439,6 +439,13 @@ converttuple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
 		char *msg;
 		PyObject *item;
 		item = PySequence_GetItem(arg, i);
+		if (item == NULL) {
+			PyErr_Clear();
+			levels[0] = i+1;
+			levels[1] = 0;
+			strncpy(msgbuf, "is not retrievable", bufsize);
+			return msgbuf;
+		}
 		msg = convertitem(item, &format, p_va, flags, levels+1, 
 				  msgbuf, bufsize, freelist);
 		/* PySequence_GetItem calls tp->sq_item, which INCREFs */
@@ -1509,6 +1516,7 @@ vgetargskeywords(PyObject *args, PyObject *keywords, const char *format,
 		else {
 			msg = skipitem(&format, p_va, flags);
 			if (msg) {
+				levels[0] = 0;
 				seterror(i+1, msg, levels, fname, message);
 				return cleanreturn(0, freelist);
 			}