Michael Hudson <mwh21@cam.ac.uk>:

Removed PyErr_BadArgument() calls and replaced them with more useful
error messages.

Modules/arraymodule.c

@@ -540,7 +540,9 @@ array_concat(a, bb)
 	int size;
 	arrayobject *np;
 	if (!is_arrayobject(bb)) {
-		PyErr_BadArgument();
+		PyErr_Format(PyExc_TypeError,
+		     "can only append array (not \"%.200s\") to array",
+			     bb->ob_type->tp_name);
 		return NULL;
 	}
 #define b ((arrayobject *)bb)
@@ -613,7 +615,9 @@ array_ass_slice(a, ilow, ihigh, v)
 		}
 	}
 	else {
-		PyErr_BadArgument();
+		PyErr_Format(PyExc_TypeError,
+	     "can only assign array (not \"%.200s\") to array slice",
+			     v->ob_type->tp_name);
 		return -1;
 	}
 	if (ilow < 0)
@@ -821,7 +825,8 @@ array_reverse(self, args)
 	char tmp[sizeof(double)]; /* Assume that's the max item size */
 
 	if (args != NULL) {
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError,
+		     "<array>.reverse requires exactly 0 arguments");
 		return NULL;
 	}
 

Modules/posixmodule.c

@@ -1562,8 +1562,7 @@ posix_spawnv(self, args)
 		getitem = PyTuple_GetItem;
 	}
 	else {
- badarg:
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError, "argv must be tuple or list");
 		return NULL;
 	}
 
@@ -1573,7 +1572,9 @@ posix_spawnv(self, args)
 	for (i = 0; i < argc; i++) {
 		if (!PyArg_Parse((*getitem)(argv, i), "s", &argvlist[i])) {
 			PyMem_DEL(argvlist);
-			goto badarg;
+			PyErr_SetString(PyExc_TypeError, 
+					"all arguments must be strings");
+			return NULL;
 		}
 	}
 	argvlist[argc] = NULL;

Modules/structmodule.c

@@ -1128,7 +1128,8 @@ struct_pack(self, args)
 	if (args == NULL || !PyTuple_Check(args) ||
 	    (n = PyTuple_Size(args)) < 1)
         {
-		PyErr_BadArgument();
+		PyErr_SetString(PyExc_TypeError, 
+			"struct.pack requires at least one argument");
 		return NULL;
 	}
 	format = PyTuple_GetItem(args, 0);