Make identifiers str (not str8) objects throughout. This affects the parser, various object implementations, and all places that put identifiers into C string literals. In testing, a number of crashes occurred as code would fail when the recursion limit was reached (such as the Unicode interning dictionary having key/value pairs where key is not value). To solve these, I added an overflowed flag, which allows for 50 more recursions after the limit was reached and the exception was raised, and a recursion_critical flag, which indicates that recursion absolutely must be allowed, i.e. that a certain call must not cause a stack overflow exception. There are still some places where both str and str8 are accepted as identifiers; these should eventually be removed.

--- a/Python/sysmodule.c	Sat Jun 09 16:13:23 2007 +0000
+++ b/Python/sysmodule.c	Sun Jun 10 09:51:05 2007 +0000
@@ -280,7 +280,7 @@
 	int i;
 	for (i = 0; i < 7; ++i) {
 		if (whatstrings[i] == NULL) {
-			name = PyString_InternFromString(whatnames[i]);
+			name = PyUnicode_InternFromString(whatnames[i]);
 			if (name == NULL)
 				return -1;
 			whatstrings[i] = name;
@@ -801,7 +801,7 @@
 	if (list == NULL)
 		return NULL;
 	for (i = 0; PyImport_Inittab[i].name != NULL; i++) {
-		PyObject *name = PyString_FromString(
+		PyObject *name = PyUnicode_FromString(
 			PyImport_Inittab[i].name);
 		if (name == NULL)
 			break;