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/Modules/_codecsmodule.c	Sat Jun 09 16:13:23 2007 +0000
+++ b/Modules/_codecsmodule.c	Sun Jun 10 09:51:05 2007 +0000
@@ -172,7 +172,7 @@
 			      &PyString_Type, &str, &errors))
 		return NULL;
 
-	size = PyUnicode_GET_SIZE(str);
+	size = PyString_GET_SIZE(str);
 	newsize = 4*size;
 	if (newsize > PY_SSIZE_T_MAX || newsize / 4 != size) {
 		PyErr_SetString(PyExc_OverflowError,