From: Tim Peters <tim.peters@gmail.com>
Date: Tue, 11 Sep 2001 01:41:59 +0000 (+0000)
Subject: More on SF bug [#460020] bug or feature: unicode() and subclasses.
X-Git-Tag: v2.2.1c1~1868
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=5a49ade70e19a76aa252cd596accf79930765f31;p=python

More on SF bug [#460020] bug or feature: unicode() and subclasses.
Repaired str(i) to return a genuine string when i is an instance of a str
subclass.  New PyString_CheckExact() macro.
---

diff --git a/Include/stringobject.h b/Include/stringobject.h
index a67e33e3a8..052eacf85e 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -52,6 +52,7 @@ typedef struct {
 extern DL_IMPORT(PyTypeObject) PyString_Type;
 
 #define PyString_Check(op) PyObject_TypeCheck(op, &PyString_Type)
+#define PyString_CheckExact(op) ((op)->ob_type == &PyString_Type)
 
 extern DL_IMPORT(PyObject *) PyString_FromStringAndSize(const char *, int);
 extern DL_IMPORT(PyObject *) PyString_FromString(const char *);
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index d756dc57d0..0de4dec078 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -1440,7 +1440,7 @@ def inherits():
         verify(u == s)
     s = madstring("12345")
     #XXX verify(str(s) == "12345")
-    #XXX verify(str(s).__class__ is str)
+    verify(str(s).__class__ is str)
 
     class madunicode(unicode):
         _rev = None
diff --git a/Objects/object.c b/Objects/object.c
index 704ffc13b2..718dddf7cf 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -250,10 +250,16 @@ PyObject_Str(PyObject *v)
 	
 	if (v == NULL)
 		return PyString_FromString("<NULL>");
-	if (PyString_Check(v)) {
+	if (PyString_CheckExact(v)) {
 		Py_INCREF(v);
 		return v;
 	}
+	if (PyString_Check(v)) {
+		/* For a string subtype that's not a string, return a true
+		   string with the same string data. */
+		PyStringObject *s = (PyStringObject *)v;
+		return PyString_FromStringAndSize(s->ob_sval, s->ob_size);
+	}
 	if (v->ob_type->tp_str == NULL)
 		return PyObject_Repr(v);
 
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 4c28500962..9c873ecc89 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -2711,7 +2711,7 @@ str_subtype_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 	tmp = string_new(&PyString_Type, args, kwds);
 	if (tmp == NULL)
 		return NULL;
-	assert(PyString_Check(tmp));
+	assert(PyString_CheckExact(tmp));
 	new = type->tp_alloc(type, n = PyString_GET_SIZE(tmp));
 	if (new != NULL)
 		memcpy(PyString_AS_STRING(new), PyString_AS_STRING(tmp), n+1);