PEP 352 implementation. Creates a new base class, BaseException, which has an

added message attribute compared to the previous version of Exception.  It is
also a new-style class, making all exceptions now new-style.  KeyboardInterrupt
and SystemExit inherit from BaseException directly.  String exceptions now
raise DeprecationWarning.

Applies patch 1104669, and closes bugs 1012952 and 518846.

5 files changed, 300 insertions, 191 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 3ef853e..8d0f7e6 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1685,7 +1685,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throw)
 				    why == WHY_CONTINUE)
 					retval = POP();
 			}
-			else if (PyClass_Check(v) || PyString_Check(v)) {
+			else if (PyExceptionClass_Check(v) || PyString_Check(v)) {
 				w = POP();
 				u = POP();
 				PyErr_Restore(v, w, u);
@@ -3026,14 +3026,14 @@ do_raise(PyObject *type, PyObject *value, PyObject *tb)
 		/* Raising builtin string is deprecated but still allowed --
 		 * do nothing.  Raising an instance of a new-style str
 		 * subclass is right out. */
-		if (-1 == PyErr_Warn(PyExc_PendingDeprecationWarning,
+		if (PyErr_Warn(PyExc_DeprecationWarning,
 			   "raising a string exception is deprecated"))
 			goto raise_error;
 	}
-	else if (PyClass_Check(type))
+	else if (PyExceptionClass_Check(type))
 		PyErr_NormalizeException(&type, &value, &tb);
 
-	else if (PyInstance_Check(type)) {
+	else if (PyExceptionInstance_Check(type)) {
 		/* Raising an instance.  The value should be a dummy. */
 		if (value != Py_None) {
 			PyErr_SetString(PyExc_TypeError,
@@ -3044,7 +3044,7 @@ do_raise(PyObject *type, PyObject *value, PyObject *tb)
 			/* Normalize to raise <class>, <instance> */
 			Py_DECREF(value);
 			value = type;
-			type = (PyObject*) ((PyInstanceObject*)type)->in_class;
+			type = PyExceptionInstance_Class(type);
 			Py_INCREF(type);
 		}
 	}
diff --git a/Python/codecs.c b/Python/codecs.c
index cd31e1c..253bc39 100644
--- a/Python/codecs.c
+++ b/Python/codecs.c
@@ -448,9 +448,8 @@ static void wrong_exception_type(PyObject *exc)
 
 PyObject *PyCodec_StrictErrors(PyObject *exc)
 {
-    if (PyInstance_Check(exc))
-	PyErr_SetObject((PyObject*)((PyInstanceObject*)exc)->in_class,
-	    exc);
+    if (PyExceptionInstance_Check(exc))
+        PyErr_SetObject(PyExceptionInstance_Class(exc), exc);
     else
 	PyErr_SetString(PyExc_TypeError, "codec must pass exception instance");
     return NULL;
diff --git a/Python/errors.c b/Python/errors.c
index c33bd13..7fc4c97 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -97,11 +97,14 @@ PyErr_GivenExceptionMatches(PyObject *err, PyObject *exc)
 		return 0;
 	}
 	/* err might be an instance, so check its class. */
-	if (PyInstance_Check(err))
-		err = (PyObject*)((PyInstanceObject*)err)->in_class;
+	if (PyExceptionInstance_Check(err))
+		err = PyExceptionInstance_Class(err);
 
-	if (PyClass_Check(err) && PyClass_Check(exc))
-		return PyClass_IsSubclass(err, exc);
+	if (PyExceptionClass_Check(err) && PyExceptionClass_Check(exc)) {
+		/* problems here!?  not sure PyObject_IsSubclass expects to
+		   be called with an exception pending... */
+		return PyObject_IsSubclass(err, exc);
+	}
 
 	return err == exc;
 }
@@ -138,19 +141,19 @@ PyErr_NormalizeException(PyObject **exc, PyObject **val, PyObject **tb)
 		Py_INCREF(value);
 	}
 
-	if (PyInstance_Check(value))
-		inclass = (PyObject*)((PyInstanceObject*)value)->in_class;
+	if (PyExceptionInstance_Check(value))
+		inclass = PyExceptionInstance_Class(value);
 
 	/* Normalize the exception so that if the type is a class, the
 	   value will be an instance.
 	*/
-	if (PyClass_Check(type)) {
+	if (PyExceptionClass_Check(type)) {
 		/* if the value was not an instance, or is not an instance
 		   whose class is (or is derived from) type, then use the
 		   value as an argument to instantiation of the type
 		   class.
 		*/
-		if (!inclass || !PyClass_IsSubclass(inclass, type)) {
+		if (!inclass || !PyObject_IsSubclass(inclass, type)) {
 			PyObject *args, *res;
 
 			if (value == Py_None)
@@ -282,7 +285,7 @@ PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
 	{
 		/* Note that the Win32 errors do not lineup with the
 		   errno error.  So if the error is in the MSVC error
-		   table, we use it, otherwise we assume it really _is_ 
+		   table, we use it, otherwise we assume it really _is_
 		   a Win32 error code
 		*/
 		if (i > 0 && i < _sys_nerr) {
@@ -302,7 +305,7 @@ PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
 				0,	/* size not used */
 				NULL);	/* no args */
 			if (len==0) {
-				/* Only ever seen this in out-of-mem 
+				/* Only ever seen this in out-of-mem
 				   situations */
 				sprintf(s_small_buf, "Windows Error 0x%X", i);
 				s = s_small_buf;
@@ -345,8 +348,8 @@ PyErr_SetFromErrnoWithFilename(PyObject *exc, char *filename)
 PyObject *
 PyErr_SetFromErrnoWithUnicodeFilename(PyObject *exc, Py_UNICODE *filename)
 {
-	PyObject *name = filename ? 
-	                 PyUnicode_FromUnicode(filename, wcslen(filename)) : 
+	PyObject *name = filename ?
+	                 PyUnicode_FromUnicode(filename, wcslen(filename)) :
 	                 NULL;
 	PyObject *result = PyErr_SetFromErrnoWithFilenameObject(exc, name);
 	Py_XDECREF(name);
@@ -360,7 +363,7 @@ PyErr_SetFromErrno(PyObject *exc)
 	return PyErr_SetFromErrnoWithFilenameObject(exc, NULL);
 }
 
-#ifdef MS_WINDOWS 
+#ifdef MS_WINDOWS
 /* Windows specific error code handling */
 PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(
 	PyObject *exc,
@@ -415,8 +418,8 @@ PyObject *PyErr_SetExcFromWindowsErrWithFilename(
 	const char *filename)
 {
 	PyObject *name = filename ? PyString_FromString(filename) : NULL;
-	PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc, 
-	                                                             ierr, 
+	PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc,
+	                                                             ierr,
 	                                                             name);
 	Py_XDECREF(name);
 	return ret;
@@ -428,11 +431,11 @@ PyObject *PyErr_SetExcFromWindowsErrWithUnicodeFilename(
 	int ierr,
 	const Py_UNICODE *filename)
 {
-	PyObject *name = filename ? 
-	                 PyUnicode_FromUnicode(filename, wcslen(filename)) : 
+	PyObject *name = filename ?
+	                 PyUnicode_FromUnicode(filename, wcslen(filename)) :
 	                 NULL;
-	PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc, 
-	                                                             ierr, 
+	PyObject *ret = PyErr_SetExcFromWindowsErrWithFilenameObject(exc,
+	                                                             ierr,
 	                                                             name);
 	Py_XDECREF(name);
 	return ret;
@@ -466,8 +469,8 @@ PyObject *PyErr_SetFromWindowsErrWithUnicodeFilename(
 	int ierr,
 	const Py_UNICODE *filename)
 {
-	PyObject *name = filename ? 
-	                 PyUnicode_FromUnicode(filename, wcslen(filename)) : 
+	PyObject *name = filename ?
+	                 PyUnicode_FromUnicode(filename, wcslen(filename)) :
 	                 NULL;
 	PyObject *result = PyErr_SetExcFromWindowsErrWithFilenameObject(
 						      PyExc_WindowsError,
@@ -574,7 +577,24 @@ PyErr_WriteUnraisable(PyObject *obj)
 	if (f != NULL) {
 		PyFile_WriteString("Exception ", f);
 		if (t) {
-			PyFile_WriteObject(t, f, Py_PRINT_RAW);
+			char* className = PyExceptionClass_Name(t);
+			PyObject* moduleName =
+			      PyObject_GetAttrString(t, "__module__");
+
+			if (moduleName == NULL)
+				PyFile_WriteString("<unknown>", f);
+			else {
+				char* modstr = PyString_AsString(moduleName);
+				if (modstr)
+				{
+					PyFile_WriteString(modstr, f);
+					PyFile_WriteString(".", f);
+				}
+			}
+			if (className == NULL)
+				PyFile_WriteString("<unknown>", f);
+			else
+				PyFile_WriteString(className, f);
 			if (v && v != Py_None) {
 				PyFile_WriteString(": ", f);
 				PyFile_WriteObject(v, f, 0);
@@ -726,7 +746,7 @@ PyErr_SyntaxLocation(const char *filename, int lineno)
 
 /* com_fetch_program_text will attempt to load the line of text that
    the exception refers to.  If it fails, it will return NULL but will
-   not set an exception. 
+   not set an exception.
 
    XXX The functionality of this function is quite similar to the
    functionality in tb_displayline() in traceback.c.
diff --git a/Python/exceptions.c b/Python/exceptions.c
index c9e516f..59f2091 100644
--- a/Python/exceptions.c
+++ b/Python/exceptions.c
@@ -11,6 +11,7 @@
  * 98-08-19    fl   created (for pyexe)
  * 00-02-08    fl   updated for 1.5.2
  * 26-May-2000 baw  vetted for Python 1.6
+ * XXX
  *
  * written by Fredrik Lundh
  * modifications, additions, cleanups, and proofreading by Barry Warsaw
@@ -33,99 +34,19 @@
 PyDoc_STRVAR(module__doc__,
 "Python's standard exception class hierarchy.\n\
 \n\
-Before Python 1.5, the standard exceptions were all simple string objects.\n\
-In Python 1.5, the standard exceptions were converted to classes organized\n\
-into a relatively flat hierarchy.  String-based standard exceptions were\n\
-optional, or used as a fallback if some problem occurred while importing\n\
-the exception module.  With Python 1.6, optional string-based standard\n\
-exceptions were removed (along with the -X command line flag).\n\
-\n\
-The class exceptions were implemented in such a way as to be almost\n\
-completely backward compatible.  Some tricky uses of IOError could\n\
-potentially have broken, but by Python 1.6, all of these should have\n\
-been fixed.  As of Python 1.6, the class-based standard exceptions are\n\
-now implemented in C, and are guaranteed to exist in the Python\n\
-interpreter.\n\
-\n\
-Here is a rundown of the class hierarchy.  The classes found here are\n\
-inserted into both the exceptions module and the `built-in' module.  It is\n\
-recommended that user defined class based exceptions be derived from the\n\
-`Exception' class, although this is currently not enforced.\n"
+Exceptions found here are defined both in the exceptions module and the \n\
+built-in namespace.  It is recommended that user-defined exceptions inherit \n\
+from Exception.\n\
+"
+
 	/* keep string pieces "small" */
-"\n\
-Exception\n\
- |\n\
- +-- SystemExit\n\
- +-- StopIteration\n\
- +-- GeneratorExit\n\
- +-- StandardError\n\
- |    |\n\
- |    +-- KeyboardInterrupt\n\
- |    +-- ImportError\n\
- |    +-- EnvironmentError\n\
- |    |    |\n\
- |    |    +-- IOError\n\
- |    |    +-- OSError\n\
- |    |         |\n\
- |    |         +-- WindowsError\n\
- |    |         +-- VMSError\n\
- |    |\n\
- |    +-- EOFError\n\
- |    +-- RuntimeError\n\
- |    |    |\n\
- |    |    +-- NotImplementedError\n\
- |    |\n\
- |    +-- NameError\n\
- |    |    |\n\
- |    |    +-- UnboundLocalError\n\
- |    |\n\
- |    +-- AttributeError\n\
- |    +-- SyntaxError\n\
- |    |    |\n\
- |    |    +-- IndentationError\n\
- |    |         |\n\
- |    |         +-- TabError\n\
- |    |\n\
- |    +-- TypeError\n\
- |    +-- AssertionError\n\
- |    +-- LookupError\n\
- |    |    |\n\
- |    |    +-- IndexError\n\
- |    |    +-- KeyError\n\
- |    |\n\
- |    +-- ArithmeticError\n\
- |    |    |\n\
- |    |    +-- OverflowError\n\
- |    |    +-- ZeroDivisionError\n\
- |    |    +-- FloatingPointError\n\
- |    |\n\
- |    +-- ValueError\n\
- |    |    |\n\
- |    |    +-- UnicodeError\n\
- |    |        |\n\
- |    |        +-- UnicodeEncodeError\n\
- |    |        +-- UnicodeDecodeError\n\
- |    |        +-- UnicodeTranslateError\n\
- |    |\n\
- |    +-- ReferenceError\n\
- |    +-- SystemError\n\
- |    +-- MemoryError\n\
- |\n\
- +---Warning\n\
-      |\n\
-      +-- UserWarning\n\
-      +-- DeprecationWarning\n\
-      +-- PendingDeprecationWarning\n\
-      +-- SyntaxWarning\n\
-      +-- OverflowWarning\n\
-      +-- RuntimeWarning\n\
-      +-- FutureWarning"
+/* XXX exception hierarchy from Lib/test/exception_hierarchy.txt */
 );
 
 
 /* Helper function for populating a dictionary with method wrappers. */
 static int
-populate_methods(PyObject *klass, PyObject *dict, PyMethodDef *methods)
+populate_methods(PyObject *klass, PyMethodDef *methods)
 {
     PyObject *module;
     int status = -1;
@@ -151,7 +72,7 @@ populate_methods(PyObject *klass, PyObject *dict, PyMethodDef *methods)
 	}
 
 	/* add method to dictionary */
-	status = PyDict_SetItemString(dict, methods->ml_name, meth);
+	status = PyObject_SetAttrString(klass, methods->ml_name, meth);
 	Py_DECREF(meth);
 	Py_DECREF(func);
 
@@ -196,7 +117,7 @@ make_class(PyObject **klass, PyObject *base,
     if (!(*klass = PyErr_NewException(name, base, dict)))
 	goto finally;
 
-    if (populate_methods(*klass, dict, methods)) {
+    if (populate_methods(*klass, methods)) {
 	Py_DECREF(*klass);
 	*klass = NULL;
 	goto finally;
@@ -232,47 +153,81 @@ get_self(PyObject *args)
 /* Notes on bootstrapping the exception classes.
  *
  * First thing we create is the base class for all exceptions, called
- * appropriately enough: Exception.  Creation of this class makes no
+ * appropriately BaseException.  Creation of this class makes no
  * assumptions about the existence of any other exception class -- except
  * for TypeError, which can conditionally exist.
  *
- * Next, StandardError is created (which is quite simple) followed by
+ * Next, Exception is created since it is the common subclass for the rest of
+ * the needed exceptions for this bootstrapping to work.  StandardError is
+ * created (which is quite simple) followed by
  * TypeError, because the instantiation of other exceptions can potentially
  * throw a TypeError.  Once these exceptions are created, all the others
  * can be created in any order.  See the static exctable below for the
  * explicit bootstrap order.
  *
- * All classes after Exception can be created using PyErr_NewException().
+ * All classes after BaseException can be created using PyErr_NewException().
  */
 
-PyDoc_STRVAR(Exception__doc__, "Common base class for all exceptions.");
+PyDoc_STRVAR(BaseException__doc__, "Common base class for all exceptions");
 
+/*
+   Set args and message attributes.
 
-static PyObject *
-Exception__init__(PyObject *self, PyObject *args)
+   Assumes self and args have already been set properly with set_self, etc.
+*/
+static int
+set_args_and_message(PyObject *self, PyObject *args)
 {
-    int status;
+    PyObject *message_val;
+    Py_ssize_t args_len = PySequence_Length(args);
+
+    if (args_len < 0)
+	    return 0;
+
+    /* set args */
+    if (PyObject_SetAttrString(self, "args", args) < 0)
+	    return 0;
+
+    /* set message */
+    if (args_len == 1)
+	    message_val = PySequence_GetItem(args, 0);
+    else
+	    message_val = PyString_FromString("");
+    if (!message_val)
+	    return 0;
+
+    if (PyObject_SetAttrString(self, "message", message_val) < 0) {
+            Py_DECREF(message_val);
+            return 0;
+    }
+
+    Py_DECREF(message_val);
+    return 1;
+}
 
+static PyObject *
+BaseException__init__(PyObject *self, PyObject *args)
+{
     if (!(self = get_self(args)))
 	return NULL;
 
-    /* set args attribute */
-    /* XXX size is only a hint */
-    args = PySequence_GetSlice(args, 1, PySequence_Size(args));
+    /* set args and message attribute */
+    args = PySequence_GetSlice(args, 1, PySequence_Length(args));
     if (!args)
         return NULL;
-    status = PyObject_SetAttrString(self, "args", args);
-    Py_DECREF(args);
-    if (status < 0)
-        return NULL;
 
-    Py_INCREF(Py_None);
-    return Py_None;
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
+    }
+
+    Py_DECREF(args);
+    Py_RETURN_NONE;
 }
 
 
 static PyObject *
-Exception__str__(PyObject *self, PyObject *args)
+BaseException__str__(PyObject *self, PyObject *args)
 {
     PyObject *out;
 
@@ -310,9 +265,116 @@ Exception__str__(PyObject *self, PyObject *args)
     return out;
 }
 
+#ifdef Py_USING_UNICODE
+static PyObject *
+BaseException__unicode__(PyObject *self, PyObject *args)
+{
+	Py_ssize_t args_len;
+
+	if (!PyArg_ParseTuple(args, "O:__unicode__", &self))
+		return NULL;
+
+	args = PyObject_GetAttrString(self, "args");
+	if (!args)
+		return NULL;
+
+	args_len = PySequence_Size(args);
+	if (args_len < 0) {
+		Py_DECREF(args);
+		return NULL;
+	}
+
+	if (args_len == 0) {
+		Py_DECREF(args);
+		return PyUnicode_FromUnicode(NULL, 0);
+	}
+	else if (args_len == 1) {
+		PyObject *temp = PySequence_GetItem(args, 0);
+		if (!temp) {
+			Py_DECREF(args);
+			return NULL;
+		}
+		Py_DECREF(args);
+		return PyObject_Unicode(temp);
+	}
+	else {
+		Py_DECREF(args);
+		return PyObject_Unicode(args);
+	}
+}
+#endif /* Py_USING_UNICODE */
+
+static PyObject *
+BaseException__repr__(PyObject *self, PyObject *args)
+{
+	PyObject *args_attr;
+	Py_ssize_t args_len;
+	PyObject *repr_suffix;
+	PyObject *repr;
+	
+	if (!PyArg_ParseTuple(args, "O:__repr__", &self))
+		return NULL;
+
+	args_attr = PyObject_GetAttrString(self, "args");
+	if (!args_attr)
+		return NULL;
+
+	args_len = PySequence_Length(args_attr);
+	if (args_len < 0) {
+		Py_DECREF(args_attr);
+		return NULL;
+	}
+
+	if (args_len == 0) {
+		Py_DECREF(args_attr);
+		repr_suffix = PyString_FromString("()");
+		if (!repr_suffix)
+			return NULL;
+	}
+	else {
+		PyObject *args_repr;
+		/*PyObject *right_paren;
+
+		repr_suffix = PyString_FromString("(*");
+		if (!repr_suffix) {
+			Py_DECREF(args_attr);
+			return NULL;
+		}*/
+
+		args_repr = PyObject_Repr(args_attr);
+		Py_DECREF(args_attr);
+		if (!args_repr)
+			return NULL;
+
+		repr_suffix = args_repr;
+
+		/*PyString_ConcatAndDel(&repr_suffix, args_repr);
+		if (!repr_suffix)
+			return NULL;
+
+		right_paren = PyString_FromString(")");
+		if (!right_paren) {
+			Py_DECREF(repr_suffix);
+			return NULL;
+		}
+
+		PyString_ConcatAndDel(&repr_suffix, right_paren);
+		if (!repr_suffix)
+			return NULL;*/
+	}
+
+	repr = PyString_FromString(self->ob_type->tp_name);
+	if (!repr) {
+		Py_DECREF(repr_suffix);
+		return NULL;
+	}
+
+	PyString_ConcatAndDel(&repr, repr_suffix);
+	return repr;
+}
 
 static PyObject *
-Exception__getitem__(PyObject *self, PyObject *args)
+BaseException__getitem__(PyObject *self, PyObject *args)
 {
     PyObject *out;
     PyObject *index;
@@ -331,21 +393,27 @@ Exception__getitem__(PyObject *self, PyObject *args)
 
 
 static PyMethodDef
-Exception_methods[] = {
-    /* methods for the Exception class */
-    { "__getitem__", Exception__getitem__, METH_VARARGS},
-    { "__str__",     Exception__str__, METH_VARARGS},
-    { "__init__",    Exception__init__, METH_VARARGS},
-    { NULL, NULL }
+BaseException_methods[] = {
+    /* methods for the BaseException class */
+    {"__getitem__", BaseException__getitem__, METH_VARARGS},
+    {"__repr__", BaseException__repr__, METH_VARARGS},
+    {"__str__",     BaseException__str__, METH_VARARGS},
+#ifdef Py_USING_UNICODE
+    {"__unicode__",  BaseException__unicode__, METH_VARARGS},
+#endif /* Py_USING_UNICODE */
+    {"__init__",    BaseException__init__, METH_VARARGS},
+    {NULL, NULL }
 };
 
 
 static int
-make_Exception(char *modulename)
+make_BaseException(char *modulename)
 {
     PyObject *dict = PyDict_New();
     PyObject *str = NULL;
     PyObject *name = NULL;
+    PyObject *emptytuple = NULL;
+    PyObject *argstuple = NULL;
     int status = -1;
 
     if (!dict)
@@ -360,20 +428,28 @@ make_Exception(char *modulename)
     if (PyDict_SetItemString(dict, "__module__", str))
 	goto finally;
     Py_DECREF(str);
-    if (!(str = PyString_FromString(Exception__doc__)))
+
+    if (!(str = PyString_FromString(BaseException__doc__)))
 	goto finally;
     if (PyDict_SetItemString(dict, "__doc__", str))
 	goto finally;
 
-    if (!(name = PyString_FromString("Exception")))
+    if (!(name = PyString_FromString("BaseException")))
 	goto finally;
 
-    if (!(PyExc_Exception = PyClass_New(NULL, dict, name)))
+    if (!(emptytuple = PyTuple_New(0)))
+	goto finally;
+        
+    if (!(argstuple = PyTuple_Pack(3, name, emptytuple, dict)))
+	goto finally;
+       
+    if (!(PyExc_BaseException = PyType_Type.tp_new(&PyType_Type, argstuple,
+						       	NULL)))
 	goto finally;
 
     /* Now populate the dictionary with the method suite */
-    if (populate_methods(PyExc_Exception, dict, Exception_methods))
-	/* Don't need to reclaim PyExc_Exception here because that'll
+    if (populate_methods(PyExc_BaseException, BaseException_methods))
+	/* Don't need to reclaim PyExc_BaseException here because that'll
 	 * happen during interpreter shutdown.
 	 */
 	goto finally;
@@ -384,13 +460,18 @@ make_Exception(char *modulename)
     Py_XDECREF(dict);
     Py_XDECREF(str);
     Py_XDECREF(name);
+    Py_XDECREF(emptytuple);
+    Py_XDECREF(argstuple);
     return status;
 }
 
 
 
+PyDoc_STRVAR(Exception__doc__, "Common base class for all non-exit exceptions.");
+
 PyDoc_STRVAR(StandardError__doc__,
-"Base class for all standard Python exceptions.");
+"Base class for all standard Python exceptions that do not represent"
+"interpreter exiting.");
 
 PyDoc_STRVAR(TypeError__doc__, "Inappropriate argument type.");
 
@@ -411,14 +492,12 @@ SystemExit__init__(PyObject *self, PyObject *args)
     if (!(self = get_self(args)))
 	return NULL;
 
-    /* Set args attribute. */
     if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
         return NULL;
 
-    status = PyObject_SetAttrString(self, "args", args);
-    if (status < 0) {
-	Py_DECREF(args);
-        return NULL;
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
     }
 
     /* set code attribute */
@@ -445,8 +524,7 @@ SystemExit__init__(PyObject *self, PyObject *args)
     if (status < 0)
         return NULL;
 
-    Py_INCREF(Py_None);
-    return Py_None;
+    Py_RETURN_NONE;
 }
 
 
@@ -482,8 +560,12 @@ EnvironmentError__init__(PyObject *self, PyObject *args)
     if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
 	return NULL;
 
-    if (PyObject_SetAttrString(self, "args", args) ||
-	PyObject_SetAttrString(self, "errno", Py_None) ||
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
+    }
+
+    if (PyObject_SetAttrString(self, "errno", Py_None) ||
 	PyObject_SetAttrString(self, "strerror", Py_None) ||
 	PyObject_SetAttrString(self, "filename", Py_None))
     {
@@ -624,9 +706,9 @@ EnvironmentError__str__(PyObject *self, PyObject *args)
 	 *   return StandardError.__str__(self)
 	 *
 	 * but there is no StandardError__str__() function; we happen to
-	 * know that's just a pass through to Exception__str__().
+	 * know that's just a pass through to BaseException__str__().
 	 */
-	rtnval = Exception__str__(originalself, args);
+	rtnval = BaseException__str__(originalself, args);
 
   finally:
     Py_XDECREF(filename);
@@ -712,8 +794,10 @@ SyntaxError__init__(PyObject *self, PyObject *args)
     if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
 	return NULL;
 
-    if (PyObject_SetAttrString(self, "args", args))
-	goto finally;
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
+    }
 
     lenargs = PySequence_Size(args);
     if (lenargs >= 1) {
@@ -879,8 +963,9 @@ KeyError__str__(PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple(args, "O:__str__", &self))
 	return NULL;
 
-    if (!(argsattr = PyObject_GetAttrString(self, "args")))
-	return NULL;
+    argsattr = PyObject_GetAttrString(self, "args");
+    if (!argsattr)
+	    return NULL;
 
     /* If args is a tuple of exactly one item, apply repr to args[0].
        This is done so that e.g. the exception raised by {}[''] prints
@@ -889,14 +974,14 @@ KeyError__str__(PyObject *self, PyObject *args)
          KeyError
        alone.  The downside is that if KeyError is raised with an explanatory
        string, that string will be displayed in quotes.  Too bad.
-       If args is anything else, use the default Exception__str__().
+       If args is anything else, use the default BaseException__str__().
     */
     if (PyTuple_Check(argsattr) && PyTuple_GET_SIZE(argsattr) == 1) {
 	PyObject *key = PyTuple_GET_ITEM(argsattr, 0);
 	result = PyObject_Repr(key);
     }
     else
-	result = Exception__str__(self, args);
+	result = BaseException__str__(self, args);
 
     Py_DECREF(argsattr);
     return result;
@@ -1193,6 +1278,11 @@ UnicodeError__init__(PyObject *self, PyObject *args, PyTypeObject *objecttype)
     if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
 	return NULL;
 
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
+    }
+
     if (!PyArg_ParseTuple(args, "O!O!O!O!O!",
 	&PyString_Type, &encoding,
 	objecttype, &object,
@@ -1201,9 +1291,6 @@ UnicodeError__init__(PyObject *self, PyObject *args, PyTypeObject *objecttype)
 	&PyString_Type, &reason))
 	goto finally;
 
-    if (PyObject_SetAttrString(self, "args", args))
-	goto finally;
-
     if (PyObject_SetAttrString(self, "encoding", encoding))
 	goto finally;
     if (PyObject_SetAttrString(self, "object", object))
@@ -1405,6 +1492,11 @@ UnicodeTranslateError__init__(PyObject *self, PyObject *args)
     if (!(args = PySequence_GetSlice(args, 1, PySequence_Size(args))))
 	return NULL;
 
+    if (!set_args_and_message(self, args)) {
+	    Py_DECREF(args);
+	    return NULL;
+    }
+
     if (!PyArg_ParseTuple(args, "O!O!O!O!",
 	&PyUnicode_Type, &object,
 	&PyInt_Type, &start,
@@ -1412,9 +1504,6 @@ UnicodeTranslateError__init__(PyObject *self, PyObject *args)
 	&PyString_Type, &reason))
 	goto finally;
 
-    if (PyObject_SetAttrString(self, "args", args))
-	goto finally;
-
     if (PyObject_SetAttrString(self, "object", object))
 	goto finally;
     if (PyObject_SetAttrString(self, "start", start))
@@ -1424,8 +1513,8 @@ UnicodeTranslateError__init__(PyObject *self, PyObject *args)
     if (PyObject_SetAttrString(self, "reason", reason))
 	goto finally;
 
-    Py_INCREF(Py_None);
     rtnval = Py_None;
+    Py_INCREF(rtnval);
 
   finally:
     Py_DECREF(args);
@@ -1591,6 +1680,7 @@ static PyMethodDef functions[] = {
 
 /* Global C API defined exceptions */
 
+PyObject *PyExc_BaseException;
 PyObject *PyExc_Exception;
 PyObject *PyExc_StopIteration;
 PyObject *PyExc_GeneratorExit;
@@ -1636,7 +1726,7 @@ PyObject *PyExc_VMSError;
 #endif
 
 /* Pre-computed MemoryError instance.  Best to create this as early as
- * possibly and not wait until a MemoryError is actually raised!
+ * possible and not wait until a MemoryError is actually raised!
  */
 PyObject *PyExc_MemoryErrorInst;
 
@@ -1663,9 +1753,10 @@ static struct {
     int (*classinit)(PyObject *);
 } exctable[] = {
  /*
-  * The first three classes MUST appear in exactly this order
+  * The first four classes MUST appear in exactly this order
   */
- {"Exception", &PyExc_Exception},
+ {"BaseException", &PyExc_BaseException},
+ {"Exception", &PyExc_Exception, &PyExc_BaseException, Exception__doc__},
  {"StopIteration", &PyExc_StopIteration, &PyExc_Exception,
   StopIteration__doc__},
  {"GeneratorExit", &PyExc_GeneratorExit, &PyExc_Exception,
@@ -1676,9 +1767,10 @@ static struct {
  /*
   * The rest appear in depth-first order of the hierarchy
   */
- {"SystemExit", &PyExc_SystemExit, &PyExc_Exception, SystemExit__doc__,
+ {"SystemExit", &PyExc_SystemExit, &PyExc_BaseException, SystemExit__doc__,
   SystemExit_methods},
- {"KeyboardInterrupt",  &PyExc_KeyboardInterrupt, 0, KeyboardInterrupt__doc__},
+ {"KeyboardInterrupt",  &PyExc_KeyboardInterrupt, &PyExc_BaseException,
+	 KeyboardInterrupt__doc__},
  {"ImportError",        &PyExc_ImportError,       0, ImportError__doc__},
  {"EnvironmentError",   &PyExc_EnvironmentError,  0, EnvironmentError__doc__,
   EnvironmentError_methods},
@@ -1786,11 +1878,11 @@ _PyExc_Init(void)
     }
 
     /* This is the base class of all exceptions, so make it first. */
-    if (make_Exception(modulename) ||
-	PyDict_SetItemString(mydict, "Exception", PyExc_Exception) ||
-	PyDict_SetItemString(bdict, "Exception", PyExc_Exception))
+    if (make_BaseException(modulename) ||
+	PyDict_SetItemString(mydict, "BaseException", PyExc_BaseException) ||
+	PyDict_SetItemString(bdict, "BaseException", PyExc_BaseException))
     {
-	Py_FatalError("Base class `Exception' could not be created.");
+	Py_FatalError("Base class `BaseException' could not be created.");
     }
 
     /* Now we can programmatically create all the remaining exceptions.
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index d5c86f2..bbe9352 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -976,7 +976,7 @@ handle_system_exit(void)
 	fflush(stdout);
 	if (value == NULL || value == Py_None)
 		goto done;
-	if (PyInstance_Check(value)) {
+	if (PyExceptionInstance_Check(value)) {
 		/* The error code should be in the `code' attribute. */
 		PyObject *code = PyObject_GetAttrString(value, "code");
 		if (code) {
@@ -1106,11 +1106,10 @@ void PyErr_Display(PyObject *exception, PyObject *value, PyObject *tb)
 		if (err) {
 			/* Don't do anything else */
 		}
-		else if (PyClass_Check(exception)) {
-			PyClassObject* exc = (PyClassObject*)exception;
-			PyObject* className = exc->cl_name;
+		else if (PyExceptionClass_Check(exception)) {
+			char* className = PyExceptionClass_Name(exception);
 			PyObject* moduleName =
-			      PyDict_GetItemString(exc->cl_dict, "__module__");
+			      PyObject_GetAttrString(exception, "__module__");
 
 			if (moduleName == NULL)
 				err = PyFile_WriteString("<unknown>", f);
@@ -1126,8 +1125,7 @@ void PyErr_Display(PyObject *exception, PyObject *value, PyObject *tb)
 				if (className == NULL)
 				      err = PyFile_WriteString("<unknown>", f);
 				else
-				      err = PyFile_WriteObject(className, f,
-							       Py_PRINT_RAW);
+				      err = PyFile_WriteString(className, f);
 			}
 		}
 		else