- Fix segfault with invalid coding.

- SF Bug #772896, unknown encoding results in MemoryError, which is not helpful

I will only backport the segfault fix.  I'll let Anthony decide if he wants
the other changes backported.  I will do the backport if asked.

Lib/test/bad_coding.py

+# -*- coding: uft-8 -*-

Lib/test/test_coding.py

+
+import test.test_support, unittest
+import os
+
+class CodingTest(unittest.TestCase):
+    def test_bad_coding(self):
+        module_name = 'bad_coding'
+        self.assertRaises(SyntaxError, __import__, 'test.' + module_name)
+
+        path = os.path.dirname(__file__)
+        filename = os.path.join(path, module_name + '.py')
+        fp = open(filename)
+        text = fp.read()
+        fp.close()
+        self.assertRaises(SyntaxError, compile, text, filename, 'exec')
+
+def test_main():
+    test.test_support.run_unittest(CodingTest)
+
+if __name__ == "__main__":
+    test_main()

Misc/NEWS

@@ -12,6 +12,10 @@ What's New in Python 2.5 alpha 1?
 Core and builtins
 -----------------
 
+- Fix segfault with invalid coding.
+
+- SF bug #772896: unknown encoding results in MemoryError.
+
 - All iterators now have a Boolean value of true.  Formerly, some iterators
   supported a __len__() method which evaluated to False when the iterator
   was empty.

Parser/parsetok.c

@@ -42,7 +42,7 @@ PyParser_ParseStringFlagsFilename(const char *s, const char *filename,
 	initerr(err_ret, filename);
 
 	if ((tok = PyTokenizer_FromString(s)) == NULL) {
-		err_ret->error = E_NOMEM;
+		err_ret->error = PyErr_Occurred() ? E_DECODE : E_NOMEM;
 		return NULL;
 	}
 

Parser/pgenmain.c

@@ -116,6 +116,13 @@ getgrammar(char *filename)
 	return g;
 }
 
+/* Can't happen in pgen */
+PyObject*
+PyErr_Occurred()
+{
+	return 0;
+}
+
 void
 Py_FatalError(const char *msg)
 {

Parser/tokenizer.c

@@ -603,8 +603,11 @@ decode_str(const char *str, struct tok_state *tok)
 	if (tok->enc != NULL) {
 		assert(utf8 == NULL);
 		utf8 = translate_into_utf8(str, tok->enc);
-		if (utf8 == NULL)
+		if (utf8 == NULL) {
+			PyErr_Format(PyExc_SyntaxError,
+				"unknown encoding: %s", tok->enc);
 			return NULL;
+		}
 		str = PyString_AsString(utf8);
 	}
 #endif

Python/pythonrun.c

@@ -1487,7 +1487,7 @@ err_input(perrdetail *err)
 			msg = "unknown decode error";
 		Py_DECREF(type);
 		Py_DECREF(value);
-		Py_DECREF(tb);
+		Py_XDECREF(tb);
 		break;
 	}
 	case E_LINECONT: