Merged revisions 78603 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

........
  r78603 | victor.stinner | 2010-03-03 00:20:02 +0100 (mer., 03 mars 2010) | 5 lines

  Issue #7820: The parser tokenizer restores all bytes in the right if the BOM
  check fails.

  Fix an assertion in pydebug mode.
........
diff --git a/Lib/test/test_pep263.py b/Lib/test/test_pep263.py
index 8c1fbe7..e136a9c 100644
--- a/Lib/test/test_pep263.py
+++ b/Lib/test/test_pep263.py
@@ -44,6 +44,17 @@
         self.assertEqual(len(d['a']), len(d['b']))
         self.assertEqual(ascii(d['a']), ascii(d['b']))
 
+    def test_issue7820(self):
+        # Ensure that check_bom() restores all bytes in the right order if
+        # check_bom() fails in pydebug mode: a buffer starts with the first
+        # byte of a valid BOM, but next bytes are different
+
+        # one byte in common with the UTF-16-LE BOM
+        self.assertRaises(SyntaxError, eval, b'\xff\x20')
+
+        # two bytes in common with the UTF-8 BOM
+        self.assertRaises(SyntaxError, eval, b'\xef\xbb\x20')
+
 def test_main():
     support.run_unittest(PEP263Test)