diff -r e948154af406 Lib/sre_parse.py
--- a/Lib/sre_parse.py	Sat Apr 13 18:00:04 2013 +0300
+++ b/Lib/sre_parse.py	Sat Apr 13 12:01:09 2013 -0400
@@ -588,7 +588,7 @@
                         if not name:
                             raise error("missing group name")
                         if not isname(name):
-                            raise error("bad character in group name")
+                            raise error("bad character in group name %r" % name)
                     elif sourcematch("="):
                         # named backreference
                         name = ""
@@ -602,7 +602,8 @@
                         if not name:
                             raise error("missing group name")
                         if not isname(name):
-                            raise error("bad character in group name")
+                            raise error("bad character in backref group name "
+                                        "%r" % name)
                         gid = state.groupdict.get(name)
                         if gid is None:
                             raise error("unknown group name")
diff -r e948154af406 Lib/test/test_re.py
--- a/Lib/test/test_re.py	Sat Apr 13 18:00:04 2013 +0300
+++ b/Lib/test/test_re.py	Sat Apr 13 12:01:09 2013 -0400
@@ -3,6 +3,7 @@
 import io
 import re
 from re import Scanner
+import sre_constants
 import sys
 import string
 import traceback
@@ -1021,6 +1022,16 @@
         self.assertRaises(OverflowError, re.compile, r".{,%d}" % MAXREPEAT)
         self.assertRaises(OverflowError, re.compile, r".{%d,}?" % MAXREPEAT)
 
+    def test_backref_group_name_in_exception(self):
+        # Issue 17341: Poor error message when compiling invalid regex
+        with self.assertRaisesRegexp(sre_constants.error, '<foo>'):
+            re.compile('(?P=<foo>)')
+
+    def test_group_name_in_exception(self):
+        # Issue 17341: Poor error message when compiling invalid regex
+        with self.assertRaisesRegexp(sre_constants.error, '\?foo'):
+            re.compile('(?P<?foo>)')
+
 
 def run_re_tests():
     from test.re_tests import tests, SUCCEED, FAIL, SYNTAX_ERROR
diff -r e948154af406 Misc/ACKS
--- a/Misc/ACKS	Sat Apr 13 18:00:04 2013 +0300
+++ b/Misc/ACKS	Sat Apr 13 12:01:09 2013 -0400
@@ -805,6 +805,7 @@
 Alexis Métaireau
 Steven Miale
 Trent Mick
+Jason Michalski
 Franck Michea
 Tom Middleton
 Stan Mihai