Issue #8343: Named group error msgs did not show the group name.

Lib/sre_parse.py

@@ -567,7 +567,8 @@ def _parse(source, state):
                                         "%r" % name)
                         gid = state.groupdict.get(name)
                         if gid is None:
-                            raise error, "unknown group name"
+                            msg = "unknown group name: {0!r}".format(name)
+                            raise error(msg)
                         subpatternappend((GROUPREF, gid))
                         continue
                     else:
@@ -620,7 +621,8 @@ def _parse(source, state):
                     if isname(condname):
                         condgroup = state.groupdict.get(condname)
                         if condgroup is None:
-                            raise error, "unknown group name"
+                            msg = "unknown group name: {0!r}".format(condgroup)
+                            raise error(msg)
                     else:
                         try:
                             condgroup = int(condname)
@@ -746,7 +748,8 @@ def parse_template(source, pattern):
                     try:
                         index = pattern.groupindex[name]
                     except KeyError:
-                        raise IndexError, "unknown group name"
+                        msg = "unknown group name: {0!r}".format(name)
+                        raise IndexError(msg)
                 a((MARK, index))
             elif c == "0":
                 if s.next in OCTDIGITS:

Misc/NEWS

@@ -31,6 +31,9 @@ Library
 
 - Issue #21672: Fix the behavior of ntpath.join on UNC-style paths.
 
+- Issue #8343:  Named group error messages in the re module did not show
+  the name of the erroneous group.
+
 - Issue #21491: SocketServer: Fix a race condition in child processes reaping.
 
 - Issue #21635:  The difflib SequenceMatcher.get_matching_blocks() method