[Python-checkins] cpython (merge 3.5 -> default): Issue #24580: Symbolic group references to open group in re patterns now are

[serhiy.storchaka]

https://hg.python.org/cpython/rev/4d3557500019
changeset:   96950:4d3557500019
parent:      96948:adc9869c6d0d
parent:      96949:361d7af9396e
user:        Serhiy Storchaka <storchaka at gmail.com>
date:        Sat Jul 18 23:37:31 2015 +0300
summary:
  Issue #24580: Symbolic group references to open group in re patterns now are
explicitly forbidden as well as numeric group references.

files:
  Lib/sre_parse.py    |  3 +++
  Lib/test/test_re.py |  2 ++
  Misc/NEWS           |  3 +++
  3 files changed, 8 insertions(+), 0 deletions(-)


diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -675,6 +675,9 @@
                         if gid is None:
                             msg = "unknown group name %r" % name
                             raise source.error(msg, len(name) + 1)
+                        if not state.checkgroup(gid):
+                            raise source.error("cannot refer to an open group",
+                                               len(name) + 1)
                         state.checklookbehindgroup(gid, source)
                         subpatternappend((GROUPREF, gid))
                         continue
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -224,6 +224,8 @@
         self.checkPatternError('(?P<a>)(?P<a>)',
                                "redefinition of group name 'a' as group 2; "
                                "was group 1")
+        self.checkPatternError('(?P<a>(?P=a))',
+                               "cannot refer to an open group", 10)
         self.checkPatternError('(?Pxy)', 'unknown extension ?Px')
         self.checkPatternError('(?P<a>)(?P=a', 'missing ), unterminated name', 11)
         self.checkPatternError('(?P=', 'missing group name', 4)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -41,6 +41,9 @@
 Library
 -------
 
+- Issue #24580: Symbolic group references to open group in re patterns now are
+  explicitly forbidden as well as numeric group references.
+
 - Issue #24206: Fixed __eq__ and __ne__ methods of inspect classes.
 
 - Issue #24631: Fixed regression in the timeit module with multiline setup.

-- 
Repository URL: https://hg.python.org/cpython