Add test for pop_fail_stack bug

Problem reported by Hanno Böck in: http://bugs.gnu.org/21513
If you use --with-included-regex the bug fix is in gnulib, here:
http://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=5513b40999149090987a0341c018d05d3eea1272
If you use glibc, the bug fix has not been installed yet.
* tests/Makefile.am (XFAIL_TESTS): Add backref-alt if system matcher.
(TESTS): Add backref-alt.
* tests/backref-alt: New file.
* tests/triple-backref: Remove unused var.
Don't skip if tested with glibc, as Makefile.am now handles this.

1 files changed, 27 insertions, 0 deletions

diff --git a/tests/backref-alt b/tests/backref-alt
new file mode 100755
index 00000000..d6a8f2e7
--- /dev/null
+++ b/tests/backref-alt
@@ -0,0 +1,27 @@
+#! /bin/sh
+# Test for a bug in glibc's regex code as of 2015-09-19.
+#
+# Copyright 2015 Free Software Foundation, Inc.
+#
+# Copying and distribution of this file, with or without modification,
+# are permitted in any medium without royalty provided the copyright
+# notice and this notice are preserved.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+echo aa > in || framework_failure_
+
+fail=0
+
+grep -E 'b|(.)b|\1|b' in >out
+status=$?
+# POSIX isn’t clear whether this regular expression should be invalid,
+# (because the \1 is out of range for REs that could precede it)
+# or valid but \1 should not match.  Allow either interpretation.
+test $status -eq 2 || test $status -eq 1 || fail=1
+
+grep -E '0|()0|\1|0' in >out
+status=$?
+test $status -eq 2 || test $status -eq 1 || fail=1
+
+Exit $fail