On Fri, Feb 05, 2021 at 05:25:59PM -0800, Paul Eggert wrote: > This fixes a longstanding glibc bug concerning backreferences > <https://sourceware.org/11053> (2009-12-04).
Nit: this short URL doesn't work, while the longer one does: https://sourceware.org/bugzilla/show_bug.cgi?id=11053 > * lib/regexec.c (proceed_next_node, push_fail_stack) > (pop_fail_stack): Push and pop the previous registers > as well as the current ones. All callers changed. > (set_regs): Also pop if CUR_NODE has already been checked, > so that it does not get added as a duplicate set entry. > (update_regs): Fix comment location. > * tests/test-regex.c (tests): New constant. > (bug_regex11): New test function. > (main): Bump alarm value. Call new test function. > --- > ChangeLog | 13 ++++++ > lib/regexec.c | 26 +++++++---- > tests/test-regex.c | 113 ++++++++++++++++++++++++++++++++++++++++++++- > 3 files changed, 141 insertions(+), 11 deletions(-) Apparently, this commit changes behaviour of GNU sed in a way that looks like regression. When GNU sed is built with this gnulib commit (v0.1-4426-g70b673eb7): $ echo 123 |sed -r 's/^1*+(.)/\1/' 3 $ echo 123 |sed -r 's/^(1*)*(.)/\2/' 3 When GNU sed is built with the previous gnulib commit (v0.1-4425-gf5596242f): $ echo 123 |sed -r 's/^1*+(.)/\1/' 23 $ echo 123 |sed -r 's/^(1*)*(.)/\2/' 23 There are regexps in the wild containing "*+" that used to work before, see e.g. https://lore.kernel.org/lkml/20210414182723.1670663-1...@altlinux.org/T/#u -- ldv
