To reproduce: printf '%s\n' hello '' world | sed -n -e 's/^//' -e '$!N' -e P -e D Expected output: hello world Actual output: hello h world
This is reproducible on -current. The output of GNU sed: $ printf '%s\n' hello '' world | gsed -n -e 's/^//' -e '$!N' -e P -e D hello world
Note that this issue also happens on OpenBSD 7.5, but not on NetBSD 10.0.
The issue was introduced with a patch from OpenBSD - https://svnweb.freebsd.org/base?view=revision&revision=299211 I've submitted a patch to OpenBSD to fix the issue there, and the same can be brought here - https://marc.info/?l=openbsd-tech&m=172381888706699&w=2
Created attachment 253175 [details] fix
The patch has been merged to OpenBSD: - https://github.com/openbsd/src/commit/01c98acc9b4c00302167d987e61d873d0abe9b30 - https://github.com/openbsd/src/commit/141b108e00b06c20bfa9167f6faaa9419dbb87c4
Could someone please merge this fix and the one in bug #271817? These fixes are already in OpenBSD and NetBSD, respectively. Thanks.
A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=5982237f1e5a30b6b7d67b307b4d3685b00718bf commit 5982237f1e5a30b6b7d67b307b4d3685b00718bf Author: Mohamed Akram <mohd.akram@outlook.com> AuthorDate: 2024-12-23 19:06:09 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2024-12-23 19:07:14 +0000 sed: Fix handling of an empty pattern space Add a regression test. PR: 271791 Obtained from: OpenBSD (1.38 millert) MFC after: 2 weeks usr.bin/sed/process.c | 10 ++++------ usr.bin/sed/tests/sed2_test.sh | 14 ++++++++++++++ 2 files changed, 18 insertions(+), 6 deletions(-)
A commit in branch stable/14 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=2c1c6bd7d5dbddd953587c1f003e6164749e087b commit 2c1c6bd7d5dbddd953587c1f003e6164749e087b Author: Mohamed Akram <mohd.akram@outlook.com> AuthorDate: 2024-12-23 19:06:09 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2025-01-14 14:14:24 +0000 sed: Fix handling of an empty pattern space Add a regression test. PR: 271791 Obtained from: OpenBSD (1.38 millert) MFC after: 2 weeks (cherry picked from commit 5982237f1e5a30b6b7d67b307b4d3685b00718bf) usr.bin/sed/process.c | 10 ++++------ usr.bin/sed/tests/sed2_test.sh | 14 ++++++++++++++ 2 files changed, 18 insertions(+), 6 deletions(-)
A commit in branch stable/13 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=91af1b8001d34a1563d861f1da81deaa121adca8 commit 91af1b8001d34a1563d861f1da81deaa121adca8 Author: Mohamed Akram <mohd.akram@outlook.com> AuthorDate: 2024-12-23 19:06:09 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2025-01-14 14:43:05 +0000 sed: Fix handling of an empty pattern space Add a regression test. PR: 271791 Obtained from: OpenBSD (1.38 millert) MFC after: 2 weeks (cherry picked from commit 5982237f1e5a30b6b7d67b307b4d3685b00718bf) usr.bin/sed/process.c | 10 ++++------ usr.bin/sed/tests/sed2_test.sh | 14 ++++++++++++++ 2 files changed, 18 insertions(+), 6 deletions(-)
Thank you for the report.