When running the following script under bash-4.4.0 to bash-4.4.23 it
seems to fail erroneously on read.
set -x
set -o pipefail
shopt -s lastpipe
main() {
# Any input piped into while such that the condition
# succeeds at least once.
echo "x" | while read; do
echo | read # anything piped to read
sleep 0 # any non-builtin
done
}
main || echo "main failed"
This produces the xtrace:
+ set -o pipefail
+ shopt -s lastpipe
+ main
+ read
+ echo x
+ read
+ echo
+ sleep 0
+ read
+ echo 'main failed'
main failed
Under bash-4.3 and bash-5.0 the script does not output "main failed",
as expected.
I'm not sure if this is a known bug. One user on IRC reported finding
the same issue on debian stretch, but another could not reproduce the
issue for bash-4.4.12.
I have bisected the history of the devel git branch and found that the commit:
85ec0778f9d778e1820fb8c0e3e996f2d1103b45 commit bash-20150417 snapshot
introduces the issue.
Applying the attached patch to a bash-4.4.23 source tree produces an
interpreter which does not output "main failed" when running the
aforementioned script.
diff --git a/jobs.c b/jobs.c
index d69b8d8d..ec014d1f 100644
--- a/jobs.c
+++ b/jobs.c
@@ -1043,9 +1043,10 @@ delete_job (job_index, dflags)
if (temp == 0)
return;
- if ((dflags & DEL_NOBGPID) == 0 && (temp->flags & (J_ASYNC|J_FOREGROUND)) == J_ASYNC)
+ if ((dflags & DEL_NOBGPID) == 0)
{
proc = find_last_proc (job_index, 0);
+ /* Could do this just for J_ASYNC jobs, but we save all. */
if (proc)
bgp_add (proc->pid, process_exit_status (proc->status));
}