On 6/10/26 8:12 AM, Alex Chernyakhovsky wrote:
Dear maintainer,I believe I have found a regression in bash when using subshells with set -e. I discovered this while looking through the logs of mirrors.mit.edu's sync jobs, and noticed that despite `set -e`, the script did not terminate when rsync returned non-zero. In case it is relevant, the sync scripts are available at https://github.com/sipb/mirrors-sync; fetch-hudson is the entry point, and ubuntu-archive is the one that I noticed triggered the behavior. Here's the minimized test case: ``` $ cat harness.sh <(echo '---') helper #!/bin/bash set -e echo "Sourcing helper" (. helper) && : echo "Helper exited with $?"
In this script, set -e is ignored in the subshell because the subshell is part of an AND-OR list. Even turning it on in the subshell has no effect. The current version of the man page puts it this way: "If a compound command or shell function executes in a context where -e is being ignored, none of the commands executed within the compound command or function body will be affected by the -e setting, even if -e is set and a command returns a failure status. If a compound command or shell function sets -e while executing in a context where -e is ignored, that setting will not have any effect until the compound command or the command containing the function call completes."
I also double-checked the behavior against dash (0.5.12-12 from Debian Trixie), and dash acts like bash 4.2 and older: ``` $ dash harness.sh Sourcing helper In helper Helper exited with 1 ```
Behavior varies; dash has chosen an interpretation that I don't believe is conformant. yash and ksh93, for instance, behave like bash.
I believe that bash's current behavior goes against the POSIX specification if my reading of https://pubs.opengroup.org/onlinepubs/9799919799/utilities/V3_chap02.html is correct.
We had a long austin-group discussion about this back in 2009, and I
believe the current bash behavior reflects that discussion.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU [email protected] http://tiswww.cwru.edu/~chet/
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