Re: [v2 PATCH] trap: Preserve parent traps for trap-only command substitution

[Jilles Tjoelker <jilles@xxxxxxxx>]

On Mon, Apr 15, 2024 at 06:17:36PM +0800, Herbert Xu wrote:
> v2 restricts the preservation to command substitution only and
> only if the command's first word is "trap".

> ---8<---
> Traps are reset when a subshell is started.  When a subshell is
> started for command substitution with a simple command whose first
> word is "trap", preserve the parent trap text so that they can be
> printed.

It looks like this will execute the EXIT trap in a subshell $(trap).

On the other hand, things like $(trap "echo subshell exit >&2" EXIT) and
$(trap "echo other trap >&2" USR1) seem to be handled correctly.

I think the intent of https://austingroupbugs.net/view.php?id=53 is that
things like $('trap') and $(\trap) should also work (although an
expansion that expands to trap need not work).

-- 
Jilles Tjoelker