Re: bug-report: debug trap messes up pipestatus if containing command substitution

[Hengyang Zhao]

+speng004@ucr.edu +yunduan.han@gmail.com

On Mon, May 20, 2019 at 9:51 PM Hengyang Zhao <hzhao877502@gmail.com> wrote:

> Dear bash developers,
>
> I found an unexpected behavior when engineering some code in a callback of
> DEBUG trap. The code has been distilled to expose this behavior:
>
> ### BEGIN
> my_func() {
>   local x=$(:)
> }
> trap my_func DEBUG
> false | true | false | true | false
> echo ${PIPESTATUS[@]}
> # expects 1 0 1 0 1
> # gets 0 0 0 0 1
> ### END
>
> Configuration Information:
> Machine: x86_64
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS: -O2 -g -pipe -Wall -Werror=format-security
> -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
> -fstack-protector-strong -grecord-gcc-switches
> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
> -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
> -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection
> -Wno-parentheses -Wno-format-security
> uname output: Linux fedora 5.0.9-301.fc30.x86_64 #1 SMP Tue Apr 23
> 23:57:35 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
> Machine Type: x86_64-redhat-linux-gnu
>
> This also happens on many of my OSes running bash 4.x.
>
> I'm happy to provide further information if needed.
>
> Thank you,
> Hengyang
>