Re: Feature request: ZSH_XTRACEFD variable

[Stephane Chazelas <stephane@xxxxxxxxxxxx>]

2020-05-03 00:06:58 +0000, Daniel Shahaf:
[...]
> P.S. Shouldn't ZSH_XTRACEFD be declared with PM_DONTIMPORT?

(assuming PM_DONTIMPORT is about not importing it from the
environment)

ZSH_XTRACEFD is useful in things like:

ZSH_XTRACEFD=7 zsh -x myscript 7> somefile

Or

ZSH_XTRACEFD=7 zsh -lx 7> somefile

to debug start-up file issues.

That's the primary way I've been using its bash counterpart.
See
https://unix.stackexchange.com/search?q=user%3A22565+BASH_XTRACEFD
for several examples.

bash also allows

SHELLOPTS=xtrace BASH_XTRACEFD=7 some-command

Which will cause all bash invocations run through some-command
(including those running as sh!) to have their xtrace option
set. I've used that to debug things like grub-install.

I don't think we want to go there with zsh. With zsh, one can
always add a:

if [[ -n $MYDEBUG ]]; then
  ZSH_XTRACEFD=7
  set -o xtrace
fi

to their ~/.zshenv to enable this kind of debugging.

-- 
Stephane