bug#62004: 30.0.50; comp-run-async-workers failure when default-directory deleted

[No Wayman <iarchivedmywholelife@gmail.com>]

>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> > Well, maybe we should bind the variable to be on the safe 
>> > side?  What
>> > if we bind it to the directory where we write that
>> > emacs-async-comp-something.el file?

Binding default-directory makes sense.
It's just a matter of what to bind it to.
I see that `comp-run-async-workers` calls `make-temp-file' 
internally.
Binding default-directory to temporary-file-directory around the 
call to `make-process' will prevent this error and seems like a 
safe bet.

>> From: Andrea Corallo <akrl@sdf.org>
>> Cc: iarchivedmywholelife@gmail.com, 62004@debbugs.gnu.org
>> Date: Tue, 07 Mar 2023 13:51:37 +0000
>>
>> Maybe but the reporter says "The default-directory is dependent 
>> on where
>> comp-run-async-workers happens to kick off." and I don't 
>> understand if
>> that's correct why is that.
>> 
>> I'd like first to understand better the issue here.
>
> I agree that we should first have a good understanding of the
> situation.  Let me know if I can help in any way.

The call to `make-process' in `comp-run-async-workers' is executed 
in the context of whatever default-directory happens to be. If 
default-directory does not refer to an existing directory (as 
demonstrated in the reproduction case I provided) the creation of 
the subprocess will fail.
I'm not sure what more detail I can provide, so please ask a 
specific question if you have any.