bug#33050: 27.0.50; [macOS] Problem with process input with process-connection-type nil

[Thomas Fitzsimmons]

Filipp Gunbin <fgunbin@fastmail.fm> writes:

> On 26/10/2018 22:09 -0400, Thomas Fitzsimmons wrote:
>
>> (I also wonder what happens to a process (e.g., Bash) that needs a pty,
>> when all ptys are busy.  I haven't done any experiments to check.  At
>> least in one case I saw in the source code, ange-ftp.el, the program
>> would just hang in pipe mode.  In that case, it seems like there should
>> be a way to tell start-process to signal an error if it doesn't get the
>> desired pty.)
>
> Yes, would be good to check this.

I tested ldapsearch after setting the maximum number of ptys to the
number of currently-busy ptys:

cat /proc/sys/kernel/pty/nr > /proc/sys/kernel/pty/max

It does get run in pipe mode silently (i.e., no warning messages are
generated), and as we already confirmed, ldapsearch happens to still
work when run in pipe mode.

>>> Your suggestion to condionally fix this for Darwin on release looks
>>> good.
>>
>> OK, can you try the attached patch before I push it to emacs-26?
>
> I tried it on emacs-26, and couldn't get eudc-expand-inline to work, but
> I think that's a different unrelated problem (maybe auth-source reading
> .authinfo or something).  Otherwise it looks safe.  I can look more into
> it on Monday..

OK, I guess file another bug if there's another issue preventing
eudc-expand-inline from working on emacs-26.

Thanks,
Thomas