Re: Asynchronous DNS

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: a.s@realize.ch,  emacs-devel@gnu.org
> Date: Sun, 14 Feb 2016 18:01:39 +1100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Yes.  But AFAIU the suggestion to "add blockers" simply makes these
> > functions wait until the process is in that state.  So code that did
> > this outside of those functions will "just work" because these
> > blockers will become no-ops.
> 
> The issue is losing asynchronicity.  A function that previously called
> 
> (progn
>   (make-network-stream ... :nowait t)
>   (set-process-coding-system ...))
> 
> would not block.  With the proposed blockers (unless we add fine-grained
> code to all the process function to only block if we haven't even done
> DNS yet), this code will block.  And that's a regression.

If set-process-coding-system worked in the above snippet, it means it
doesn't need to block waiting for a fully capable process object.  If
it didn't work (as in signaled an error), then there's no regression.

> But, I mean, we could examine all these process functions and only have
> them block where we need them to, and things would work fine.

If the above snippet works now, you have already examined that
function, and you know what the conclusions are.