Subject: bug#31903: 27.0.50; Server sockets with :nowait no longer work

From: Noam Postavsky <[email-masked]>
Date: Thu, 05 Jul 2018 20:13:14 -0400

tags 31903 + patch
quit

Eli Zaretskii <[email-masked]> writes:

>> From: Noam Postavsky <[email-masked]>
>> Date: Sun, 01 Jul 2018 11:48:45 -0400
>> Cc: Lars Ingebrigtsen <[email-masked]>, [email-masked]
>> 
>> Helmut Eller <[email-masked]> writes:
>> 
>> > I'm not sure whether :nowait is supposed to work with server sockets,
>> > but this used to work in Emacs 25.  Either way, the error message looks
>> > pretty wrong.
>> 
>> As far as I can tell, Emacs 25 just ignores :nowait when :server is
>> passed.  We could change Emacs 26 do that as well, or we just make the
>> error official but give a more a sensible error message when passed both
>> :nowait and :server.
>
> Unless someone protests within the next few days, I think I prefer the
> latter alternative.

Okay, here is the patch for that, I will push to emacs-26 in a few days.

>From a2ec0e58ab979b0a64a097ff0880cb7509d8aced Mon Sep 17 00:00:00 2001
From: Noam Postavsky <[email-masked]>
Date: Thu, 5 Jul 2018 19:37:28 -0400
Subject: [PATCH v1] Explicitly reject :server and :nowait (Bug#31903)

* src/process.c (Fmake_network_process): Explicitly check for and
signal an error when passed both :server and :nowait non-nil.  In
Emacs 25, :nowait would be ignored in this case, but as of Emacs 26.1
this gives an error, albeit an unclear one.  Also remove obsolete
comment regarding configurations lacking non-blocking mode, the
corresponding code was removed in 2012-11-17 "Assume POSIX 1003.1-1988
or later for fcntl.h."
---
 src/process.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/src/process.c b/src/process.c
index 7f6ea1261e..4d7a735652 100644
--- a/src/process.c
+++ b/src/process.c
@@ -3890,12 +3890,15 @@ failed) connections may be logged in the server process's buffer.
   filter = Fplist_get (contact, QCfilter);
   sentinel = Fplist_get (contact, QCsentinel);
   use_external_socket_p = Fplist_get (contact, QCuse_external_socket);
+  Lisp_Object server = Fplist_get (contact, QCserver);
+  bool nowait = !NILP (Fplist_get (contact, QCnowait));
 
+  if (!NILP (server) && nowait)
+    error ("`:server' is incompatible with `:nowait'");
   CHECK_STRING (name);
 
   /* :local ADDRESS or :remote ADDRESS */
-  tem = Fplist_get (contact, QCserver);
-  if (NILP (tem))
+  if (!NILP (server))
     address = Fplist_get (contact, QCremote);
   else
     address = Fplist_get (contact, QClocal);
@@ -4009,7 +4012,7 @@ failed) connections may be logged in the server process's buffer.
     }
 
 #ifdef HAVE_GETADDRINFO_A
-  if (!NILP (host) && !NILP (Fplist_get (contact, QCnowait)))
+  if (!NILP (host) && nowait)
     {
       ptrdiff_t hostlen = SBYTES (host);
       struct req
@@ -4154,20 +4157,13 @@ failed) connections may be logged in the server process's buffer.
 
   set_network_socket_coding_system (proc, host, service, name);
 
-  /* :server BOOL */
-  tem = Fplist_get (contact, QCserver);
-  if (!NILP (tem))
-    {
-      /* Don't support network sockets when non-blocking mode is
-	 not available, since a blocked Emacs is not useful.  */
-      p->is_server = true;
-      if (TYPE_RANGED_INTEGERP (int, tem))
-	p->backlog = XINT (tem);
-    }
+  /* :server QLEN */
+  p->is_server = !NILP (server);
+  if (TYPE_RANGED_INTEGERP (int, server))
+    p->backlog = XINT (server);
 
   /* :nowait BOOL */
-  if (!p->is_server && socktype != SOCK_DGRAM
-      && !NILP (Fplist_get (contact, QCnowait)))
+  if (!p->is_server && socktype != SOCK_DGRAM && nowait)
     p->is_non_blocking_client = true;
 
   bool postpone_connection = false;
-- 
2.11.0