bug#23864: 25.1.50; Poor network responsivenes using open-network-stream

[Paul Eggert <eggert@cs.ucla.edu>]

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On 06/30/2016 03:50 AM, Glenn Morris wrote:
> I see this is in emacs-25, so perhaps should be fixed there. 

I agree; it's a regression and the fix is small and localized. Thanks, 
Christer, for debugging and reporting this.

I installed the attached patch into master; it should have the same 
effect as Christer's patch but avoids some code duplication. I can 
backport it into the emacs-25 branch if there is no objection.

Ouch. Now I see that this patch has the wrong bug number (transposed 
digits) and attribution. Sorry about that. I will fix that for the 
backport, if we decide to install it into emacs-25.

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From 115b407d0816737357cf1923087a2651fcb99867 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sun, 3 Jul 2016 10:49:21 +0200
Subject: [PATCH] Fix open-network-stream responsiveness

Problem reported by Constantin Kulikov (Bug#23684).
* src/process.c (wait_reading_process_output):
Fix typo introduced in 2015-07-06T02:19:13Z!eggert@cs.ucla.edu
when wait == INFINITY and got_output_end_time is invalid.
In this case the code should break, not continue.
---
 src/process.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/process.c b/src/process.c
index ed0c529..376e872 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5269,16 +5269,20 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
              haven't lowered our timeout due to timers or SIGIO and
              have waited a long amount of time due to repeated
              timers.  */
+	  struct timespec cmp_time;
+	  bool have_cmp_time = false;
 	  if (wait < TIMEOUT)
 	    break;
-	  struct timespec cmp_time
-	    = (wait == TIMEOUT
-	       ? end_time
-	       : (!process_skipped && got_some_output > 0
-		  && (timeout.tv_sec > 0 || timeout.tv_nsec > 0))
-	       ? got_output_end_time
-	       : invalid_timespec ());
-	  if (timespec_valid_p (cmp_time))
+	  else if (wait == TIMEOUT)
+	    cmp_time = end_time, have_cmp_time = true;
+	  else if (!process_skipped && got_some_output > 0
+		   && (timeout.tv_sec > 0 || timeout.tv_nsec > 0))
+	    {
+	      if (!timespec_valid_p (got_output_end_time))
+		break;
+	      cmp_time = got_output_end_time, have_cmp_time = true;
+	    }
+	  if (have_cmp_time)
 	    {
 	      now = current_timespec ();
 	      if (timespec_cmp (cmp_time, now) <= 0)
-- 
2.5.5