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From: Jim Porter <jporterbugs@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: larsi@gnus.org, 56025@debbugs.gnu.org,
	spwhitton@email.arizona.edu, kbrown@cornell.edu
Subject: bug#56025: 29.0.50; em-extpipe-test-2 times out on EMBA and Cygwin
Date: Sat, 25 Jun 2022 09:13:46 -0700	[thread overview]
Message-ID: <0a5b3d44-c475-941f-c35c-7470c14e6d7b@gmail.com> (raw)
In-Reply-To: <83y1xlb91y.fsf@gnu.org>

[-- Attachment #1: Type: text/plain, Size: 914 bytes --]

On 6/24/2022 10:34 PM, Eli Zaretskii wrote:
>> Cc: larsi@gnus.org, 56025@debbugs.gnu.org
>> From: Jim Porter <jporterbugs@gmail.com>
>> Date: Fri, 24 Jun 2022 16:03:13 -0700
>>
>> POSIX standard says[1] (thanks to Eliot Moss on the Cygwin mailing list
>> for citing this passage):
>>
>>     When [EOF is] received, all the bytes waiting to be read are
>>     immediately passed to the process without waiting for a <newline>, and
>>     the EOF is discarded. Thus, if there are no bytes waiting (that is,
>>     the EOF occurred at the beginning of a line), a byte count of zero
>>     shall be returned from the read(), representing an end-of-file
>>     indication.
> 
> Perhaps some reference to this should also be in the comments.

How about this patch? I added a reference to the specific section of the 
POSIX specification so that it's (hopefully) easy for people to look up 
if they need further details.

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From 8664e6f3dc9e40d1fae8a44dc4c444ab40510a18 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Fri, 24 Jun 2022 09:14:38 -0700
Subject: [PATCH] When closing an Eshell process target, send EOF three times

* lisp/eshell/esh-io.el (eshell-close-target): Send EOF 3 times.

* test/lisp/eshell/em-extpipe-tests.el (em-extpipe-tests--deftest):
Re-enable these tests on EMBA.

This patch is adapted by one from Ken Brown, who uncovered the reason
for this bug (bug#56025).
---
 lisp/eshell/esh-io.el                | 16 ++++++++++++++--
 test/lisp/eshell/em-extpipe-tests.el |  1 -
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/lisp/eshell/esh-io.el b/lisp/eshell/esh-io.el
index 3644c1a18b..c035890ddf 100644
--- a/lisp/eshell/esh-io.el
+++ b/lisp/eshell/esh-io.el
@@ -276,8 +276,20 @@ eshell-close-target
    ;; If we're redirecting to a process (via a pipe, or process
    ;; redirection), send it EOF so that it knows we're finished.
    ((eshell-processp target)
-    (if (eq (process-status target) 'run)
-	(process-send-eof target)))
+    ;; According to POSIX.1-2017, section 11.1.9, sending EOF causes
+    ;; all bytes waiting to be read to be sent to the process
+    ;; immediately.  Thus, if there are any bytes waiting, we need to
+    ;; send EOF twice: once to flush the buffer, and a second time to
+    ;; cause the next read() to return a size of 0, indicating
+    ;; end-of-file to the reading process.  However, some platforms
+    ;; (e.g. Solaris) actually require sending a *third* EOF.  Since
+    ;; sending extra EOFs while the process is running shouldn't break
+    ;; anything, we'll just send the maximum we'd ever need.  See
+    ;; bug#56025 for further details.
+    (let ((i 0))
+      (while (and (<= (cl-incf i) 3)
+                  (eq (process-status target) 'run))
+        (process-send-eof target))))
 
    ;; A plain function redirection needs no additional arguments
    ;; passed.
diff --git a/test/lisp/eshell/em-extpipe-tests.el b/test/lisp/eshell/em-extpipe-tests.el
index 3b84d763ac..29f5dc0551 100644
--- a/test/lisp/eshell/em-extpipe-tests.el
+++ b/test/lisp/eshell/em-extpipe-tests.el
@@ -71,7 +71,6 @@ em-extpipe-tests--deftest
        (skip-unless shell-file-name)
        (skip-unless shell-command-switch)
        (skip-unless (executable-find shell-file-name))
-       (skip-unless (not (getenv "EMACS_EMBA_CI")))
        (let ((input ,input))
          (with-temp-eshell ,@body)))))
 
-- 
2.25.1


  reply	other threads:[~2022-06-25 16:13 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-16 18:30 bug#56025: 29.0.50; em-extpipe-test-2 times out on EMBA and Cygwin Ken Brown
2022-06-16 19:30 ` Sean Whitton
2022-06-16 22:01   ` Ken Brown
2022-06-17 13:39     ` Ken Brown
2022-06-18  0:57       ` Sean Whitton
2022-06-18  2:07         ` Ken Brown
2022-06-18  2:35           ` Ken Brown
2022-06-18  3:50           ` Jim Porter
2022-06-18 17:52             ` Ken Brown
2022-06-18 19:02               ` Jim Porter
2022-06-18 20:51                 ` Ken Brown
2022-06-18 22:00                   ` Jim Porter
2022-06-18 23:46                     ` Sean Whitton
2022-06-19 16:02                     ` Ken Brown
2022-06-24  1:18                       ` Ken Brown
2022-06-24  4:40                         ` Sean Whitton
2022-06-24  6:07                         ` Eli Zaretskii
2022-06-24 16:53                           ` Jim Porter
2022-06-24 22:23                             ` Sean Whitton
2022-06-24 23:03                               ` Jim Porter
2022-06-25  5:34                                 ` Eli Zaretskii
2022-06-25 16:13                                   ` Jim Porter [this message]
2022-06-25 16:53                                     ` Eli Zaretskii
2022-06-26 16:27                                       ` Lars Ingebrigtsen
2022-06-26 17:12                                 ` Sean Whitton
2022-06-26 17:22                                   ` Jim Porter
2022-06-26 21:11                                     ` Sean Whitton
2022-06-27 13:25                                       ` Ken Brown
2022-06-27 15:51                                         ` Michael Albinus
2022-06-27 16:22                                           ` Ken Brown
2022-06-27 19:13                                             ` bug#56025: [EXT]Re: " Sean Whitton
2022-06-27 21:17                                               ` Ken Brown
2022-06-27 19:18                                         ` Jim Porter
2022-06-27 21:19                                           ` Ken Brown
2022-07-01  3:52                                             ` Jim Porter
2022-07-01  3:58                                               ` Jim Porter
2022-07-06 22:33                                               ` Ken Brown
2022-07-07  4:35                                                 ` Jim Porter
2022-07-07  4:42                                                   ` Jim Porter
2022-07-07 12:42                                                     ` Ken Brown
2022-07-17  2:35                                                       ` bug#56025: [WIP PATCH] " Jim Porter
2022-07-17  6:03                                                         ` Eli Zaretskii
2022-07-17 17:44                                                           ` Jim Porter
2022-07-17 18:26                                                             ` Eli Zaretskii
2022-07-17 18:51                                                               ` Jim Porter
2022-07-18  8:09                                                             ` Michael Albinus
2022-07-19  1:58                                                               ` Jim Porter
2022-07-19  7:59                                                                 ` Michael Albinus
2022-07-17 21:59                                                         ` Ken Brown
2022-07-18  5:26                                                           ` Jim Porter
2022-07-22  4:16                                                             ` bug#56025: [PATCH v2] " Jim Porter
2022-07-22 19:00                                                               ` Ken Brown
2022-07-24  4:05                                                                 ` Jim Porter
2022-07-24  5:19                                                                   ` bug#56025: [PATCH v3] " Jim Porter
2022-07-24  5:29                                                                     ` bug#56025: [PATCH v4] " Jim Porter
2022-07-24  9:08                                                                       ` Lars Ingebrigtsen
2022-07-24  9:48                                                                         ` Eli Zaretskii
2022-07-24 21:04                                                                         ` Ken Brown
2022-07-24  9:47                                                                       ` Eli Zaretskii
2022-07-24 17:36                                                                         ` bug#56025: [PATCH v5] " Jim Porter
2022-07-24 20:30                                                                           ` Ken Brown
2022-07-31  1:01                                                                             ` Jim Porter
2022-08-06  1:10                                                                               ` Jim Porter
2022-08-06 12:17                                                                                 ` Lars Ingebrigtsen

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