bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[J.P.]

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Tags: patch

Knowing when we're reconnecting and having that logic be as sane and
straightforward as possible is (IMO) a critical component of unraveling
the buffer-association game I've been trying to drag everyone into.

The existing approach is troublesome because it's basically inscrutable
in the sense of being too difficult to sit down and reason through once
session identities enter the fray (at least for a simpleton like me).
And though the solution I'm proposing may seem underwhelming, it wasn't
just intuited out of thin air but rather discovered with the backing of
behavioral tests like the ones included in these patches [1]. Thanks.


[1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=48598
    https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49860


In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.17.4)
 of 2021-08-09 built on localhost
Repository revision: aeec97fae0ccfcc4dc406a5e0e4c0a94b834cac4
Repository branch: master
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[-- Attachment #2: 0001-Normalize-usage-of-variable-erc-server-reconnecting.patch --]
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From 8ee467d08e00db22309e363aaf1cdd8e3bfe15b5 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Fri, 11 Jun 2021 03:55:07 -0700
Subject: [PATCH] Normalize usage of variable erc-server-reconnecting

* lisp/erc/erc-backend.el (erc-server-reconnecting-p):
Don't consider erc-server-reconnecting when rendering verdict.
(erc-process-sentinel-2): ensure local variable
erc-server-reconnecting is t when timers are scheduled or running and
trying to reconnect, and nil otherwise, including after no retries
remain. Previously, its use and meaning in erc-backend were convoluted
and conflicted with its use in erc-cmd-RECONNECT.
---
 lisp/erc/erc-backend.el | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/lisp/erc/erc-backend.el b/lisp/erc/erc-backend.el
index 6d84665873..1836b7a51c 100644
--- a/lisp/erc/erc-backend.el
+++ b/lisp/erc/erc-backend.el
@@ -197,8 +197,7 @@ erc-server-quitting
   "Non-nil if the user requests a quit.")
 
 (defvar-local erc-server-reconnecting nil
-  "Non-nil if the user requests an explicit reconnect, and the
-current IRC process is still alive.")
+  "Non-nil if reconnecting or scheduled to.")
 
 (defvar-local erc-server-timed-out nil
   "Non-nil if the IRC server failed to respond to a ping.")
@@ -618,36 +617,34 @@ erc-server-filter-function
             (erc-log-irc-protocol line nil)
             (erc-parse-server-response process line)))))))
 
-(define-inline erc-server-reconnect-p (event)
+(defun erc--server-reconnect-p (event)
   "Return non-nil if ERC should attempt to reconnect automatically.
 EVENT is the message received from the closed connection process."
-  (inline-letevals (event)
-    (inline-quote
-     (or erc-server-reconnecting
-         (and erc-server-auto-reconnect
-              (not erc-server-banned)
-              ;; make sure we don't infinitely try to reconnect, unless the
-              ;; user wants that
-              (or (eq erc-server-reconnect-attempts t)
-                  (and (integerp erc-server-reconnect-attempts)
-                       (< erc-server-reconnect-count
-                          erc-server-reconnect-attempts)))
-              (or erc-server-timed-out
-                  (not (string-match "^deleted" ,event)))
-              ;; open-network-stream-nowait error for connection refused
-              (if (string-match "^failed with code 111" ,event) 'nonblocking t))))))
+  (and erc-server-auto-reconnect
+       (not erc-server-banned)
+       ;; make sure we don't infinitely try to reconnect, unless the
+       ;; user wants that
+       (or (eq erc-server-reconnect-attempts t)
+           (and (integerp erc-server-reconnect-attempts)
+                (< erc-server-reconnect-count
+                   erc-server-reconnect-attempts)))
+       (or erc-server-timed-out
+           (not (string-match "^deleted" event)))
+       ;; open-network-stream-nowait error for connection refused
+       (if (string-match "^failed with code 111" event) 'nonblocking t)))
 
 (defun erc-process-sentinel-2 (event buffer)
   "Called when `erc-process-sentinel-1' has detected an unexpected disconnect."
   (if (not (buffer-live-p buffer))
       (erc-update-mode-line)
     (with-current-buffer buffer
-      (let ((reconnect-p (erc-server-reconnect-p event)) message delay)
+      (let ((reconnect-p (erc--server-reconnect-p event)) message delay)
         (setq message (if reconnect-p 'disconnected 'disconnected-noreconnect))
         (erc-display-message nil 'error (current-buffer) message)
         (if (not reconnect-p)
             ;; terminate, do not reconnect
             (progn
+              (setq erc-server-reconnecting nil)
               (erc-display-message nil 'error (current-buffer)
                                    'terminated ?e event)
               ;; Update mode line indicators
@@ -656,7 +653,7 @@ erc-process-sentinel-2
           ;; reconnect
           (condition-case nil
               (progn
-                (setq erc-server-reconnecting   nil
+                (setq erc-server-reconnecting t
                       erc-server-reconnect-count (1+ erc-server-reconnect-count))
                 (setq delay erc-server-reconnect-timeout)
                 (run-at-time delay nil
-- 
2.31.1

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[Stefan Kangas]

"J.P." <jp@neverwas.me> writes:

> Tags: patch
>
> Knowing when we're reconnecting and having that logic be as sane and
> straightforward as possible is (IMO) a critical component of unraveling
> the buffer-association game I've been trying to drag everyone into.
>
> The existing approach is troublesome because it's basically inscrutable
> in the sense of being too difficult to sit down and reason through once
> session identities enter the fray (at least for a simpleton like me).
> And though the solution I'm proposing may seem underwhelming, it wasn't
> just intuited out of thin air but rather discovered with the backing of
> behavioral tests like the ones included in these patches [1]. Thanks.
>
>
> [1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=48598
>     https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49860

Copying in the ERC maintainer Amin Bandali here.

Amin, could you help review this patch?

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[Amin Bandali]

Hi Stefan, all,

Stefan Kangas writes:

> "J.P." <jp@neverwas.me> writes:
>
>> Tags: patch
>>
>> Knowing when we're reconnecting and having that logic be as sane and
>> straightforward as possible is (IMO) a critical component of unraveling
>> the buffer-association game I've been trying to drag everyone into.
>>
>> The existing approach is troublesome because it's basically inscrutable
>> in the sense of being too difficult to sit down and reason through once
>> session identities enter the fray (at least for a simpleton like me).
>> And though the solution I'm proposing may seem underwhelming, it wasn't
>> just intuited out of thin air but rather discovered with the backing of
>> behavioral tests like the ones included in these patches [1]. Thanks.
>>
>>
>> [1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=48598
>>     https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49860
>
> Copying in the ERC maintainer Amin Bandali here.
>
> Amin, could you help review this patch?

I will review this patch -- and the other two you tagged me on -- but
most likely not before emacs-28 is cut: per J.P.[0] the tests covering
these three patches live in another, rather large, patch and I would
prefer to leave the merging of these to after the other large patch is
reviewed and merged (which may not be until a few more weeks).

[0]: https://lists.gnu.org/r/emacs-erc/2021-09/msg00004.html

Of course if you're volunteering to help test/review the large
patch(es) and these three that would be very welcome. :)

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[Lars Ingebrigtsen]

"J.P." <jp@neverwas.me> writes:

> Subject: [PATCH] Normalize usage of variable erc-server-reconnecting

I think I managed to follow the logic of this change, and it doesn't
seem to regress anything after a bit of testing, so I've pushed it to
Emacs 29.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[J.P.]

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Lars Ingebrigtsen <larsi@gnus.org> writes:

> "J.P." <jp@neverwas.me> writes:
>
>> Subject: [PATCH] Normalize usage of variable erc-server-reconnecting
>
> I think I managed to follow the logic of this change, and it doesn't
> seem to regress anything after a bit of testing, so I've pushed it to
> Emacs 29.

Thanks Lars. As you may recall, I'm quite slow, often in more ways than
one. And that certainly applies here. Turns out I've been sitting on
slightly revised versions of both this and

  bug#50008: 28.0.50; ERC sends empty lines with user input

which you also recently added. For some reason (not sloth/dimwittedness,
I assure you), I only updated the versions of these patches living in
#48598 but neglected to follow suit with these two threads. So with much
contrition, I've isolated the differences and attached them here.

The updates to this bug attempt to preserve a couple API elements I
ditched/clobbered in what's already been installed (in the unlikely
event some poor sap or bot actually depended on them). This is mainly an
effort to embrace the spirit of being more responsible with and
accountable for my changes, something I've been slow to pick up on from
the great bandali. That said, I totally understand if you'd rather I
learn to live with my mistakes as well.

The minor changes to the other, "empty lines" patch just involve another
instance of superfluous newlines, this time generated from the function
`erc-cmd-default'. Thanks again and sorry for the disturbance.

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From 9a230327870370ca2d3861c6a891d83e3e8ed0d0 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Fri, 11 Jun 2021 03:55:07 -0700
Subject: [PATCH 1/2] Deprecate instead of redefine erc-server-reconnecting

* lisp/erc/erc-backend.el (erc-server-reconnecting,
erc--server-reconnecting): obsolete and replace the former with new
internal variant, which carries a simplified meaning.

(erc-server-reconnect-p, erc--server-reconnect-p): Obsolete and
replace the former with an internal function, and change behavior to
disregard `erc-server-reconnecting' when rendering verdict.

(erc-process-sentinel-2): ensure local var `erc--server-reconnecting'
is t when timers are scheduled or firing, and nil otherwise, including
after retries exhausted.  This agrees with the straightforward way
`erc-server-reconnecting' has always been used by `erc-cmd-RECONNECT'.

(erc-server-connect): set `erc--server-reconnecting'.

* lisp/erc/erc.el (erc-cmd-RECONNECT): use `erc--server-reconnecting'
instead of `erc-server-reconnecting'.
---
 lisp/erc/erc-backend.el | 26 +++++++++++++++++++++-----
 lisp/erc/erc.el         |  8 ++++++--
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/lisp/erc/erc-backend.el b/lisp/erc/erc-backend.el
index 6e5a768b70..69f63dfbc4 100644
--- a/lisp/erc/erc-backend.el
+++ b/lisp/erc/erc-backend.el
@@ -197,7 +197,13 @@ erc-server-quitting
   "Non-nil if the user requests a quit.")
 
 (defvar-local erc-server-reconnecting nil
-  "Non-nil if reconnecting or scheduled to.")
+  "Non-nil if the user requests an explicit reconnect, and the
+current IRC process is still alive.")
+(make-obsolete-variable 'erc-server-reconnecting
+                        "see `erc--server-reconnecting'" "29.1")
+
+(defvar-local erc--server-reconnecting nil
+  "Non-nil when reconnecting.")
 
 (defvar-local erc-server-timed-out nil
   "Non-nil if the IRC server failed to respond to a ping.")
@@ -532,7 +538,8 @@ erc-server-connect
     (with-current-buffer buffer
       (setq erc-server-process process)
       (setq erc-server-quitting nil)
-      (setq erc-server-reconnecting nil)
+      (setq erc-server-reconnecting nil
+            erc--server-reconnecting nil)
       (setq erc-server-timed-out nil)
       (setq erc-server-banned nil)
       (setq erc-server-error-occurred nil)
@@ -616,7 +623,7 @@ erc-server-filter-function
             (erc-parse-server-response process line)))))))
 
 (defun erc--server-reconnect-p (event)
-  "Return non-nil if ERC should attempt to reconnect automatically.
+  "Return non-nil when ERC should attempt to reconnect.
 EVENT is the message received from the closed connection process."
   (and erc-server-auto-reconnect
        (not erc-server-banned)
@@ -631,6 +638,14 @@ erc--server-reconnect-p
        ;; open-network-stream-nowait error for connection refused
        (if (string-match "^failed with code 111" event) 'nonblocking t)))
 
+(defun erc-server-reconnect-p (event)
+  "Return non-nil if ERC should attempt to reconnect automatically.
+EVENT is the message received from the closed connection process."
+  (declare (obsolete "see `erc--server-reconnect-p'" "29.1"))
+  (or (with-suppressed-warnings ((obsolete erc-server-reconnecting))
+        erc-server-reconnecting)
+      (erc--server-reconnect-p event)))
+
 (defun erc-process-sentinel-2 (event buffer)
   "Called when `erc-process-sentinel-1' has detected an unexpected disconnect."
   (if (not (buffer-live-p buffer))
@@ -642,7 +657,7 @@ erc-process-sentinel-2
         (if (not reconnect-p)
             ;; terminate, do not reconnect
             (progn
-              (setq erc-server-reconnecting nil)
+              (setq erc--server-reconnecting nil)
               (erc-display-message nil 'error (current-buffer)
                                    'terminated ?e event)
               ;; Update mode line indicators
@@ -651,7 +666,8 @@ erc-process-sentinel-2
           ;; reconnect
           (condition-case nil
               (progn
-                (setq erc-server-reconnecting t
+                (setq erc-server-reconnecting nil
+                      erc--server-reconnecting t
                       erc-server-reconnect-count (1+ erc-server-reconnect-count))
                 (setq delay erc-server-reconnect-timeout)
                 (run-at-time delay nil
diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 0da837012c..9fa1736535 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -3752,13 +3752,17 @@ erc-cmd-RECONNECT
       (setq buffer (current-buffer)))
     (with-current-buffer buffer
       (setq erc-server-quitting nil)
-      (setq erc-server-reconnecting t)
+      (with-suppressed-warnings ((obsolete erc-server-reconnecting))
+        (setq erc-server-reconnecting t))
+      (setq erc--server-reconnecting t)
       (setq erc-server-reconnect-count 0)
       (setq process (get-buffer-process (erc-server-buffer)))
       (if process
           (delete-process process)
         (erc-server-reconnect))
-      (setq erc-server-reconnecting nil)))
+      (with-suppressed-warnings ((obsolete erc-server-reconnecting))
+        (setq erc-server-reconnecting nil))
+      (setq erc--server-reconnecting nil)))
   t)
 (put 'erc-cmd-RECONNECT 'process-not-needed t)
 
-- 
2.31.1


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From a2d249d758f49ba528243204e32ecd0aa59c3105 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Sun, 13 Jun 2021 02:15:55 -0700
Subject: [PATCH 2/2] Don't send empty lines for unknown commands in ERC

* lisp/erc/erc.el (erc-cmd-default): prevent excess trailing newlines
from being sent.

* test/lisp/erc/erc-tests.el: Update `erc-process-input-line' test to
check for excess line feeds with unknown commands.
---
 lisp/erc/erc.el            |  2 +-
 test/lisp/erc/erc-tests.el | 15 ++++++++++++---
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 9fa1736535..8e2bb83360 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -2965,7 +2965,7 @@ erc-cmd-default
 this function.  LINE is sent to the server verbatim, and
 therefore has to contain the command itself as well."
   (erc-log (format "cmd: DEFAULT: %s" line))
-  (erc-server-send (substring line 1))
+  (erc-server-send (string-trim-right (substring line 1) "[\r\n]"))
   t)
 
 (defvar erc--read-time-period-history nil)
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 685f4e2bea..b2dbc1012d 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -236,6 +236,7 @@ erc-process-input-line
   (let (erc-server-last-sent-time
         erc-server-flood-queue
         (orig-erc-cmd-MSG (symbol-function 'erc-cmd-MSG))
+        (erc-default-recipients '("#chan"))
         calls)
     (with-temp-buffer
       (cl-letf (((symbol-function 'erc-cmd-MSG)
@@ -247,9 +248,7 @@ erc-process-input-line
                 ((symbol-function 'erc-server-process-alive)
                  (lambda () t))
                 ((symbol-function 'erc-server-send-queue)
-                 #'ignore)
-                ((symbol-function 'erc-default-target)
-                 (lambda () "" "#chan")))
+                 #'ignore))
 
         (ert-info ("Dispatch to user command handler")
 
@@ -259,6 +258,16 @@ erc-process-input-line
             (should (equal (pop erc-server-flood-queue)
                            '("PRIVMSG #chan :hi\r\n" . utf-8))))
 
+          (ert-info ("Quote preserves line intact")
+            (erc-process-input-line "/QUOTE FAKE foo bar\n")
+            (should (equal (pop erc-server-flood-queue)
+                           '("FAKE foo bar\r\n" . utf-8))))
+
+          (ert-info ("Unknown command respected")
+            (erc-process-input-line "/FAKE foo bar\n")
+            (should (equal (pop erc-server-flood-queue)
+                           '("FAKE foo bar\r\n" . utf-8))))
+
           (ert-info ("Spaces preserved")
             (erc-process-input-line "/msg #chan hi you\n")
             (should (equal (pop calls) " #chan hi you"))
-- 
2.31.1

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[Lars Ingebrigtsen]

"J.P." <jp@neverwas.me> writes:

> Thanks Lars. As you may recall, I'm quite slow, often in more ways than
> one. And that certainly applies here. Turns out I've been sitting on
> slightly revised versions of both this and
>
>   bug#50008: 28.0.50; ERC sends empty lines with user input

Thanks; I've now applied the updated patches, too.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#50007: 28.0.50; normalize logic surrounding erc-server-reconnecting

[J.P.]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Thanks; I've now applied the updated patches, too.

Oh, terrific! Much obliged, as always.