Subject: bug#51753: ERC switches to channel buffer on reconnect

From: "J.P." <[email-masked]>
Date: Sun, 21 Nov 2021 14:54:14 -0800

Stefan Kangas <[email-masked]> writes:

> "J.P." <[email-masked]> writes:
>
>> It just occurred to me that we may also want to reset
>> `erc--server-last-reconnect-count' at some point after all (re)JOINing
>> is done with (both client- and server-initiated) so that the option
>> `erc-join-buffer' regains precedence over `erc-reconnect-display' for
>> the remainder of the connection. Doing so in `erc-cmd-JOIN' would cover
>> manually issued /JOINs as well as invocations of `erc-join-channel'.
>
> Sounds good to me.

Great. Added. Thanks.

Updated tests: https://gitlab.com/jpneverwas/erc-v3/-/blob/454ef4674af3d784bb47a81db5e7d526fb30a705/test/erc-scenarios.el#L1642

>From a9c084d4dbfad1e34e23f1d2451a34beadfdc258 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Sun, 21 Nov 2021 00:40:31 -0800
Subject: NOT A PATCH

F. Jason Park (1):
  Customize displaying of ERC buffers on reconnect

 lisp/erc/erc-backend.el |  3 +++
 lisp/erc/erc.el         | 24 ++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

Interdiff:
diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 01be8ed397..181da76f8e 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -3243,6 +3243,7 @@ erc-cmd-JOIN
             (switch-to-buffer (if (get-buffer chnl-name)
                                   chnl-name
                                 (concat chnl-name "/" server)))
+          (setq erc--server-last-reconnect-count 0)
 	  (erc-server-join-channel server chnl key)))))
   t)
 
-- 
2.31.1

>From a9c084d4dbfad1e34e23f1d2451a34beadfdc258 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email-masked]>
Date: Thu, 18 Nov 2021 23:39:54 -0800
Subject: [PATCH 1/1] Customize displaying of ERC buffers on reconnect

* lisp/erc/erc-backend.el (erc--server-last-reconnect-count):
Add variable to record last reconnect tally.

* lisp/erc/erc.el (erc-reconnect-buffer): Add option to specify
channel-buffer display behavior on reconnect.
(erc-setup-buffer): Use option `erc-reconnect-buffer' if warranted.
(erc-connection-established): Record reconnect count in internal var
before resetting.
(erc-cmd-JOIN): Forget last reconnect count when issuing a manual
/JOIN command.
---
 lisp/erc/erc-backend.el |  3 +++
 lisp/erc/erc.el         | 24 ++++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/lisp/erc/erc-backend.el b/lisp/erc/erc-backend.el
index 69f63dfbc4..0d586268e9 100644
--- a/lisp/erc/erc-backend.el
+++ b/lisp/erc/erc-backend.el
@@ -193,6 +193,9 @@ erc-server-connected
 (defvar-local erc-server-reconnect-count 0
   "Number of times we have failed to reconnect to the current server.")
 
+(defvar-local erc--server-last-reconnect-count 0
+  "Snapshot of reconnect count when the connection was established.")
+
 (defvar-local erc-server-quitting nil
   "Non-nil if the user requests a quit.")
 
diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index c5a4fbe5a0..181da76f8e 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -1521,6 +1521,21 @@ erc-join-buffer
                  (const :tag "Use current buffer" buffer)
                  (const :tag "Use current buffer" t)))
 
+(defcustom erc-reconnect-display nil
+  "How (and whether) to display a channel buffer upon reconnecting.
+
+This only affects automatic reconnections and is ignored when issuing a
+/reconnect command or reinvoking `erc-tls' with the same args (assuming
+success, of course).  See `erc-join-buffer' for a description of
+possible values."
+  :group 'erc-buffers
+  :type '(choice (const :tag "Use value of `erc-join-buffer'" nil)
+                 (const :tag "Split window and select" window)
+                 (const :tag "Split window, don't select" window-noselect)
+                 (const :tag "New frame" frame)
+                 (const :tag "Bury in new buffer" bury)
+                 (const :tag "Use current buffer" buffer)))
+
 (defcustom erc-frame-alist nil
   "Alist of frame parameters for creating erc frames.
 A value of nil means to use `default-frame-alist'."
@@ -1950,7 +1965,10 @@ erc-update-modules
 
 (defun erc-setup-buffer (buffer)
   "Consults `erc-join-buffer' to find out how to display `BUFFER'."
-  (pcase erc-join-buffer
+  (pcase (if (zerop (erc-with-server-buffer
+                      erc--server-last-reconnect-count))
+             erc-join-buffer
+           (or erc-reconnect-display erc-join-buffer))
     ('window
      (if (active-minibuffer-window)
          (display-buffer buffer)
@@ -3225,6 +3243,7 @@ erc-cmd-JOIN
             (switch-to-buffer (if (get-buffer chnl-name)
                                   chnl-name
                                 (concat chnl-name "/" server)))
+          (setq erc--server-last-reconnect-count 0)
 	  (erc-server-join-channel server chnl key)))))
   t)
 
@@ -4722,7 +4741,8 @@ erc-connection-established
             (nick (car (erc-response.command-args parsed)))
             (buffer (process-buffer proc)))
         (setq erc-server-connected t)
-	(setq erc-server-reconnect-count 0)
+        (setq erc--server-last-reconnect-count erc-server-reconnect-count
+              erc-server-reconnect-count 0)
         (erc-update-mode-line)
         (erc-set-initial-user-mode nick buffer)
         (erc-server-setup-periodical-ping buffer)
-- 
2.31.1