Improve auto-reconnect visibility in ERC

* lisp/erc/erc-backend.el (erc--server-reconnect-timer): New variable.
(erc-server-reconnect-function): New user option.
(erc-process-sentinel-2): Display time remaining until next
reconnection attempt.  Also remove condition case and move bulk of
else condition logic to `erc-schedule-reconnect'.  More importantly,
no longer set `erc--server-reconnecting here').
(erc-server-connect): Initialize `erc--server-reconnect-timer' to nil.
(erc-server-reconnect): Set `erc-server--reconnecting' here.
(erc--mode-line-process-reconnecting): New constant to store value for
"reconnect" state of `mode-line-process'.
(erc--cancel-auto-reconnect-timer): New function to cancel
auto-reconnect timer and print message.
(erc-schedule-reconnect): New function for scheduling another
reconnect attempt.

* lisp/erc/erc.el (erc-open): Only update mode line for target
buffers. For server buffers, let `erc-login' and/or process sentinels
take care of it.
(erc--cmd-reconnect, erc-cmd-RECONNECT): Rename latter to former, a
new function, but repurpose existing to recognize newly allowed
additional arguments and act accordingly.  In new internal function,
cancel an existing auto-reconnect timer, if any, before proceeding.
Defer to `erc-server-reconnect' to set `erc--server-reconnecting'.
Fix `with-suppressed-warnings' form.
(erc-update-mode-line-buffer): Show "reconnecting in Ns" for
`mode-line-process' when awaiting an automatic reconnect attempt.
(erc-message-english-reconnecting,
erc-message-english-reconnect-canceled): Add new message functions to
English catalog.

* lisp/erc/erc-pcomplete.el (pcomplete/erc-mode/RECONNECT): Perform
completion for newly subcommand-aware `erc-cmd-RECONNECT'.

* lisp/erc/erc-scenarios-base-reconnect
(erc-scenarios-base-cancel-reconnect): Add new test case for canceling
reconnect timers.  (Bug#58840.)

1 files changed, 46 insertions, 0 deletions

diff --git a/test/lisp/erc/erc-scenarios-base-reconnect.el b/test/lisp/erc/erc-scenarios-base-reconnect.el
index 49298dc5942..8762f33b303 100644
--- a/test/lisp/erc/erc-scenarios-base-reconnect.el
+++ b/test/lisp/erc/erc-scenarios-base-reconnect.el
@@ -224,4 +224,50 @@
       (with-current-buffer "#chan"
         (funcall expect 10 "here comes the lady")))))
 
+
+(ert-deftest erc-scenarios-base-cancel-reconnect ()
+  :tags '(:expensive-test)
+  (erc-scenarios-common-with-cleanup
+      ((erc-scenarios-common-dialog "base/reconnect")
+       (dumb-server (erc-d-run "localhost" t 'timer 'timer 'timer-last))
+       (port (process-contact dumb-server :service))
+       (expect (erc-d-t-make-expecter))
+       (erc-server-auto-reconnect t)
+       erc-autojoin-channels-alist
+       erc-server-buffer)
+
+    (ert-info ("Connect to foonet")
+      (setq erc-server-buffer (erc :server "127.0.0.1"
+                                   :port port
+                                   :nick "tester"
+                                   :password "changeme"
+                                   :full-name "tester"))
+      (with-current-buffer erc-server-buffer
+        (should (string= (buffer-name) (format "127.0.0.1:%d" port)))))
+
+    (ert-info ("Two connection attempts, all stymied")
+      (with-current-buffer erc-server-buffer
+        (ert-info ("First two attempts behave normally")
+          (dotimes (n 2)
+            (ert-info ((format "Initial attempt %d" (1+ n)))
+              (funcall expect 3 "Opening connection")
+              (funcall expect 2 "Password incorrect")
+              (funcall expect 2 "Connection failed!")
+              (funcall expect 2 "Re-establishing connection"))))
+        (ert-info ("/RECONNECT cancels timer but still attempts to connect")
+          (erc-cmd-RECONNECT)
+          (funcall expect 2 "Canceled")
+          (funcall expect 3 "Opening connection")
+          (funcall expect 2 "Password incorrect")
+          (funcall expect 2 "Connection failed!")
+          (funcall expect 2 "Re-establishing connection"))
+        (ert-info ("Explicitly cancel timer")
+          (erc-cmd-RECONNECT "cancel")
+          (funcall expect 2 "Canceled")
+          (erc-d-t-absent-for 1 "Opening connection" (point)))))
+
+    (ert-info ("Server buffer is unique and temp name is absent")
+      (should (equal (list (get-buffer (format "127.0.0.1:%d" port)))
+                     (erc-scenarios-common-buflist "127.0.0.1"))))))
+
 ;;; erc-scenarios-base-reconnect.el ends here