Use smarter default for erc-server-reconnect-function

* doc/misc/erc.texi (Sample Configuration): Remove customization in
`use-package' declaration for `erc-server-reconnect-function' as well as
related language in the customization walk-through.  Do this because the
new default incorporates `erc-server-delayed-check-reconnect' behavior
for compatible connect functions.
* etc/ERC-NEWS: Announce new default for `erc-server-reconnect-function'.
* lisp/erc/erc-backend.el (erc-server-reconnect-function): Change
default to `erc-server-prefer-check-reconnect'.
(erc-server-delayed-check-reconnect): Use `process-send-string' instead
of `send-string'.
(erc--server-delayed-check-connectors): New variable.
(erc-server-prefer-check-reconnect): New function.
* test/lisp/erc/erc-scenarios-base-auto-recon.el
(erc-scenarios-base-auto-recon-unavailable)
(erc-scenarios-base-auto-recon-no-proto): Remove unnecessary
`erc-server-reconnect-function' binding because the new default
incorporates the behavior being tested for.
* test/lisp/erc/erc-scenarios-base-buffer-display.el
(erc-scenarios-base-buffer-display--reconnect-common):
* test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el
(erc-scenarios-common--base-compat-no-rename-bouncer):
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el
(erc-scenarios-base-netid-bouncer--recon-base):
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el
(erc-scenarios-base-netid-bouncer--recon-both):
* test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el
(erc-scenarios-base-netid-bouncer--reconnect-id-foo)
(erc-scenarios-base-netid-bouncer--reconnect-id-bar):
* test/lisp/erc/erc-scenarios-base-reconnect.el
(erc-scenarios-base-reconnect-timer)
(erc-scenarios-base-cancel-reconnect):
* test/lisp/erc/erc-scenarios-services-misc.el
(erc-scenarios-services-misc--reconnect-retry-nick):
* test/lisp/erc/erc-scenarios-stamp.el
(erc-scenarios-stamp--date-mode/reconnect): Explicitly bind
`erc-server-reconnect-function' to `erc-server-delayed-reconnect', the
former default, which does not do any probing.  (Bug#62044)

9 files changed, 20 insertions, 7 deletions

diff --git a/test/lisp/erc/erc-scenarios-base-auto-recon.el b/test/lisp/erc/erc-scenarios-base-auto-recon.el
index 808b1d8c4d4..d6a114147b3 100644
--- a/test/lisp/erc/erc-scenarios-base-auto-recon.el
+++ b/test/lisp/erc/erc-scenarios-base-auto-recon.el
@@ -24,6 +24,10 @@
   (let ((load-path (cons (ert-resource-directory) load-path)))
     (require 'erc-scenarios-common)))
 
+;; This tests `erc-server-delayed-check-reconnect', which is called by
+;; `erc-server-prefer-check-reconnect' (the default value of
+;; `erc-server-reconnect-function' as of ERC 5.6.1).
+
 (defun erc-scenarios-base-auto-recon--get-unused-port ()
   (let ((server (make-network-process :name "*erc-scenarios-base-auto-recon*"
                                       :host "localhost"
@@ -42,7 +46,6 @@
        (port (erc-scenarios-base-auto-recon--get-unused-port))
        (erc--server-reconnect-timeout-scale-function (lambda (_) 1))
        (erc-server-auto-reconnect t)
-       (erc-server-reconnect-function #'erc-server-delayed-check-reconnect)
        (expect (erc-d-t-make-expecter))
        (erc-scenarios-common-dialog "base/reconnect")
        (dumb-server nil))
@@ -89,7 +92,7 @@
         (erc-cmd-RECONNECT "cancel")
         (funcall expect 10 "canceled")))))
 
-;; In this test, a listener accepts but doesn't respond to any messages.
+;; Here, a listener accepts but doesn't respond to any messages.
 
 (ert-deftest erc-scenarios-base-auto-recon-no-proto ()
   :tags '(:expensive-test)
@@ -102,7 +105,6 @@
        (erc--server-reconnect-timeout-scale-function (lambda (_) 1))
        (erc--server-reconnect-timeout-check 0.5)
        (erc-server-auto-reconnect t)
-       (erc-server-reconnect-function #'erc-server-delayed-check-reconnect)
        (expect (erc-d-t-make-expecter)))
 
     (ert-info ("Session succeeds but cut short")
diff --git a/test/lisp/erc/erc-scenarios-base-buffer-display.el b/test/lisp/erc/erc-scenarios-base-buffer-display.el
index 5c3c526f86d..137db955db5 100644
--- a/test/lisp/erc/erc-scenarios-base-buffer-display.el
+++ b/test/lisp/erc/erc-scenarios-base-buffer-display.el
@@ -40,6 +40,7 @@
        (port (process-contact dumb-server :service))
        (expect (erc-d-t-make-expecter))
        (erc-server-flood-penalty 0.1)
+       (erc-server-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect t)
        erc-autojoin-channels-alist)
 
diff --git a/test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el b/test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el
index d1124269e0a..0bba0446ce6 100644
--- a/test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el
+++ b/test/lisp/erc/erc-scenarios-base-compat-rename-bouncer.el
@@ -43,6 +43,7 @@
        (chan-buf-foo (format "#chan@127.0.0.1:%d" port))
        (chan-buf-bar (format "#chan@127.0.0.1:%d<2>" port))
        (expect (erc-d-t-make-expecter))
+       (erc-server-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect auto)
        erc-server-buffer-foo erc-server-process-foo
        erc-server-buffer-bar erc-server-process-bar)
diff --git a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el
index e5453c40e56..04ccb86643b 100644
--- a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el
+++ b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-base.el
@@ -26,6 +26,7 @@
 
 (ert-deftest erc-scenarios-base-netid-bouncer--recon-base ()
   :tags '(:expensive-test)
-  (erc-scenarios-common--base-network-id-bouncer--reconnect nil nil))
+  (let ((erc-server-reconnect-function #'erc-server-delayed-reconnect))
+    (erc-scenarios-common--base-network-id-bouncer--reconnect nil nil)))
 
 ;;; erc-scenarios-base-netid-bouncer-recon-base.el ends here
diff --git a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el
index 09ddcef5fa3..f0939d6204a 100644
--- a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el
+++ b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-both.el
@@ -27,6 +27,8 @@
 
 (ert-deftest erc-scenarios-base-netid-bouncer--recon-both ()
   :tags '(:expensive-test)
-  (erc-scenarios-common--base-network-id-bouncer--reconnect 'foo-id 'bar-id))
+  (let ((erc-server-reconnect-function #'erc-server-delayed-reconnect))
+    (erc-scenarios-common--base-network-id-bouncer--reconnect 'foo-id
+                                                              'bar-id)))
 
 ;;; erc-scenarios-base-netid-bouncer-recon-both.el ends here
diff --git a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el
index 253ab4f72c9..d77a4287976 100644
--- a/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el
+++ b/test/lisp/erc/erc-scenarios-base-netid-bouncer-recon-id.el
@@ -26,11 +26,13 @@
 
 (ert-deftest erc-scenarios-base-netid-bouncer--reconnect-id-foo ()
   :tags '(:expensive-test)
-  (erc-scenarios-common--base-network-id-bouncer--reconnect 'foo-id nil))
+  (let ((erc-server-reconnect-function #'erc-server-delayed-reconnect))
+    (erc-scenarios-common--base-network-id-bouncer--reconnect 'foo-id nil)))
 
 (ert-deftest erc-scenarios-base-netid-bouncer--reconnect-id-bar ()
   :tags '(:expensive-test)
-  (erc-scenarios-common--base-network-id-bouncer--reconnect nil 'bar-id))
+  (let ((erc-server-reconnect-function #'erc-server-delayed-reconnect))
+    (erc-scenarios-common--base-network-id-bouncer--reconnect nil 'bar-id)))
 
 
 ;;; erc-scenarios-base-netid-bouncer-recon-id.el ends here
diff --git a/test/lisp/erc/erc-scenarios-base-reconnect.el b/test/lisp/erc/erc-scenarios-base-reconnect.el
index 6f968b9fcbc..2dc34362fbf 100644
--- a/test/lisp/erc/erc-scenarios-base-reconnect.el
+++ b/test/lisp/erc/erc-scenarios-base-reconnect.el
@@ -37,6 +37,7 @@
        (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-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect t)
        erc-autojoin-channels-alist
        erc-server-buffer)
@@ -144,6 +145,7 @@
        (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-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect t)
        erc-autojoin-channels-alist
        erc-server-buffer)
diff --git a/test/lisp/erc/erc-scenarios-services-misc.el b/test/lisp/erc/erc-scenarios-services-misc.el
index 47d0bcff41a..ee35e8b93db 100644
--- a/test/lisp/erc/erc-scenarios-services-misc.el
+++ b/test/lisp/erc/erc-scenarios-services-misc.el
@@ -155,6 +155,7 @@
        (dumb-server (erc-d-run "localhost" t 'reconnect-retry
                                'reconnect-retry-again))
        (port (process-contact dumb-server :service))
+       (erc-server-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect t)
        (erc-modules `(services-regain sasl ,@erc-modules))
        (erc-services-regain-alist
diff --git a/test/lisp/erc/erc-scenarios-stamp.el b/test/lisp/erc/erc-scenarios-stamp.el
index 8aea091333b..86074a9c35a 100644
--- a/test/lisp/erc/erc-scenarios-stamp.el
+++ b/test/lisp/erc/erc-scenarios-stamp.el
@@ -188,6 +188,7 @@
       ((erc-scenarios-common-dialog "base/reconnect")
        (erc-server-flood-penalty 0.1)
        (erc-stamp--tz t)
+       (erc-server-reconnect-function #'erc-server-delayed-reconnect)
        (erc-server-auto-reconnect t)
        ;; Start close to midnight: 2024-06-02T23:58:11.055Z
        (erc-stamp--current-time (if (< emacs-major-version 29)