Add helper for restoring local session vars in ERC

* lisp/erc/erc-common.el (erc--input-split): Suppress warning for
obsolete variable `erc-send-this' in init form.
* lisp/erc/erc-goodies.el (erc--keep-place-indicator-setup): Use macro
`erc--restore-initialize-priors' to preserve last session's indicator
position, if any.
(erc-keep-place-indicator-mode, erc-keep-place-indicator-enable): Use
convenience function to show missing-dependency notice.
* lisp/erc/erc-sasl.el (erc-sasl-auth-source-password-as-host): Merge
redundant `when' forms for clarity.
(erc-sasl--init): Remove unused function.
(erc-sasl-mode, erc-sasl-enable): Use helper to restore
`erc-sasl--options', essentially inlining the body of the now defunct
`erc-sasl--init'.
* lisp/erc/erc.el (erc--restore-initialize-priors): New macro to help
local modules and mode hooks prefer existing state over initializing
anew.
(erc--warn-once-before-connect): Add helper function to display
an "error notice" just after module setup.
(erc-accidental-paste-threshold-seconds) Improve doc string.
* test/lisp/erc/erc-goodies-tests.el
(erc-controls-highlight--examples, erc-controls-highlight--inverse,
erc-controls-highlight--motd, erc-keep-place-indicator-mode): Remove
feature check.  For the latter, also start fake process and shadow
`erc-connect-pre-hook'.
* test/lisp/erc/erc-tests.el (erc--restore-initialize-priors): New
test.  Also see test/lisp/erc/erc-scenarios-base-local-modules.el for
a more realistic exercising of this functionality.  (Bug#60936)

2 files changed, 19 insertions, 13 deletions

diff --git a/test/lisp/erc/erc-goodies-tests.el b/test/lisp/erc/erc-goodies-tests.el
index a1f53c5bf88..7acacb319f1 100644
--- a/test/lisp/erc/erc-goodies-tests.el
+++ b/test/lisp/erc/erc-goodies-tests.el
@@ -21,7 +21,6 @@
 ;;; Code:
 (require 'ert-x)
 (require 'erc-goodies)
-(declare-function erc--initialize-markers "erc" (old-point continued) t)
 
 (defun erc-goodies-tests--assert-face (beg end-str present &optional absent)
   (setq beg (+ beg (point-min)))
@@ -44,9 +43,6 @@
 ;; https://modern.ircdocs.horse/formatting.html
 
 (ert-deftest erc-controls-highlight--examples ()
-  ;; FIXME remove after adding
-  (unless (fboundp 'erc--initialize-markers)
-    (ert-skip "Missing required function"))
   (should (eq t erc-interpret-controls-p))
   (let ((erc-insert-modify-hook '(erc-controls-highlight))
         erc-kill-channel-hook erc-kill-server-hook erc-kill-buffer-hook)
@@ -130,9 +126,6 @@
 ;; in a high-contrast face.
 
 (ert-deftest erc-controls-highlight--inverse ()
-  ;; FIXME remove after adding
-  (unless (fboundp 'erc--initialize-markers)
-    (ert-skip "Missing required function"))
   (should (eq t erc-interpret-controls-p))
   (let ((erc-insert-modify-hook '(erc-controls-highlight))
         erc-kill-channel-hook erc-kill-server-hook erc-kill-buffer-hook)
@@ -212,9 +205,6 @@
     (":- ")))
 
 (ert-deftest erc-controls-highlight--motd ()
-  ;; FIXME remove after adding
-  (unless (fboundp 'erc--initialize-markers)
-    (ert-skip "Missing required function"))
   (should (eq t erc-interpret-controls-p))
   (let ((erc-insert-modify-hook '(erc-controls-highlight))
         erc-kill-channel-hook erc-kill-server-hook erc-kill-buffer-hook)
@@ -256,12 +246,12 @@
 ;; needed.
 
 (ert-deftest erc-keep-place-indicator-mode ()
-  ;; FIXME remove after adding
-  (unless (fboundp 'erc--initialize-markers)
-    (ert-skip "Missing required function"))
   (with-current-buffer (get-buffer-create "*erc-keep-place-indicator-mode*")
     (erc-mode)
     (erc--initialize-markers (point) nil)
+    (setq erc-server-process
+          (start-process "sleep" (current-buffer) "sleep" "1"))
+    (set-process-query-on-exit-flag erc-server-process nil)
     (let ((assert-off
            (lambda ()
              (should-not erc-keep-place-indicator-mode)
@@ -275,6 +265,7 @@
              (should erc-keep-place-mode)))
           ;;
           erc-insert-pre-hook
+          erc-connect-pre-hook
           erc-modules)
 
       (funcall assert-off)
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index be5a566a268..b624186d88d 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -868,6 +868,21 @@
       (should-not (erc--valid-local-channel-p "#chan"))
       (should (erc--valid-local-channel-p "&local")))))
 
+(ert-deftest erc--restore-initialize-priors ()
+  ;; This `pcase' expands to 100+k.  Guess we could do something like
+  ;; (and `(,_ ((,e . ,_) . ,_) . ,_) v) first and then return a
+  ;; (equal `(if-let* ((,e ...)...)...) v) to cut it down to < 1k.
+  (should (pcase (macroexpand-1 '(erc--restore-initialize-priors erc-my-mode
+                                   foo (ignore 1 2 3)
+                                   bar #'spam))
+            (`(if-let* ((,e (or erc--server-reconnecting erc--target-priors))
+                        ((alist-get 'erc-my-mode ,e)))
+                  (setq foo (alist-get 'foo ,e)
+                        bar (alist-get 'bar ,e))
+                (setq foo (ignore 1 2 3)
+                      bar #'spam))
+             t))))
+
 (ert-deftest erc--target-from-string ()
   (should (equal (erc--target-from-string "#chan")
                  #s(erc--target-channel "#chan" \#chan)))