Preserve prompt in erc-cmd-CLEAR

* etc/ERC-NEWS: Mention behavioral changes to functionality provided
by the `truncate' and `log' modules and also the "/CLEAR" command.
* lisp/erc/erc-log.el (erc-truncate-buffer-on-save): Deprecate option
because three's a crowd, and ERC already has a dedicated module as
well as a slash command for this purpose.  And although this commit
restores functionality, this option has been unusable since at least
the release of ERC 5.5, with no known complaints received thus far.
Also, the doc string of `erc-save-buffer-in-logs' makes no mention of
this feature WRT interactive invocations or otherwise.
(erc-log-mode, erc-log-enable, erc-log-disable): Subscribe to
new internal hook `erc--pre-clear-functions'.
(erc-log--save-in-progress-p): New variable to help restore
`erc-truncate-buffer-on-save' and promote code reuse.
(erc-logging-enabled): Guard with `erc-log--saved-in-progress-p'.
(erc-save-buffer-in-logs): Overload `buffer' parameter to allow
various hooks to supply a non-buffer as well.  Warn when people use
`erc-truncate-buffer-on-save', which is now deprecated.
* lisp/erc/erc-stamp.el (erc-stamp-mode, erc-stamp-enable,
erc-stamp-disable): Subscribe to `erc--pre-clear-functions'.
(erc-stamp--update-saved-position): New function for updating
last-logged marker on `erc-stamp--insert-date-function'.
(erc-stamp--reset-on-clear): New function to forget last inserted
stamps when truncating.
* lisp/erc/erc-truncate.el (erc-truncate-mode, erc-truncate-enable,
erc-truncate-disable): Use `erc-insert-done-hook' instead of
`erc-insert-post-hook', as implicitly suggested by an ancient comment,
which ponders whether truncating the buffer at the insertion phase may
be harmful to other hook members.
(erc-truncate-buffer-to-size): Set truncation boundary at message
break instead of line break.  Run `erc--pre-clear-functions'.
(erc-truncate-buffer): Save excursion.  This should probably be
handled by `erc-truncate-buffer-to-size' instead, but that's
likelier to cause breakage in third-party code.
* lisp/erc/erc.el (erc--pre-clear-functions): New internal hook.
(erc-cmd-CLEAR): Run `erc--pre-clear-functions' before clearing, and
don't blow away prompt.  The latter was a regression caused by
05f6fdb9e78 "Preserve ERC prompt and its bounding markers".
* test/lisp/erc/erc-scenarios-log.el: New file.  (Bug#60936)

1 files changed, 207 insertions, 0 deletions

diff --git a/test/lisp/erc/erc-scenarios-log.el b/test/lisp/erc/erc-scenarios-log.el
new file mode 100644
index 00000000000..c37e6b323aa
--- /dev/null
+++ b/test/lisp/erc/erc-scenarios-log.el
@@ -0,0 +1,207 @@
+;;; erc-scenarios-log.el --- erc-log scenarios -*- lexical-binding: t -*-
+
+;; Copyright (C) 2023 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert-x)
+(eval-and-compile
+  (let ((load-path (cons (ert-resource-directory) load-path)))
+    (require 'erc-scenarios-common)))
+
+(require 'erc-log)
+(require 'erc-truncate)
+
+(defvar erc-timestamp-format-left)
+
+(ert-deftest erc-scenarios-log--kill-hook ()
+  :tags '(:expensive-test)
+  (erc-scenarios-common-with-cleanup
+      ((erc-scenarios-common-dialog "base/assoc/bouncer-history")
+       (dumb-server (erc-d-run "localhost" t 'foonet))
+       (tempdir (make-temp-file "erc-tests-log." t nil nil))
+       (erc-log-channels-directory tempdir)
+       (erc-modules (cons 'log erc-modules))
+       (port (process-contact dumb-server :service))
+       (logfile (expand-file-name (format "#chan!tester@127.0.0.1:%d.txt" port)
+                                  tempdir))
+       (erc-server-flood-penalty 0.1)
+       (expect (erc-d-t-make-expecter)))
+
+    (ert-info ("Connect to foonet")
+      (with-current-buffer (erc :server "127.0.0.1"
+                                :port port
+                                :nick "tester"
+                                :password "foonet:changeme"
+                                :full-name "tester")
+        (should (string= (buffer-name) (format "127.0.0.1:%d" port)))
+        (funcall expect 5 "foonet")))
+
+    (with-current-buffer (erc-d-t-wait-for 5 (get-buffer "#chan"))
+      (funcall expect 10 "was created on")
+      (funcall expect 10 "please your lordship")
+      (with-current-buffer "foonet"
+        (delete-process erc-server-process)
+        (funcall expect 5 "failed"))
+      (should-not (file-exists-p logfile))
+      (kill-buffer)
+      (should (file-exists-p logfile)))
+
+    (with-temp-buffer
+      (insert-file-contents logfile)
+      (funcall expect 1 "You have joined")
+      (funcall expect 1 "Playback Complete.")
+      (funcall expect 1 "please your lordship"))
+
+    (erc-log-mode -1)
+    (if noninteractive
+        (delete-directory tempdir :recursive)
+      (add-hook 'kill-emacs-hook
+                (lambda () (delete-directory tempdir :recursive))))))
+
+;; This shows that, in addition to truncating the buffer, /clear also
+;; syncs the log.
+
+(ert-deftest erc-scenarios-log--clear-stamp ()
+  :tags '(:expensive-test)
+  (erc-scenarios-common-with-cleanup
+      ((erc-scenarios-common-dialog "base/assoc/bouncer-history")
+       (dumb-server (erc-d-run "localhost" t 'foonet))
+       (tempdir (make-temp-file "erc-tests-log." t nil nil))
+       (erc-log-channels-directory tempdir)
+       (erc-modules (cons 'log erc-modules))
+       (erc-timestamp-format-left "\n[%a %b %e %Y @@STAMP@@]\n")
+       (port (process-contact dumb-server :service))
+       (logfile (expand-file-name (format "#chan!tester@127.0.0.1:%d.txt" port)
+                                  tempdir))
+       (erc-server-flood-penalty 0.1)
+       (expect (erc-d-t-make-expecter)))
+
+    (unless noninteractive
+      (add-hook 'kill-emacs-hook
+                (lambda () (delete-directory tempdir :recursive))))
+
+    (ert-info ("Connect to foonet")
+      (with-current-buffer (erc :server "127.0.0.1"
+                                :port port
+                                :nick "tester"
+                                :password "foonet:changeme"
+                                :full-name "tester")
+        (should (string= (buffer-name) (format "127.0.0.1:%d" port)))
+        (funcall expect 5 "foonet")))
+
+    (with-current-buffer (erc-d-t-wait-for 5 (get-buffer "#chan"))
+      (funcall expect 10 "@@STAMP@@")
+      (funcall expect 10 "Grows, lives")
+      (should-not (file-exists-p logfile))
+      (goto-char (point-max))
+      (erc-cmd-CLEAR)
+      (should (file-exists-p logfile))
+      (funcall expect 10 "please your lordship")
+      (ert-info ("Buffer truncated")
+        (goto-char (point-min))
+        (funcall expect 10 "@@STAMP@@" (point)) ; reset
+        (funcall expect -0.1 "Grows, lives")
+        (funcall expect 1 "For these two")))
+
+    (ert-info ("Current contents saved")
+      (with-temp-buffer
+        (insert-file-contents logfile)
+        (funcall expect 1 "@@STAMP@@")
+        (funcall expect 1 "You have joined")
+        (funcall expect 1 "Playback Complete.")
+        (funcall expect 1 "Grows, lives")
+        (funcall expect -0.01 "please your lordship")))
+
+    (ert-info ("Remainder saved, timestamp printed when option non-nil")
+      (with-current-buffer "foonet"
+        (delete-process erc-server-process)
+        (funcall expect 5 "failed"))
+      (kill-buffer "#chan")
+      (with-temp-buffer
+        (insert-file-contents logfile)
+        (funcall expect 1 "@@STAMP@@")
+        (funcall expect 1 "Grows, lives")
+        (funcall expect -0.01 "@@STAMP@@")
+        (forward-line 1) ; no blank, no timestamp
+        (should (looking-at (rx "<bob> alice: For these two hours,")))
+        (funcall expect 1 "please your lordship")))
+
+    (erc-log-mode -1)
+    (when noninteractive (delete-directory tempdir :recursive))))
+
+(ert-deftest erc-scenarios-log--truncate ()
+  :tags '(:expensive-test)
+  (erc-scenarios-common-with-cleanup
+      ((erc-scenarios-common-dialog "base/assoc/bouncer-history")
+       (dumb-server (erc-d-run "localhost" t 'foonet))
+       (tempdir (make-temp-file "erc-tests-log." t nil nil))
+       (erc-log-channels-directory tempdir)
+       (erc-modules (cons 'truncate (cons 'log erc-modules)))
+       (erc-max-buffer-size 512)
+       (port (process-contact dumb-server :service))
+       (logchan (expand-file-name (format "#chan!tester@127.0.0.1:%d.txt" port)
+                                  tempdir))
+       (logserv (expand-file-name
+                 (format "127.0.0.1:%d!tester@127.0.0.1:%d.txt" port port)
+                 tempdir))
+       (erc-server-flood-penalty 0.1)
+       (expect (erc-d-t-make-expecter)))
+
+    (unless noninteractive
+      (add-hook 'kill-emacs-hook
+                (lambda () (delete-directory tempdir :recursive))))
+
+    (ert-info ("Connect to foonet")
+      (with-current-buffer (erc :server "127.0.0.1"
+                                :port port
+                                :nick "tester"
+                                :password "foonet:changeme"
+                                :full-name "tester")
+        (should (string= (buffer-name) (format "127.0.0.1:%d" port)))
+        (should-not (file-exists-p logserv))
+        (should-not (file-exists-p logchan))
+        (funcall expect 10 "*** MAXLIST=beI:60")
+        (should (= (pos-bol) (point-min)))
+        (should (file-exists-p logserv))))
+
+    (ert-info ("Log file ahead of truncation point")
+      ;; Log contains lines still present in buffer.
+      (with-temp-buffer
+        (insert-file-contents logserv)
+        (funcall expect 10 "*** MAXLIST=beI:60")))
+
+    (with-current-buffer (erc-d-t-wait-for 5 (get-buffer "#chan"))
+      (funcall expect 10 "please your lordship")
+      (should (file-exists-p logchan))
+      (funcall expect -0.1 "[07:04:37] alice: Here," (point-min)))
+
+    (ert-info ("Log ahead of truncation point")
+      (with-temp-buffer
+        (insert-file-contents logchan)
+        (funcall expect 1 "You have joined")
+        (funcall expect 1 "[07:04:37] alice: Here,")
+        (funcall expect 1 "loathed enemy")
+        (funcall expect -0.1 "please your lordship")))
+
+    (erc-log-mode -1)
+    (when noninteractive (delete-directory tempdir :recursive))))
+
+;;; erc-scenarios-log.el ends here