Re: bug#69597: 29.2; ERC 5.6-git: Add a new customizable variable controlling how Erc displays spoilers

From f5473bd8c8fba7c5685f1a4cadb6e6f3eb9c6f27 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email protected]>
Date: Thu, 7 Mar 2024 21:53:11 -0800
Subject: [PATCH 1/2] [5.6] Fix misleading test in erc-goodies

* test/lisp/erc/erc-goodies-tests.el
(erc-controls-highlight--inverse): Don't shadow hook with an
unrealistic subset of members, in this case a lone member:
`erc-controls-highlight'.  Adjust expected buffer state to reflect new
role of `erc-spoiler-face'.  (Bug#69597)
---
 test/lisp/erc/erc-goodies-tests.el | 60 +++++++++++++++---------------
 1 file changed, 29 insertions(+), 31 deletions(-)

diff --git a/test/lisp/erc/erc-goodies-tests.el b/test/lisp/erc/erc-goodies-tests.el
index 7013ce0c8fc..ddc29acff1e 100644
--- a/test/lisp/erc/erc-goodies-tests.el
+++ b/test/lisp/erc/erc-goodies-tests.el
@@ -131,37 +131,35 @@ erc-controls-highlight--examples
 
 (ert-deftest erc-controls-highlight--inverse ()
   (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)
-    (with-current-buffer (get-buffer-create "#chan")
-      (erc-mode)
-      (setq-local erc-interpret-mirc-color t)
-      (erc--initialize-markers (point) nil)
-
-      (let* ((m "Spoiler: \C-c0,0Hello\C-c1,1World!")
-             (msg (erc-format-privmessage "bob" m nil t)))
-        (erc-display-message nil nil (current-buffer) msg))
-      (forward-line -1)
-      (should (search-forward "<bob> " nil t))
-      (save-restriction
-        (narrow-to-region (point) (pos-eol))
-        (should (eq (get-text-property (+ 9 (point)) 'mouse-face)
-                    'erc-inverse-face))
-        (should (eq (get-text-property (1- (pos-eol)) 'mouse-face)
-                    'erc-inverse-face))
-        (erc-goodies-tests--assert-face
-         0 "Spoiler: " 'erc-default-face
-         '(fg:erc-color-face0 bg:erc-color-face0))
-        (erc-goodies-tests--assert-face
-         9 "Hello" '(erc-spoiler-face)
-         '( fg:erc-color-face0 bg:erc-color-face0
-            fg:erc-color-face1 bg:erc-color-face1))
-        (erc-goodies-tests--assert-face
-         18 " World" '(erc-spoiler-face)
-         '( fg:erc-color-face0 bg:erc-color-face0
-            fg:erc-color-face1 bg:erc-color-face1 )))
-      (when noninteractive
-        (kill-buffer)))))
+  (erc-tests-common-make-server-buf)
+  (with-current-buffer (erc--open-target "#chan")
+    (setq-local erc-interpret-mirc-color t)
+    (let* ((m "Spoiler: \C-c0,0Hello\C-c1,1World!")
+           (msg (erc-format-privmessage "bob" m nil t)))
+      (erc-display-message nil nil (current-buffer) msg))
+    (forward-line -1)
+    (should (search-forward "<bob> " nil t))
+    (save-restriction
+      ;; Narrow to EOL or start of right-side stamp.
+      (narrow-to-region (point) (line-end-position))
+      (should (eq (get-text-property (+ 9 (point)) 'mouse-face)
+                  'erc-spoiler-face))
+      (should (eq (get-text-property (1- (pos-eol)) 'mouse-face)
+                  'erc-spoiler-face))
+      ;; "Spoiler" appears in ERC default face.
+      (erc-goodies-tests--assert-face
+       0 "Spoiler: " 'erc-default-face
+       '(fg:erc-color-face0 bg:erc-color-face0))
+      ;; "Hello" is masked in all white.
+      (erc-goodies-tests--assert-face
+       9 "Hello" '(fg:erc-color-face0 bg:erc-color-face0)
+       '(fg:erc-color-face1 bg:erc-color-face1))
+      ;; "World" is masked in all black.
+      (erc-goodies-tests--assert-face
+       18 " World" '(fg:erc-color-face1 bg:erc-color-face1 )
+       '(fg:erc-color-face0 bg:erc-color-face0))))
+  (when noninteractive
+    (erc-tests-common-kill-buffers)))
 
 (defvar erc-goodies-tests--motd
   ;; This is from ergo's MOTD
-- 
2.44.0

From a66abc007c071f224b459cffdc2a451e36a80903 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <[email protected]>
Date: Thu, 7 Mar 2024 21:53:23 -0800
Subject: [PATCH 2/2] [5.6] Make important text props more resilient in ERC

* lisp/erc/erc-button.el (erc-button-remove-old-buttons): Restore
original `mouse-face' values in areas marked as important after
clobbering.
* lisp/erc/erc.el (erc--reserve-important-text-props): New function.
(erc--restore-important-text-props): New function.
* test/lisp/erc/erc-tests.el
(erc--restore-important-text-props): New test.
(Bug#69597)
---
 lisp/erc/erc-button.el     |  3 ++-
 lisp/erc/erc.el            | 32 +++++++++++++++++++++++
 test/lisp/erc/erc-tests.el | 52 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/lisp/erc/erc-button.el b/lisp/erc/erc-button.el
index 6b78e451b54..4b4930e5bff 100644
--- a/lisp/erc/erc-button.el
+++ b/lisp/erc/erc-button.el
@@ -528,7 +528,8 @@ erc-button-remove-old-buttons
    '(erc-callback nil
                   erc-data nil
                   mouse-face nil
-                  keymap nil)))
+                  keymap nil))
+  (erc--restore-important-text-props '(mouse-face)))
 
 (defun erc-button-add-button (from to fun nick-p &optional data regexp)
   "Create a button between FROM and TO with callback FUN and data DATA.
diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index cce3b2508fb..49b51c5d74c 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -3532,6 +3532,38 @@ erc--remove-from-prop-value-list
             old (get-text-property pos prop object)
             end (next-single-property-change pos prop object to)))))
 
+(defun erc--reserve-important-text-props (beg end plist)
+  "Record text-property pairs in PLIST as important between BEG and END.
+Also mark the message being inserted as containing these important props
+so modules performing destructive modifications can later restore them.
+Expect to run in a narrowed buffer at message-insertion time."
+  (when erc--msg-props
+    (let ((existing (erc--check-msg-prop 'erc--important-prop-names)))
+      (puthash 'erc--important-prop-names
+               (seq-union existing (cl-loop for (key _) on plist by #'cddr
+                                            collect key))
+               erc--msg-props)))
+  (erc--merge-prop beg end 'erc--important-props plist))
+
+;; FIXME use a region instead of point-min/max.
+(defun erc--restore-important-text-props (props)
+  "Restore PROPS where recorded in the accessible portion of the buffer.
+Expect to run in a narrowed buffer at message-insertion time."
+  (when-let ((registered (erc--check-msg-prop 'erc--important-prop-names))
+             (present (seq-intersection props registered))
+             (p (point-min))
+             (end (point-max)))
+    (while-let (((setq p (text-property-not-all p end
+                                                'erc--important-props nil)))
+                (val (get-text-property p 'erc--important-props))
+                (q (next-single-property-change p 'erc--important-props
+                                                nil end)))
+      (while-let ((k (pop val))
+                  (v (pop val)))
+        (when (memq k present)
+          (put-text-property p q k v)))
+      (setq p q))))
+
 (defvar erc-legacy-invisible-bounds-p nil
   "Whether to hide trailing rather than preceding newlines.
 Beginning in ERC 5.6, invisibility extends from a message's
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 085b063bdb2..6809d9db41d 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -2232,6 +2232,58 @@ erc--remove-from-prop-value-list/many
     (when noninteractive
       (kill-buffer))))
 
+(ert-deftest erc--restore-important-text-props ()
+  (erc-mode)
+  (let ((erc--msg-props (map-into '((erc--important-prop-names a))
+                                  'hash-table)))
+    (insert (propertize "foo" 'a 'A 'b 'B 'erc--important-props '(a A))
+            " "
+            (propertize "bar" 'c 'C 'a 'A 'b 'B
+                        'erc--important-props '(a A c C)))
+
+    ;; Attempt to restore a and c when only a is registered.
+    (remove-list-of-text-properties (point-min) (point-max) '(a c))
+    (erc--restore-important-text-props '(a c))
+    (should (erc-tests-common-equal-with-props
+             (buffer-string)
+             #("foo bar"
+               0 3 (a A b B erc--important-props (a A))
+               4 7 (a A b B erc--important-props (a A c C)))))
+
+    ;; Add d between 3 and 6.
+    (erc--reserve-important-text-props 3 6 '(d D))
+    (put-text-property 3 6 'd 'D)
+    (should (erc-tests-common-equal-with-props
+             (buffer-string)
+             #("foo bar" ; #1
+               0 2 (a A b B erc--important-props (a A))
+               2 3 (d D a A b B erc--important-props (d D a A))
+               3 4 (d D erc--important-props (d D))
+               4 5 (d D a A b B erc--important-props (d D a A c C))
+               5 7 (a A b B erc--important-props (a A c C)))))
+    ;; Remove a and d, and attempt to restore d.
+    (remove-list-of-text-properties (point-min) (point-max) '(a d))
+    (erc--restore-important-text-props '(d))
+    (should (erc-tests-common-equal-with-props
+             (buffer-string)
+             #("foo bar"
+               0 2 (b B erc--important-props (a A))
+               2 3 (d D b B erc--important-props (d D a A))
+               3 4 (d D erc--important-props (d D))
+               4 5 (d D b B erc--important-props (d D a A c C))
+               5 7 (b B erc--important-props (a A c C)))))
+
+    ;; Restore a only.
+    (erc--restore-important-text-props '(a))
+    (should (erc-tests-common-equal-with-props
+             (buffer-string)
+             #("foo bar" ; same as #1 above
+               0 2 (a A b B erc--important-props (a A))
+               2 3 (d D a A b B erc--important-props (d D a A))
+               3 4 (d D erc--important-props (d D))
+               4 5 (d D a A b B erc--important-props (d D a A c C))
+               5 7 (a A b B erc--important-props (a A c C)))))))
+
 (ert-deftest erc--split-string-shell-cmd ()
 
   ;; Leading and trailing space
-- 
2.44.0