[nongnu] elpa/undo-fu-session d90d42ddba 2/2: Workaround bug in Emacs 30 where session data wasn't loading

[ELPA Syncer]

branch: elpa/undo-fu-session
commit d90d42ddba8fa42ef5dc109196545caeabb42b75
Author: Campbell Barton <ideasman42@gmail.com>
Commit: Campbell Barton <ideasman42@gmail.com>

    Workaround bug in Emacs 30 where session data wasn't loading
    
    There seems to be an order of initialization bug when the variable
    auto-compresson-mode can be set without the mode being enabled.
    (when loading files from the command line).
    
    Workaround the bug by calling jka-compr-installed-p instead
    of using the mode variable.
---
 undo-fu-session.el | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/undo-fu-session.el b/undo-fu-session.el
index 9fb29fb1b4..3bfc5a4e5f 100755
--- a/undo-fu-session.el
+++ b/undo-fu-session.el
@@ -113,6 +113,32 @@ Enforcing removes the oldest files."
   :type 'integer)
 
 
+;; ---------------------------------------------------------------------------
+;; Compatibility
+;;
+
+;; Workaround bug in Emacs 30, where this macro fails when to enable
+;; auto-compression-mode when a file is loaded from the command line.
+;; The problem seems to be `auto-compression-mode' is true,
+;; but the mode has not started when undo-fu-session runs.
+;; Workaround the bug by replacing the auto-compression-mode
+;; check with `jka-compr-installed-p'.
+;; I didn't manage to redo this in simple test cases (for a report),
+;; so use a workaround for now.
+(defmacro undo-fu-session--with-auto-compression-mode (&rest body)
+  "Evaluate BODY with automatic file compression and uncompression enabled."
+  (declare (indent 0))
+  (let ((already-installed (make-symbol "already-installed")))
+    `(let ((,already-installed (jka-compr-installed-p)))
+       (unwind-protect
+           (progn
+             (unless ,already-installed
+               (auto-compression-mode 1))
+             ,@body)
+         (unless ,already-installed
+           (auto-compression-mode -1))))))
+
+
 ;; ---------------------------------------------------------------------------
 ;; Utility Functions
 ;;
@@ -448,7 +474,7 @@ Argument PENDING-LIST an `pending-undo-list' compatible 
list."
             (push file-src-full files-to-convert)))))
 
     (message "Operating on %d file(s) in \"%s\"" count-pending 
undo-fu-session-directory)
-    (with-auto-compression-mode
+    (undo-fu-session--with-auto-compression-mode
       (dolist (file-src-full files-to-convert)
         (let ((file-dst-full (file-name-with-extension file-src-full ext-dst)))
           (message "File %d of %d: %s"
@@ -678,7 +704,7 @@ Argument PENDING-LIST an `pending-undo-list' compatible 
list."
         (unless (file-exists-p undo-file)
           (undo-fu-session--file-limit-enforce)))
 
-      (with-auto-compression-mode
+      (undo-fu-session--with-auto-compression-mode
         (with-temp-buffer
           (prin1 content-header (current-buffer))
           (write-char ?\n (current-buffer))
@@ -722,7 +748,7 @@ Argument PENDING-LIST an `pending-undo-list' compatible 
list."
       (unless (file-exists-p undo-file)
         (throw 'exit nil))
 
-      (with-auto-compression-mode
+      (undo-fu-session--with-auto-compression-mode
         (with-temp-buffer
           (insert-file-contents undo-file)
           (goto-char (point-min))