Prune animation cache when images are no longer reachable

* lisp/image.el (image-animate-timeout): Eject cached animated
images that are no longer reachable (bug#56546).

* src/image.c (Fclear_image_cache): Allow specifying a cached
animated image to eject.
(gif_load, webp_load): Adjust what to use as the caching key --
the identity of the list itself is apparently changed by some
callers.

1 files changed, 11 insertions, 4 deletions

diff --git a/lisp/image.el b/lisp/image.el
index bdaaec608ef..f4f73fd31f2 100644
--- a/lisp/image.el
+++ b/lisp/image.el
@@ -966,9 +966,10 @@ for the animation speed.  A negative value means to animate in reverse."
   (plist-put (cdr image) :animate-tardiness
              (+ (* (plist-get (cdr image) :animate-tardiness) 0.9)
                 (float-time (time-since target-time))))
-  (let ((buffer (plist-get (cdr image) :animate-buffer))
-        (position (plist-get (cdr image) :animate-position)))
-    (when (and (buffer-live-p buffer)
+  (let* ((buffer (plist-get (cdr image) :animate-buffer))
+         (position (plist-get (cdr image) :animate-position))
+         (continue-animation
+          (and (buffer-live-p buffer)
                ;; If we have a :animate-position setting, the caller
                ;; has requested that the animation be stopped if the
                ;; image is no longer displayed in the buffer.
@@ -985,7 +986,13 @@ for the animation speed.  A negative value means to animate in reverse."
                (or (< (plist-get (cdr image) :animate-tardiness) 2)
                    (progn
                      (message "Stopping animation; animation possibly too big")
-                     nil)))
+                     nil)))))
+    (if (not continue-animation)
+        ;; Eject from the animation cache since we've decided not to
+        ;; keep updating it.  This helps stop unbounded RAM usage when
+        ;; doing, for instance, `g' in an eww buffer with animated
+        ;; images.
+        (clear-image-cache nil image)
       (let* ((time (prog1 (current-time)
                      (image-show-frame image n t)))
              (speed (image-animate-get-speed image))