Cleanup: use const result in `ED_keyframes_find_*` functions.

source/blender/editors/animation/anim_draw.c

@@ -495,7 +495,7 @@ static bool find_prev_next_keyframes(struct bContext *C, int *r_nextfra, int *r_
   Mask *mask = CTX_data_edit_mask(C);
   bDopeSheet ads = {NULL};
   struct AnimKeylist *keylist = ED_keylist_create();
-  ActKeyColumn *aknext, *akprev;
+  const ActKeyColumn *aknext, *akprev;
   float cfranext, cfraprev;
   bool donenext = false, doneprev = false;
   int nextcount = 0, prevcount = 0;

source/blender/editors/animation/keyframes_keylist.c

@@ -72,26 +72,28 @@ void ED_keylist_free(AnimKeylist *keylist)
   MEM_freeN(keylist);
 }
 
-ActKeyColumn *ED_keylist_find_exact(const AnimKeylist *keylist, float cfra)
+const ActKeyColumn *ED_keylist_find_exact(const AnimKeylist *keylist, float cfra)
 {
-  return (ActKeyColumn *)BLI_dlrbTree_search_exact(&keylist->keys, compare_ak_cfraPtr, &cfra);
+  return (const ActKeyColumn *)BLI_dlrbTree_search_exact(
+      &keylist->keys, compare_ak_cfraPtr, &cfra);
 }
 
-ActKeyColumn *ED_keylist_find_next(const AnimKeylist *keylist, float cfra)
+const ActKeyColumn *ED_keylist_find_next(const AnimKeylist *keylist, float cfra)
 {
-  return (ActKeyColumn *)BLI_dlrbTree_search_next(&keylist->keys, compare_ak_cfraPtr, &cfra);
+  return (const ActKeyColumn *)BLI_dlrbTree_search_next(&keylist->keys, compare_ak_cfraPtr, &cfra);
 }
 
-ActKeyColumn *ED_keylist_find_prev(const AnimKeylist *keylist, float cfra)
+const ActKeyColumn *ED_keylist_find_prev(const AnimKeylist *keylist, float cfra)
 {
-  return (ActKeyColumn *)BLI_dlrbTree_search_prev(&keylist->keys, compare_ak_cfraPtr, &cfra);
+  return (const ActKeyColumn *)BLI_dlrbTree_search_prev(&keylist->keys, compare_ak_cfraPtr, &cfra);
 }
 
 /* TODO(jbakker): Should we change this to use `ED_keylist_find_next(keys, min_fra)` and only check
  * boundary of `max_fra`. */
-ActKeyColumn *ED_keylist_find_any_between(const AnimKeylist *keylist, const Range2f frame_range)
+const ActKeyColumn *ED_keylist_find_any_between(const AnimKeylist *keylist,
+                                                const Range2f frame_range)
 {
-  for (ActKeyColumn *ak = keylist->keys.root; ak;
+  for (const ActKeyColumn *ak = keylist->keys.root; ak;
        ak = (ak->cfra < frame_range.min) ? ak->right : ak->left) {
     if (range2f_in_range(&frame_range, ak->cfra)) {
       return ak;

source/blender/editors/armature/pose_slide.c

@@ -1716,7 +1716,7 @@ static float pose_propagate_get_boneHoldEndFrame(tPChanFCurveLink *pfl, float st
   /* Find the long keyframe (i.e. hold), and hence obtain the endFrame value
    * - the best case would be one that starts on the frame itself
    */
-  ActKeyColumn *ab = ED_keylist_find_exact(keylist, startFrame);
+  const ActKeyColumn *ab = ED_keylist_find_exact(keylist, startFrame);
 
   /* There are only two cases for no-exact match:
    *  1) the current frame is just before another key but not on a key itself
@@ -1746,7 +1746,7 @@ static float pose_propagate_get_boneHoldEndFrame(tPChanFCurveLink *pfl, float st
   if (ab) {
     /* Go to next if it is also valid and meets "extension" criteria. */
     while (ab->next) {
-      ActKeyColumn *abn = ab->next;
+      const ActKeyColumn *abn = ab->next;
 
       /* Must be valid. */
       if ((actkeyblock_get_valid_hold(abn) & ACTKEYBLOCK_FLAG_STATIC_HOLD) == 0) {

source/blender/editors/include/ED_keyframes_keylist.h

@@ -139,11 +139,11 @@ typedef enum eKeyframeExtremeDrawOpts {
 
 struct AnimKeylist *ED_keylist_create(void);
 void ED_keylist_free(struct AnimKeylist *keylist);
-struct ActKeyColumn *ED_keylist_find_exact(const struct AnimKeylist *keylist, float cfra);
-struct ActKeyColumn *ED_keylist_find_next(const struct AnimKeylist *keylist, float cfra);
-struct ActKeyColumn *ED_keylist_find_prev(const struct AnimKeylist *keylist, float cfra);
-struct ActKeyColumn *ED_keylist_find_any_between(const struct AnimKeylist *keylist,
-                                                 const Range2f frame_range);
+const struct ActKeyColumn *ED_keylist_find_exact(const struct AnimKeylist *keylist, float cfra);
+const struct ActKeyColumn *ED_keylist_find_next(const struct AnimKeylist *keylist, float cfra);
+const struct ActKeyColumn *ED_keylist_find_prev(const struct AnimKeylist *keylist, float cfra);
+const struct ActKeyColumn *ED_keylist_find_any_between(const struct AnimKeylist *keylist,
+                                                       const Range2f frame_range);
 bool ED_keylist_is_empty(const struct AnimKeylist *keylist);
 const struct ListBase /* ActKeyColumn */ *ED_keylist_listbase(const struct AnimKeylist *keylist);
 bool ED_keylist_frame_range(const struct AnimKeylist *keylist, Range2f *r_frame_range);

source/blender/editors/screen/screen_ops.c

@@ -3077,7 +3077,7 @@ static int keyframe_jump_exec(bContext *C, wmOperator *op)
   }
 
   /* find matching keyframe in the right direction */
-  ActKeyColumn *ak;
+  const ActKeyColumn *ak;
   if (next) {
     ak = ED_keylist_find_next(keylist, cfra);
   }