Fix errors and improve UX relating to new animation libraries

- Fix a bug causing an error message when a scene containing an AnimationPlayer with a reset track is saved, by correctly referencing the temporary "default" library.
- Make library dropdown in new animation window assign correct library when creating an animation.
- Similarly allow choice of library when duplicating animation.
- Make library dropdown default to library of currently selected animation.
- Make library dropdown show when exactly one library exists, and it isn't [Global]. Include [Global] on the dropdown in this case (will be newly created if dialog is confirmed).
- When appending (x) to avoid New Anim name collisions, correctly check target library instead of [Global].
- Add parentheses when appending x when duplicating animations in the library editor, for consistency.
- Change titles and prompts to be distinct in name/rename/duplicate dialiogs.
- Fix bug in OprionButton.get_selectable_item(true) when last is not selectable.
- Fix issues where animation wasn't found on deletion/rename by correctly prepending library name.
- Remove an extraneous print_line from animation_track_editor.
- Add messages to errors when an animation isn't found.

1 files changed, 3 insertions, 3 deletions

diff --git a/scene/resources/animation_library.cpp b/scene/resources/animation_library.cpp
index 2a581fb126..361bfd0cb3 100644
--- a/scene/resources/animation_library.cpp
+++ b/scene/resources/animation_library.cpp
@@ -63,7 +63,7 @@ Error AnimationLibrary::add_animation(const StringName &p_name, const Ref<Animat
 }
 
 void AnimationLibrary::remove_animation(const StringName &p_name) {
-	ERR_FAIL_COND(!animations.has(p_name));
+	ERR_FAIL_COND_MSG(!animations.has(p_name), vformat("Animation not found: %s.", p_name));
 
 	animations.erase(p_name);
 	emit_signal(SNAME("animation_removed"), p_name);
@@ -71,9 +71,9 @@ void AnimationLibrary::remove_animation(const StringName &p_name) {
 }
 
 void AnimationLibrary::rename_animation(const StringName &p_name, const StringName &p_new_name) {
-	ERR_FAIL_COND(!animations.has(p_name));
+	ERR_FAIL_COND_MSG(!animations.has(p_name), vformat("Animation not found: %s.", p_name));
 	ERR_FAIL_COND_MSG(!is_valid_animation_name(p_new_name), "Invalid animation name: '" + String(p_new_name) + "'.");
-	ERR_FAIL_COND(animations.has(p_new_name));
+	ERR_FAIL_COND_MSG(animations.has(p_new_name), vformat("Animation name \"%s\" already exists in library.", p_new_name));
 
 	animations.insert(p_new_name, animations[p_name]);
 	animations.erase(p_name);