Warning spam about "Could not determine track hint" for modulate:a animation tracks

[romlok]

Tested versions

• Reproducible in: v4.3.dev6.official [64520fe]
• Reproducible in: v4.2.stable.official [46dc277]
• Not reproducible in: v4.1.4.stable.official [fe0e8e5]

System information

Debian GNU/Linux trixie/sid trixie - Wayland - Vulkan (Forward+) - dedicated AMD Radeon RX 7600 (RADV NAVI33) () - AMD Ryzen 5 7600 6-Core Processor (12 Threads)

Issue description

If one has an animation track for just the alpha of a CanvasItem.modulate property (eg. .:modulate:a), selecting the AnimationPlayer in the scene tree will cause several (3-5) warnings to be sent to the output panel:

editor/animation_track_editor.cpp:4315 - Could not determine track hint for '.:modulate:a' because its base property is null.

The animation itself appears to function as expected.

---

Possibly related to #83421, since the connected PR #84129 introduced this warning message. However that issue seems to relate more specifically to an error when animating shader parameters.

Also, the same warning was mentioned in #90435, but since that is closed as fixed, appears to have been unrelated/tangential to that issue's error.

Steps to reproduce

1. Create a CanvasItem-derived node (eg. Node2D)
2. Create an AnimationPlayer
3. Add a new animation
4. Add an animation track for the CanvasItem's modulate property
5. On the animation track, edit the track's path (eg. click the modulate text) and add :a at the end
6. Check the output bottom panel 👀

Alternatively, open the MRP and select the AnimationPlayer

Minimal reproduction project (MRP)

animate-modulate-a-warning.zip