Relates to MC-224159, MC-226845 and MC-226846 as these also concern the absorption bar not having dedicated textures for certain situations.

The bug

The background "container" textures placed behind absorption hearts point to the same texture files that are used for the backgrounds of normal non-absorption hearts. This forbids resource pack creators from customizing the absorption heart container independently of the normal heart background, which is not ideal if a different shape is given to absorption hearts for example.

It's established that the absorption bar differs in function to other health bars due to factors such as the resolution of MC-206792, the usage of separate textures for hearts, fully empty hearts outright disappearing from the bar and so on, so it'd be expected that a separate (if visually identical) background texture would be used like is the case for horse hearts and hardcore hearts, but this does not happen.

How to reproduce

A resource pack is attached to this issue that only changes the textures "container.png" and "container_blinking.png" in the texture directory gui/sprites/hud/heart.

1. Download and apply the attached resource pack
2. Eat a golden apple in a non-Hardcore survival world
3. Observe

Expected results

As container.png and container_blinking.png have been modified, the hearts on the normal health bar would have a different looking background, but the absorption hearts would not.

Actual results

The normal health bar heart background textures are changed as expected, but so are the absorption heart background textures, which should not happen.

How to fix

Two textures would be introduced to gui/sprites/hud/heart: one called "absorbing_container.png" and another called "absorbing_container_blinking.png", which would be duplicates of the existing "container.png" and "container_blinking.png" textures respectively but used for absorption hearts instead of normal hearts.

As a proof of concept, I've attached four concept sprites for this purpose instead of two: "absorbing_container_half.png" and "absorbing_container_half_blinking.png" would be used for half-hearts due to the fact that full hearts are deducated from the absorption bar when lost - these containers would reflect that fact rather than leaving an empty half behind as it does currently.