# Objective
A common pitfall since 0.8 is the requirement on `ComputedVisibility`
being present on all ancestors of an entity that itself has
`ComputedVisibility`, without which, the entity becomes invisible.
I myself hit the issue and got very confused, and saw a few people hit
it as well, so it makes sense to provide a hint of what to do when such
a situation is encountered.
- Fixes#5849
- Closes#5616
- Closes#2277
- Closes#5081
## Solution
We now check that all entities with both a `Parent` and a
`ComputedVisibility` component have parents that themselves have a
`ComputedVisibility` component.
Note that the warning is only printed once.
We also add a similar warning to `GlobalTransform`.
This only emits a warning. Because sometimes it could be an intended
behavior.
Alternatives:
- Do nothing and keep repeating to newcomers how to avoid recurring
pitfalls
- Make the transform and visibility propagation tolerant to missing
components (#5616)
- Probably archetype invariants, though the current draft would not
allow detecting that kind of errors
---
## Changelog
- Add a warning when encountering dubious component hierarchy structure
Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com>
# Objective
- in #3851, a feature for tracing was added to bevy_transform
- usage of that feature was moved to bevy_hierarchy, but the feature was not updated
## Solution
- add the feature to bevy_hierarchy, remove it from bevy_transform
# Objective
- Hierarchy tools are not just used for `Transform`: they are also used for scenes.
- In the future there's interest in using them for other features, such as visiibility inheritance.
- The fact that these tools are found in `bevy_transform` causes a great deal of user and developer confusion
- Fixes#2758.
## Solution
- Split `bevy_transform` into two!
- Make everything work again.
Note that this is a very tightly scoped PR: I *know* there are code quality and docs issues that existed in bevy_transform that I've just moved around. We should fix those in a seperate PR and try to merge this ASAP to reduce the bitrot involved in splitting an entire crate.
## Frustrations
The API around `GlobalTransform` is a mess: we have massive code and docs duplication, no link between the two types and no clear way to extend this to other forms of inheritance.
In the medium-term, I feel pretty strongly that `GlobalTransform` should be replaced by something like `Inherited<Transform>`, which lives in `bevy_hierarchy`:
- avoids code duplication
- makes the inheritance pattern extensible
- links the types at the type-level
- allows us to remove all references to inheritance from `bevy_transform`, making it more useful as a standalone crate and cleaning up its docs
## Additional context
- double-blessed by @cart in https://github.com/bevyengine/bevy/issues/4141#issuecomment-1063592414 and https://github.com/bevyengine/bevy/issues/2758#issuecomment-913810963
- preparation for more advanced / cleaner hierarchy tools: go read https://github.com/bevyengine/rfcs/pull/53 !
- originally attempted by @finegeometer in #2789. It was a great idea, just needed more discussion!
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
