# Objective
Recently the `u32` `Entity::generation` was replaced with the new
`EntityGeneration` in #19121.
This made meanings a lot more clear, and prevented accidental misuse.
One common misuse was assuming that `u32`s that were greater than others
came after those others.
Wrapping makes this assumption false.
When `EntityGeneration` was created, it retained the `u32` ordering,
which was useless at best and wrong at worst.
This pr fixes the ordering implementation, so new generations are
greater than older generations.
Some users were already accounting for this ordering issue (which was
still present in 0.16 and before) by manually accessing the `u32`
representation. This made migrating difficult for avian physics; see
[here](https://discord.com/channels/691052431525675048/749335865876021248/1377431569228103780).
I am generally of the opinion that this type should be kept opaque to
prevent accidental misuse.
As we find issues like this, the functionality should be added to
`EntityGeneration` directly.
## Solution
Fix the ordering implementation through `Ord`.
Alternatively, we could keep `Ord` the same and make a `cmp_age` method,
but I think this is better, even though sorting entity ids may be
*marginally* slower now (but more correct). This is a tradeoff.
## Testing
I improved documentation for aliasing and ordering, adding some doc
tests.
1966e44400