call order for didInsertElement for siblings reversed

[KoKuToru]

Example:

{{my-component name="A"}}
{{my-component name="B"}}
{{my-component name="C"}}
{{my-component name="D"}}

order of didInsertElement hooks: A B C D

in 2.9.0-alpha+8ba7f68f the order is now: D C B A

Ember-Twiddle: https://ember-twiddle.com/#/847f6adf7c7dc53f65f449062c3c5549 (output in console)

I have some code that depends on the order of didInsertElement.
willInsertElement is still in the right order.

[rwjblue]

Hmm. I don't think the order of didInsertElement for siblings was a really well defined API. We definitely guarantee that any child components' didInsertElement is called before their parents, but I don't think we have made guarantees on the ordering of A, B, C, D in your example.

@krisselden - You likely know this area the best, what do you think? Should we consider this a bug and try to fix it, or is the Glimmer@2 behavior intentional?

[chancancode]

I think we did it to pass tests: 1581583#diff-c8938eb5cb17b733982744e1621cb8e4R168

If the actual goal is to have the children called before the parent, I think the would be pretty simple; instead of queuing the hooks in OpenComponentOpcode, we could move it to CloseComponentOpcode, then we can delete the patch in Ember that reverses the order, and everything should just work.

Are the rules the same for update hooks? I don't know if there is an equivalent place for it now, but we can make CloseComponentOpcode emit a corresponding updating opcode to queue the hook.

[rwjblue]

@chancancode - The parent/child ordering is correct. This issue is about siblings.

[chancancode]

Yeah. Basically we did pre-order queueing (Parent - Child 1 - Child 2 - Child 3) and then the test failed, so we just reversed the order to make it pass (C3 C2 C1 P).

If we actually want post-order queuing (C1 C2 C3 P), I think we can actually do it. Might have some implications for exception cases though, since if it errored when appending one of your children, your hook will not be queued/called, but that whole area needs a lot more love anyway.

[krisselden]

I don't think it is strictly a bug, but it feels bad.