Named routing substates have never worked for nested routes.

[nathanhammond]

Named routing substates (#3655) haven't ever properly accounted for route nesting. I've forked @machty's original JS Bin from before this feature was introduced to demonstrate broken nested behavior here.

Reproduction:

• Click "Try again"
• Click "nested route"
• Click "nested sibling"

The last transition shows that navigation between two nested sibling routes does not trigger the global loading state as the "most specific" loading state in the hierarchy. This conflicts with his description in the JS Bin, as well as the docs we had at approximately that time.

According to our documentation the expected behavior is full bubbling, grabbing the leaf-most error or loading substate. This behavior is different again in 2.3+, presumably as a consequence of the owners change.

I propose (and volunteer) to actually make this behavior match our documentation and function as expected. This is a "breaking" change, but is also a bugfix.

/cc @machty @alexspeller

[nathanhammond]

parent/child/grandchild => parent/otherchild/othergrandchild

Priority:

1. parent/otherchild_loading || parent/loading
2. parent/otherchild
3. parent/otherchild/othergrandchild_loading || parent/otherchild/loading
4. parent/otherchild/othergrandchild

[nathanhammond]

parent/child/grandchild => parent/otherchild/boom

Priority:

1. parent/otherchild_loading || parent/loading
2. parent/otherchild
3. parent/otherchild/boom_loading || parent/otherchild/loading
4. parent/otherchild/boom => error

Error handling:

1. parent/otherchild/boom_error
2. parent/otherchild/error
3. parent/otherchild_error
4. parent/error
5. parent_error
6. error
7. application_error

[ShogunPanda]

+1 - Please fix this!

[machty]

@nathanhammond can you provide an update? I believe when we were going through this on the community Slack, everything was behaving as expected (just that perhaps things are poorly documented / unclear?)

[nathanhammond]

I'm still writing tests make sure that this works. my current belief is that it is implemented correctly.