Fix multiplicative observation of controllers in views

[trentmwillis]

Addresses issue #12016.

Root cause: when the controller changed for a view, it would notify all of it's descendant views which would in turn notify all of their descendant views resulting in a multiplication of work, especially when many descendants are involved.

Solution: when the controller changes for a view, only notify it's immediate children.

[stefanpenner]

Note: I haven't added a test for this yet, as I wasn't sure if I should since this is marked as legacy behavior at this point. Can add it if needed.

A test would be ideal, that way if we find a regression or need to build on it, we have some confidence in our changes.

Thank you for digging into this.

[trentmwillis]

@stefanpenner added a test and verified it failed before this fix.

[stefanpenner]

@trentmwillis very nice, thank you for taking the time.

@wycats @ef4 @tomdale @krisselden I would love to double check this solution with one of you

[ef4]

Looks good to me.

[stefanpenner]

Oops. These should have been bugfix release....

@rwjblue paging you to fix my mistake :p

[rwjblue]

@stefanpenner - release or release-1-13?

[ef4]

I would favor release-1-13, unless there is some hurdle that makes the backport nontrivial.

[stefanpenner]

I would favor release-1-13, unless there is some hurdle that makes the backport nontrivial.

[green-arrow]

@stefanpenner or @ef4 - was this put in a 1.13 release? I was looking through the changelog and didn't see this issue referenced anywhere.

[rwjblue]

Yeah, I missed this (since it didn't have a commit prefix).

[rwjblue]

Just pushed to release-1-13 branch. Assuming that the Travis build passes properly, the builds will be available from bower via "ember": "release-1-13" in a few minutes.

[green-arrow]

Thanks for that @rwjblue. I'll make sure to pull that down and give it a look once the build goes through.

[green-arrow]

@rwjblue - pulled down that release and all is working well. At least the issue I was having with these transitions are resolved 😄

[green-arrow]

@rwjblue any idea when this will be cut in a 1.13 release? Not sure if you were waiting on anything else before cutting a release.

[rwjblue]

I don't see a bunch of value in tagging for just one change, when the builds (both S3 and bower) are available. I generally batch a few changes up before releasing...

[green-arrow]

That's fair. I'll just continue with the release-1-13 build then. Thanks again!

[pavloo]

I confirm that this fixed my problem with poor rendering performance of the component in the app I was working on.