Engine routes deactivated after destruction

[trentmwillis]

In 2.8.0, there was a change introduced to the order of teardown when Engines are involved. The change in question seems to have fixed another issue, but causes routes in Engines to be destroyed prior to their deactivate hook being run (during the Router's reset).

This means that if you do something such as set a property on the Route during deactivate, then errors will propagate in Acceptance tests.

Unsure what the proper fix is here. Seems like maybe only the views from the Engines should be torn down prior to resetting the Router.

(Here's the prior implementation from the ember-engines addon.)

cc @asakusuma @krisselden

[rwjblue]

@trentmwillis - Can you work up a failing test (best harness ATM for this is here)?

[trentmwillis]

@rwjblue reproduction added in #14237.

[trentmwillis]

@rwjblue / @asakusuma do you know if the original issue:

Ensure that engines are destroyed before top-level views so that top-level views are not re-instantiated during engine teardown.

Had tests to catch a regression? Because I looked into fixing this and just switching the order back seems to pass without failing any tests.

[rwjblue]

@trentmwillis - Yeah, I think the isDestroying guard added in #14123 actually fixed the regression (just before the PR changing the order landed).

[trentmwillis]

@rwjblue okay, so do you think switching the order back seems like the proper solution? If so, I'll update my PR with the failing test.

[rwjblue]

@trentmwillis - Yeah, lets switch it back and confirm tests pass.

[trentmwillis]

Fixed via #14237. Tested against the latest release build.