[3.17.0 beta regression] Array Proxy not updating

[patocallaghan]

I've found what appears to be a regression with ArrayProxy that was introduced in this commit #18703 in 3.17.0-beta.3. 3.17.0-beta.2 is working as expected.

These changes were also backported in #18721 to 3.16.2 which means the regression is also on 3.16.2, but works on 3.16.1.

I've got a reproducing test in my repo here. While the test is a bit convoluted this is a bare bones reproduction of some code in our app where we are seeing the issue.

https://github.com/patocallaghan/array-proxy-regression/blob/master/tests/unit/array-proxy-test.js

It seems that modifying the ArrayProxy internally is not picking up all the changes.

/cc @pzuraq

[pzuraq]

Thanks for this thorough bug report! I have a reproduction with a unit test locally, very strange. Will be taking a look as soon as I have time.

[rwjblue]

Closed by #18770

[DuBistKomisch]

Any plans to backport this fix to 3.16(.4)?

[pzuraq]

Yes, the fix is marked for release. We are currently waiting to make sure it works as expected and doesn’t cause further issues.

[jonathannewman]

Any update on plans to backport this to 3.16?

[deanylev]

Seems this wasn't backported to 3.16.4? :/

[jonathannewman]

I just tried the new 3.16.5 against our codebase and am still seeing the failures related to this in our tests. @pzuraq @rwjblue any chance of getting this fix in? We would like to update to the 3.16 LTS.

[pzuraq]

I’m working on it today

[rwjblue]

Ya, I chatted with @pzuraq about this last night. I wanted to get the other fixes out (fixing an issue with Babel 7.9.x, and an observer memory leak issue), and @pzuraq is going to work on backporting the fix for this into lts-3-16 branch today and we'll get yet another patch release out (hopefully today). Good news though: we won't run out of numbers! 😃

[jonathannewman]

Awesome! Thank you!