Vue-Mobx integration broken with PR #7828

Thanks for mentioning me, the other option that I think would be doable is to change mobx itself so that it would allow setting proto for an array. The problematic code is in arrayTraps.set function:
I'm not sure of the impact of such a change though.
Either way, it would be nice to have test(s) that are run as part of the test suite to verify the mobx integration. I think they should go into the mobx-vue repo but they would need to be triggered whenever a new minor version of vue and/or mobx is released. That might not be trivial to do.

Good point @Nemikolh - I have no context for which might be the better place to fix this. I followed the Vue path because that's the package that appeared to break. Maybe core Vue and/or Mobx contributors will have an opinion (that is compatible😜). It does seem that tests would be well placed in mobx-vue.

what is the actual thing breaking Vue, without any mobx/mobx-vue import?

Hi @posva, to be honest, probably nothing; but neither is anything broken in Mobx unless you try to use Vue - so I'm a bit at a loss as to how to proceed 😞 With my personal apps (using Vue and Vuex) nothing is wrong. When I'm working with my employers app (Vue, Mobx, MST) this function:

function protoAugment (target, src: Object) {
  /* eslint-disable no-proto */
  target.__proto__ = src
  /* eslint-enable no-proto */

in vue/src/core/observer/index.js invokes the Mobx set on observable arrays and returns false (causing the vue warning). forked the Mobx repo and added a check to the end of the set function:

        if (name === "__proto__") {
            return true
        return false

But I have a really bad feeling about that as I have no idea what I might be breaking in Vue. It looks like Vue is trying to hook into the prototype chain to observe changes, but Mobx is already doing that. So, I don't know what the answer is.