$listeners is readonly error

[eddyerburgh]

Version

1.0.0-beta.14

Reproduction link

https://codesandbox.io/s/0y2o4p8zvv

Steps to reproduce

Visit reproduction link.

What is expected?

Should not warn

What is actually happening?

Warn that $listerns and $attrs is readonly

[tbsvttr]

@eddyerburgh Same problem here. Happened directly after upgrading from vue-test-utils Beta 12 to Beta 13! However, the problem stayed after upgrading from Beta 13 to Beta 14.

[timoschwarzer]

Might be related to #534

[eddyerburgh]

This is caused by the changes in beta.12 where we set all watchers to sync.

We set all watchers to sync, including the update watcher. This causes a re-render when the comonent updates the attrs. Then before the listeners have been updated, isUpdatingChildComponent is set to false, so when the listeners are mutated, the warning is logged.

[bdeo]

Is there a workaround for this/plan to resolve? I've confirmed this with Element-UI as well. I don't think this is Vuetify specific. Maybe title should remove Vuetify specifically. https://codesandbox.io/s/q377x6prx9

[eddyerburgh]

The plan to resolve is to add an async option to Vue that we will set to false. I have a PR open but it won't be added until Vue 2.6 in a months time.

The only solution I can think of for this issue is to set Vue to silent when running update watchers:

Vue.config.silent = true

You can see more info on the synchrnous issue —#676

[ticdenis]

How can I silence these warnings?

[wordythebyrd]

@ticdenis, I believe @eddyerburgh is recommending you set Vue to silent. See the documentation.

Vue.config.silent = true

Suppress all Vue logs and warnings.