The behaviour should be the same between the two examples.
Actual behavior
The presence of a reactive variable on the <router-view> in the Vue 3 version forces its descendants' watchers to update. I believe the correct behaviour should be the Vue 2.7 behaviour.
Reproduction
https://jsfiddle.net/sj1chxmd/2/
Steps to reproduce the bug
Observe behaviour in this repro (Vue 2.7): https://jsfiddle.net/sj1chxmd/2/ Then compare the behaviour in this repro (Vue 3): https://jsfiddle.net/sf2gutkr/1/
Expected behavior
The behaviour should be the same between the two examples.
Actual behavior
The presence of a reactive variable on the
<router-view>
in the Vue 3 version forces its descendants' watchers to update. I believe the correct behaviour should be the Vue 2.7 behaviour.Additional information
Related: