Quasar: Unnecessary re-renders Q-components

[alexdee2007]

Describe the bug
Useless re-renders of components on parent update

Codepen/jsFiddle/Codesandbox (required)
https://codepen.io/alexdee2007/pen/LYpObve

To Reproduce
Steps to reproduce the behavior:

1. Open console
2. Enter some text into field "Text1" -> Vue re-renders all four q-inputs as well as q-btn

Expected behavior
In console:

"updated" "Text1"

What is actually happening?
In console:

"updated" "Text1"
"updated" "Text2"
"updated" "Text3"
"updated" "Text4"
"updated" "Button"

Platform (please complete the following information):
OS:
Node:
NPM:
Yarn:
Browsers:
iOS:
Android:
Electron:

Additional context
Using $listeners and/or $attrs in component's render function causes the component to be rendered whenever its parent is updated even though his props hasn't changed.
It causes high performance impact when using e.g. form with a lot of q-inputs.

Related to https://github.com/vuejs/vue/issues/7257 and https://github.com/vuejs/vue/issues/10115

There are workarounds, e.g. vuetify or bootstrap-vue

[rstoenescu]

Hi, we actually noticed this too and were preparing a workaround.

[rstoenescu]

Perf improvements will be available in "quasar" v1.10.1.