fix(ssr): v-show directive does not work for SSR when value changes before hydration

[kedrzu]

Let us suppose we have a component with a v-show directive that is wrapped with transition and rendered with SSR.
Initially v-show value is false so in SSR element is rendered with display: none.

Then SSR generated content is hydrated in browser. By the time component gets hydrated value changes from false to true. It may happen for example because the component is asynchronously loaded, or there are minor differences in server and client generated vdom.

What is happening now, is that style display does not get updated upon mounting the component.

Reproduction:
https://codesandbox.io/s/hardcore-hermann-8nst6p?file=/src/App.vue

[edison1105]

duplicate of #6123 ?

[kedrzu]

It may be the case.
The condition is transition && value, so it would not correctly update style if:

• element is initially hidden, transition is not null and value is true (which is my case)
• element is initially shown and value is false (which is the case in link)

[edison1105]

Closing as fixed via 98b83e8