Version

3.0.0-rc.10

Reproduction link

https://jsfiddle.net/skirtle/f78Lhcmt/

Steps to reproduce

The important section is this:

<my-child abc="specific" v-bind="{ abc: 'object' }" />

Note that abc is set in two different ways.

What is expected?

In Vue 2 the value of abc would have been 'specific'.

What is actually happening?

abc is 'object'.

The order of the attributes now matters.

I also experimented with using :abc for the first attribute but it doesn't seem to matter whether the prop is static or dynamic.

I know this topic has been discussed several times before but I haven't been able to find any official confirmation that this has been changed intentionally.

A look through the tests seems to suggest that this is being tested, so my guess is that it is an intentional change.

The most recent discussion I could find on this topic was 3 weeks ago. vue#11594. While that was a discussion about Vue 2 it does seem odd that the change in Vue 3 wasn't mentioned if it is indeed an intentional change.

Yes, this is an intentional change (v-bind appearance order now affects merge result) and we should document it in the migration guide.

I have suggested a change that might be able to fix that: https://github.com/vuejs/rfcs/pull/215