Merging meta from mixins doesn't work anymore

[Kapcash]

Description of the problem

I'm working on a Nuxt app and I just found out using head() from a mixins doesn't merge if the component using the mixin also declares a head().

-> Mixin and component meta function doesn't merge properly

Reproduction

Usable Codesandbox
Both index and about pages use the same mixins SeoMixin which declares the meta title and a canonical link.

• The index page doesn't have its own head method, so it has the meta info from the mixin as expected. (tab title is "Title from mixin")
• The about page has its own head method, and it doesn't merge with the mixin results (see the tab title)

Steps to reproduce

• Create a Vue mixins that declare a meta function (head, metaInfo or whatever depending on the configuration)
• Create a component that uses the mixin and declare its own meta function
• Both results from mixin + component are not merged

Notes

There were a similar issues before, which has been fixed by PR #262
But it looks like the last releases has introduced a regression for this.

I started adding a unit test on the code source to check it wasn't working.
I'll try to fix it myself as soon as I have time for this.

[stale]

Thanks for your contribution to vue-meta! This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you would like this issue to remain open:

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[pimlie]

Thanks for the report, this seems to be a very old regression indeed. As this seems to be an edge-case Im not sure if I will fix this, sorry. A PR is always welcome ofc!

[stale]

Thanks for your contribution to vue-meta! This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you would like this issue to remain open:

1. Verify that you can still reproduce the issue in the latest version of vue-meta
2. Comment the steps to reproduce it
   Issues that are labeled as pending will not be automatically marked as stale.