Support YAML tags within docker compose files

[websi]

Tell us more.

Docker compose support following tags (https://docs.docker.com/reference/compose-file/merge/):

• reset
• override

This is not supported by renovate by now. See error message.
For a project with multiple docker compose files this is a really nice feature to prevent configuration duplication.
Without these feature, we can not update our projects with renovate with such complex docker compose files.

DEBUG: Parsing Docker Compose config YAML failed (repository=..., packageFile=docker-compose.production.yml)
       "err": {
         "name": "YAMLException",
         "reason": "unknown tag !<!reset>",
         "mark": {
           "name": null,

Maybe here the solution from gitlabci helps https://github.com/renovatebot/renovate/blob/main/lib/modules/manager/gitlabci/utils.ts#L13

See also #31073

Minimal reproduction repo: https://github.com/websi/renovate-reproductions-31147
Renovate run: f3b23e52-337f-4d56-b282-8edcd366b18d

[github-actions[bot]]

Hi there,

Get your discussion fixed faster by creating a minimal reproduction. This means a repository dedicated to reproducing this issue with the minimal dependencies and config possible.

Before we start working on your issue we need to know exactly what's causing the current behavior. A minimal reproduction helps us with this. Discussions without reproductions are less likely to be converted to Issues.

Please follow these steps:

1. Read our guide on creating a minimal reproduction.
2. Go to our minimal reproduction template repository.
3. Select the Use this template button to create a new repository based on the template.
4. Work on the minimal reproduction in your own repository.
5. Fill out the information in your repository's README.md.
6. Add the link to your reproduction to the first post of your Discussion. If you are not the original author, you can post a new comment with the link.

Good luck,

The Renovate team

[websi]

I will provide an PR for that. Maybe i found a generic solution. See #31200

[websi]

See #31244

It seems that the !!merge tag is not supported by the used library js-yaml at the moment.
See nodeca/js-yaml#697 and nodeca/js-yaml#697

[websi]

Solved by #31336