Renovate doesn't update docker-compose with yaml anchors anymore

[rarkins]

Discussed in #32918

^{Originally posted by mueller-ma December 5, 2024}

How are you running Renovate?

A Mend.io-hosted app

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

No response

Please tell us more about your question or problem

In the past Renovate had no problems when a Docker compose file had yaml anchors. Now it doesn't extract the image anymore:

• https://github.com/mueller-ma/renovate-reproduce/blob/main/docker-compose.yml
• Dependency Dashboard mueller-ma/renovate-reproduce#2

docker compose can use and parse this docker-compose file. You can see that docker includes the image in both services:

$ docker compose -f docker-compose.yml config
name: tmp
services:
  service-a:
    environment:
      SERVICE: a
    image: debian:11
    networks:
      default: null
  service-b:
    environment:
      SERVICE: b
    image: debian:11
    networks:
      default: null
networks:
  default:
    name: tmp_default
x-shared_setting:
  image: debian:11

Logs (if relevant)

Logs

DEBUG: packageFiles with updates
{
  "baseBranch": "main"
  "config": {
    "docker-compose": [
      {
        "deps": [],
        "packageFile": "docker-compose.yml"
      }
    ]
  }
}

Reproduction: renovate-reproductions/32918

[vic1707]

As added context extracted from the discussion

it appears that adding

%YAML 1.1
---

At the top of the file help get back some anchors capabilities.

With the fix, merging maps seems to be parsed correctly
working example:

%YAML 1.1
---
x-GICKUP: &GICKUP
    image: docker.io/buddyspencer/gickup:0.10.36

services:
    gickup:
        <<: *GICKUP

while using a scalar alias for a single value instead of merging a mapping doesn't work.

%YAML 1.1
---
x-GICKUP: &GICKUP docker.io/buddyspencer/gickup:0.10.36

services:
    gickup:
        image: *GICKUP