How do you merge arrays of objects together matching on a key

[richard24se]

Describe the bug
A clear and concise description of what the bug is.

Note that any how to questions should be posted in the discussion board and not raised as an issue.

Version of yq: 4.7.1
Operating system: linux
Installed via: binary

Input Yaml
Concise yaml document(s) (as simple as possible to show the bug, please keep it to 10 lines or less)
s1.yml:

rules:
  - host: hooks.pe
    http:
      paths:
      - backend:
          serviceName: tes1
          servicePort: 5005
        pathType: ImplementationSpecific
  - host: hooks.pe2
    http:
      paths:
      - backend:
          serviceName: test2
          servicePort: 50052
        pathType: ImplementationSpecific
rules2:
  - host: hooks.pe2
    http:
      paths:
      - backend:
          serviceName: tes1
          servicePort: 5010
        pathType: ImplementationSpecific

Command
The command you ran:

yq eval '.rules *d .rules2' s1.yml

Actual behavior

- host: hooks.pe2
  http:
    paths:
      - backend:
          serviceName: tes1
          servicePort: 5010
        pathType: ImplementationSpecific
- host: hooks.pe2
  http:
    paths:
      - backend:
          serviceName: test2
          servicePort: 50052
        pathType: ImplementationSpecific

Expected behavior

- host: hooks.pe
  http:
    paths:
      - backend:
          serviceName: test1
          servicePort: 5005
        pathType: ImplementationSpecific
- host: hooks.pe2
  http:
    paths:
      - backend:
          serviceName: test1
          servicePort: 5010
        pathType: ImplementationSpecific

Additional context

[mikefarah]

That's how merge with the deep flag is supposed to work. You have two arrays, each containing objects - it merges the objects deeply in the matching indices.

Note: there is no way for yq to know the schema of the objects being merged, and further that the 'host' key on the objects are keys that should be matched.

[mikefarah]

Had more of a think about this, and there is a way to do it - albeit the command is tricky. I've added a guide here:

https://mikefarah.gitbook.io/yq/operators/multiply-merge#merge-arrays-of-objects-together-matching-on-a-key

[Update moved guide to go into merge docs]

[richard24se]

That's surprise. Well I've doing a tool with Python. This was born cause I use k8s ingress. But Thank you. I will try with your amazing tool.

[richard24se]

Hello. In the example key a with value dingo is lost. How would add? Thank you

[mikefarah]

Right so the example is updating each element of the first array with matching elements of the second. Extra items in the first array will survive..but yeah extras in the second won't

Hmmmm...not sure