New YAML engine writes invalid yaml arrays

[nesl247]

With the new yaml engine in 2.24.0, previously written valid yaml is rewritten in invalid yaml when running pulumi config set. The invalid yaml are arrays, however, this is triggered by updating anything in the file. It's only necessary to trigger pulumi to rewrite the file to cause the problem.

Expected behavior

This is a subsection of our Pulumi.staging.yaml file.

    unvailablePods:
      configuration:
        notifyTargets:
          - '@some-target'
        priorities:
          critical: P3

Current behavior

This is a subsection of our Pulumi.staging.yaml file.

    unvailablePods:
      configuration:
        notifyTargets:
        - @some-target
        priorities:
          critical: P3

Steps to reproduce

1. Use pulumi 2.24.0
2. Have a config that has an array of strings
3. Use pulumi config set to change any value in the configuration (it does not need to be related to the array at all)
4. The array is rewritten in invalid yaml

Context (Environment)

This occurs using pulumi 2.24.0.

Affected feature

Our deployment pipeline got broken by this as pulumi is writing invalid yaml. We had to revert to a fixed version pointing to the previous release.

[mikhailshilkov]

@lblackstone this sounds like a nasty issue, could you please take a look?

[lblackstone]

This must be a bug in the new YAML package because #6489 hasn't merged yet. I'll see about getting this fixed today.

[lblackstone]

We decided to revert the package change for now until we can make sure this is fixed. We'll cut a patch release ASAP.

[stack72]

Hi @nesl247

As a follow up to what @lblackstone said, I am cutting v2.24.1 release right now

Paul

[stack72]

Hey @nesl247 this is closed via #6689

[nesl247]

Thanks @stack72 and @lblackstone.