[Bug] String with value "null" and empty string in custom arguments are wrongly serialized

[Vampire]

Action

Use these custom arguments for a job:

_customArguments = mapOf(
    "strategy" to mapOf(
        "matrix" to mapOf(
            "distribution" to listOf(
                mapOf(
                    "id" to "invalid",
                    "label" to "invalid"
                ),
                mapOf(
                    "id" to "",
                    "label" to ""
                ),
                mapOf(
                    "id" to null,
                    "label" to "null"
                )
            )
        )
    )
)

Expected

strategy:
    matrix:
        distribution:
            - id: invalid
              label: invalid
            - id: ''
              label: ''
            - id: null
              label: 'null'

Actual

strategy:
  matrix:
    distribution:
    - id: invalid
      label: invalid
    - id:
      label:
    - id: null
      label: null

which is semantically the same as

strategy:
  matrix:
    distribution:
    - id: invalid
      label: invalid
    - id: null
      label: null
    - id: null
      label: null

Library version

v0.34.2

[krzema12]

Thanks for reporting!

For completeness, we'll also need to allow nulls as top-level values for custom arguments.

[Vampire]

Definitely :-)