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List Join / Split

Two mirrored strategies: listJoin (hub array of scalars → spoke delimited string) and listSplit (hub delimited string → spoke array of scalars). Functionally identical — which name you use just depends on which side is the array in your schemas.

What it does

Converts an array of scalars into a single string by joining its (string-coerced) elements with a separator, and splits that string back into an array on the reverse direction.

When to use it

An older (or simpler) API version stores a list as a single delimited string ("8.8.8.8,1.1.1.1"), while a properly-typed version uses a real array.

Always lossless — with one caveat

Both directions round-trip exactly, provided no element of the array contains the separator character as a substring. If it does, joining and re-splitting won't reproduce the original array shape — convctl test correctly surfaces this as a genuine data problem for whatever sample triggered it, not as an expected characteristic of the strategy to acknowledge in the config.

Example: listJoin

The hub's dnsServers array becomes a comma-joined string on the v2 spoke:

spec:
  properties:
    dnsServers:
      type: array
      items:
        type: string

spec:
  properties:
    dnsServersCSV:
      type: string

Rule

- strategy: ListJoin
  listJoin:
    hubPath: spec.dnsServers
    spokePath: spec.dnsServersCSV
    separator: ","

Objects

spec:
  dnsServers:
    - "8.8.8.8"
    - "1.1.1.1"

spec:
  dnsServersCSV: "8.8.8.8,1.1.1.1"

Example: listSplit

The mirror image, with the roles of hub and spoke reversed — the hub holds the delimited string, the spoke holds the array:

spec:
  properties:
    allowedCIDRsCSV:
      type: string

spec:
  properties:
    allowedCIDRs:
      type: array
      items:
        type: string

Rule

- strategy: ListSplit
  listSplit:
    hubPath: spec.allowedCIDRsCSV
    spokePath: spec.allowedCIDRs
    separator: ","

Objects

spec:
  allowedCIDRsCSV: "10.0.0.0/8,192.168.0.0/16"

spec:
  allowedCIDRs:
    - "10.0.0.0/8"
    - "192.168.0.0/16"

listJoin and listSplit are the same underlying operation; use whichever name matches which side (hub or spoke) is the array in your particular schema pair.