validate field if and only if "when" condition applies

[pauko]

I have a field called superseded_by which is configured with a when condition that says "when field state equals value superseded".
In addition I want to model the semantics, if "state is superseded" that field superseded_by is mandatory (hence, required: true).

In the FrontMatter sidebar superseded_by is visible if and only if state: superseded (which goes with the intended semantics), however in the frontmatter of the markdown file the field superseded_by is already there upon content creation, even if the initial state doesn't hold that value superseded. Moreover, FrontMatter marks that field as erroneous, because it has no meaningful value yet, although at this point of time I don't want superseded_by to be validated at all - because that when condition is not fulfilled at all.

If I delete the superseded_by field manually, the error goes away.

Is there a way to:

• either model my semantics properly so that this field is only validated if the corresponding when condition applies?
• or prevent the field from being added into the front matter of the markdown file upon creation of the content?

[estruyf]

Thanks, @pauko, for opening this question. It might just be an issue, and we'll have to work to get this supported.

[estruyf]

Would you be able to share your configuration?

By default, on content creation, it will add all fields. As I understand, this is not something you want; what you can do is, on the content type, set the clearEmpty property as true, which makes sure to remove the empty fields.

{
  "frontMatter.taxonomy.contentTypes": [
    {
      "name": "blog",
      "previewPath": "'blog'",
      "pageBundle": false,
      "clearEmpty": true,
      "fields": [
        ...
      ]
    }
  ]
}

[pauko]

Hello @estruyf !

Thanks for this hint! It seems to go into the right direction, however, when I tried it out I came across another remarkable behaviour.

But first I'll paste the relevant snippets of my frontmatter.json:

{ ...
"frontMatter.taxonomy.contentTypes": [ ...
      {
      "name": "strategic-decision",
      "pageBundle": false,
      "template": "[[workspace]]/templates/strategic-decision.md",
      "filePrefix": null,
      "clearEmpty": true,
      "fields": [ ...
        {
          "title": "Draft",
          "name": "draft",
          "type": "draft",
          "description": "Is this document in draft state?",
          "required": true,
          "default": true
        },
        {
          "title": "State",
          "name": "state",
          "type": "choice",
          "description": "lifecycle state of decision record",
          "required": true,
          "choices": ["proposed", "accepted", "rejected", "deprecated", "superseded"],
          "default": "proposed",
          "when": {
            "fieldRef": "draft",
            "operator": "eq",
            "value": false
          },
        {
          "title": "superseded by",
          "name": "superseded_by",
          "type": "contentRelationship",
          "description": "list of references to strategic decisions that supersede that one",
          "contentTypeName": "strategic-decision",
          "contentTypeValue": "slug",
          "required": true,  // this is what we were initially talking about
          "multiple": true,
          "when": {
            "fieldRef": "state",
            "operator": "eq",
            "value": "superseded"
          }, ... ] }

Please note the cascade of draft => state => superseded_by by conditions.
When I set clearEmpty: true, the toggle switch of draft is fixed, I can't toggle it any more. Consequently, I can't test the cascade to the end, because state does not become visible so that I could change it to superseded, then superseded_by field is also never visible in the FrontMatter sidebar.

But as you hinted, initially the superseded_by field is removed, because of clearEmpty. I just can't test its reappearance thoroughly because of the behaviour of the cascaded fields.

[estruyf]

@pauko, the latest beta version has fixed the draft field issue.

I will validate the behavior with your configuration.

[estruyf]

So it is the following behavior that we need to get fixed:

Steps:

• You publish the page
• The state field its condition is met and shows up
• Change the state field its value to superseded
• The superseded_by field shows up
• Set the page as draft -> the state field disappears, but the superseded_by field is still shown

Questions

When you set the page as draft again, do you expect the state and superseded_by fields to be removed from the front matter?

[pauko]

Good question!
According to the way my developer team defines the workflow and life cycle of decision records, we don't plan to go back to draft: true once it has arrived at draft: false, so I have not thought about this situation yet.

Independent from this I'd want superseded_by to disappear as well, because I expect the cascade of conditions to be evaluated from the beginning of the cascade on each change of values.

[pauko]

Relates to #707
Implemented in #709
Implemented in #710