Type of issue

Possible bug?

Description

When the following schain config is set, the intention is it is only sent to that bidder:

This is probably specific for Prebid Server integrations with prebid.js since it has multiple bidders in the call, so the ORTB Converter does not have the logic needed to filter out this schain from the top level since it is just checking if the bidder is in the call?

pbjs.setBidderConfig(
  {
    bidders: ['myBidder'],
    config: {
      schain: {
        validation: 'relaxed',
        config: {
          ver: '1.0',
          complete: 1,
          nodes: [
            {
              asi: 'prebid.com',
              sid: 1234567,
              hp: 1
            }
          ]
        }
      }
    }
  }
);

When the ORTB Converter does its logic to generate the Prebid Server request, it correctly seems to set this here:

ext.prebid.schains =

[
    {
        "bidders": [
            "myBidder"
        ],
        "schain": {
            "ver": "1.0",
            "complete": 1,
            "nodes": [
                {
                    "asi": "prebid.com",
                    "sid": 12345678,
                    "hp": 1
                }
            ]
        }
    }
]

But, it is also copied over to the request.source.ext.schain object like so:

        "schain": {
            "ver": "1.0",
            "complete": 1,
            "nodes": [
                {
                    "asi": "prebid.com",
                    "sid": 12345678,
                    "hp": 1
                }
            ]
        }

I am wondering if this is expected behavior, should the ORTB converter not set this here and just leave the bidder level one shown before?

Test page

https://jsfiddle.net/1zpfas58/1/

Call to PBS Screenshots:

ext.prebid.schains:

source.ext.schain:

Expected results

I am not too sure (I am not too keen on how schains should work!)

But I believe the top level source.ext.schain should NOT be there?

Actual results

Top level schain is sent