gdprEnforcement and prebid-server: User sync not allowed for null

[rsnigel]

Type of issue

When using prebid-server together with gdprEnforcement, each server side bidder causes a warning that user sync is not allowed for null. Not checked in detail, but it looks like it completely breaks the user sync for server side bidders.

Message:
utils.js:257 Prebid WARNING: User sync not allowed for null

Description

Setup:

• 4 client side bidders
• 4 server side bidders
• prebid compiled with consentManagement, gdprEnforcement, and prebidServerBidAdapter modules (and others for bidders)
• prebid.js 4.26.0

User sync for the client side bidders is working as expected.

Client side bidding

When looking at src/adapters/bidderFactory.js:201, the responses and consent information is passed to registerSyncs. This is used within the function to pass it to the gdprEnforcement module and it works as expected.

Server side bidding

In modules/prebidServerBidAdapter/index.js:288, registerSyncs called with empty parameters. This is passed to the gdprEnforement module which is causing in modules/gdprEnforcement.js:219 to return null for the config.getCurrentBidder() and further more failing the validation and rejecting purpose1Rule, therefore rejecting the user sync.

Steps to reproduce

When running this setup, you only need to have server side bidders enabled and the gdprEnforcement module will issue the warning "utils.js:257 Prebid WARNING: User sync not allowed for null" in gdprEnforcement:225.

Expected results

Server side bidding should be working with gdprEnforcement and no warning should be issued.

Actual results

Server side bidding user sync is not working due to bug in gdprEnforcement/ServerBidAdapter.

[bretg]

I agree there's a spurious warning here, but it's unclear to me that user syncs are broken. I set up a local test page and see the server-side sync happening.

1. We still want to be able to do client-side user-syncs for server-side bidders because there are DSP syncs that can take place and without doing some client-side syncing, there may be a cold-start problem. (Related tangentially to Improve client-side footprint for server-side adapters #6361)
2. As for the warning, set a breakpoint at line 16699 of sneezy.aws.rubiconproject.com/rp-eng-soln/prebid/prebid-431-multibid-debug.js
3. I don't understand the code in generateTrap() -- it seems to be walking off the end of an array on purpose.

Here's a test page. Git wouldn't let me attach an HTML file, so rename this with the html extension.
prebid_server_test_1001-gdpr.txt

[ChrisHuie]

@rsnigel we believe this is a warning but not an actual blocking of user sync? Is this what you are experiencing? If not could you please provide a test page.

[dgirardi]

@rsnigel I cannot reproduce using prebid master. Is this still an issue? I tested with the page @bretg provided and I do see the warnings there (using prebid v4.31.0-pre), but they go away after updating.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[patmmccann]

Closing for lack of activity; it appears to be solved by upgrading prebid. Let us know if we should re-open.