setReferrerUrl is ignored #17047

When using the JS tracking setReferrerUrl seems to be ignored.

ENV

Matomo 3.14.0

CODE

    var _paq = _paq || [];
    _paq.push(['trackPageView']);
    _paq.push(['enableLinkTracking']);
    if (document.referrer && document.referrer.search(/bad/ > -1) {
      console.log('Unsetting referrer, current:'+document.referrer);
      _paq.push(['setReferrerUrl','']);
    }

    (function() {
    var u='//' + piwik_url + '/';
    _paq.push(['setTrackerUrl', u+'piwik.php']);
    _paq.push(['setSiteId', siteid]);
    var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
    g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
    })();
    }

EXECUTION

We see that code which sets referrer is run

console.log

Unsetting referrer, current:...

nevertheless the current referrer as seen by

document.referrer
https://bad.domain/

is also set in piwik.php?....&urlref parameter

urlref: https://bad.domain/

A guess from some inspection that I did in the tracking js might be that setReferrerUrl might have to be executed before trackPageView

In this code that is run (breakpoint in the debugger)

            function logPageView(customTitle, customData, callback) {
                configIdPageView = generateUniqueId();

                var request = getRequest('action_name=' + encodeWrapper(titleFixup(customTitle || configTitle)), customData, 'log');

                sendRequest(request, configTrackerPause, callback);
            }

and inside getRequest the configReferrerUrl is the detected from document.referrer and not the set one.

Also this code

             */
            this.setReferrerUrl = function (url) {
                configReferrerUrl = url;
            };

runs (breakpoint) after the above.

Maybe this has to do with the method applied first as noted in applyFirst=... .
setReferrerUrl is not in this list.

@basos9 your inspection looks correct. You'll need to call this method before the page view. I suggest you reorder the tracking code to

    _paq.push(['enableLinkTracking']);
    if (document.referrer && document.referrer.search(/bad/ > -1) {
      console.log('Unsetting referrer, current:'+document.referrer);
      _paq.push(['setReferrerUrl','']);
    }
    _paq.push(['trackPageView']);

We wouldn't want to add this to applyFirst unfortunately as someone might initially want to track the page view with the original referrer URL first.

I'll mention this in the docs though.