1406159 - Intermittent double page header on https://upc.ch

Status: RESOLVED INCOMPLETE

(Core :: Networking, defect, P3)

Description

[Mike Taylor [:miketaylr]]

Attachment: double-header.png

Originally reported at https://github.com/webcompat/web-bugs/issues/11385

STR:

1. visit https://upc.ch

expected:

See a single "Welcome, make your selection" header

actual:

Sometimes, you get two. It seems to depend on a number of things, possibly location or locale. It reproduces for me and the reporter of the webcompat.com bug, but not for anyone else on my team. :/

regression range:

https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=10d42af6319d08daca29d5d163f301696b5ff1fd&tochange=b37a0bd71bbb1f3e5b4f58f1936d9cc0a38851d2

[Tracking Requested - why for this release]:

I'm not sure how widespread this might be... but requesting tracking just in case.

Comment 1

[Honza Bambas (:mayhemer)]

100% repro for me locally (fortunately).  

I turned tailing off with network.http.tailing.enabled;false (nearly completely reverting bug 1358060) and I can reproduce as well.  I confirmed that a build from a changeset just above one before bug 1358060 can't reproduce at all.

Hence, one of the changes not under control of that preference must affect this somehow.

Comment 2

[Honza Bambas (:mayhemer)]

(In reply to Honza Bambas (:mayhemer) from comment #1)
> 100% repro for me locally (fortunately).  
> 
> I turned tailing off with network.http.tailing.enabled;false (nearly
> completely reverting bug 1358060) and I can reproduce as well.

Only when I don't open a new tab (do a (hard)reload in the same tab.)

>  I confirmed
> that a build from a changeset just above one before bug 1358060 can't
> reproduce at all.
> 
> Hence, one of the changes not under control of that preference must affect
> this somehow.

Comment 3

[Jason Duell]

We could use a contact at UPC to debug this.  I contacted them and we'll see if we can get one of their web-devs to work with us.  (If you're a UPC web-dev and you're reading this, please create a Bugzilla account and post a comment in this bug, and we'll work with you).

Comment 4

[Honza Bambas (:mayhemer)]

So, I was again once able to reproduce this with trackers tailing disabled.  I start to think this is a site bug that we just expose, but I'm not 100% sure yet.

The page (when the problem happens) is doing a request for [1] twice, the source script call is [2].  When the bug doesn't reproduce, this request is made only once.  I don't see any immediate influence that tailing would have.

When I add a breakpoint at [2], the callstack is quite long and generic.  Looks like the header is added more than once to the element with ".nbx-content" class.  The same element has also ".promotion-snippet" class (internally referred as LGI.NBX.SNIPPET_SELECTOR), for whose children a load is made later (being performed at [2]) that causes to show the header twice.

The js code on the site is pretty complex and I'm not sure I will be able to figure this out that easily.


[1] https://www.upc.ch/content/www-upc-cablecom-ch/en/teasers/default/jcr:content/promofullwidth1.html?wcmmode=disabled
[2] https://www.upc.ch/etc/designs/upc-cablecom-ch/common/js/head.min.89cd65d771ff7da03c3bc4cde91f4f37.js:5303:2

Comment 5

[Honza Bambas (:mayhemer)]

The web page has changed (specifically now before Christmas) that it's hard to verify if the bug is still valid.  Closing for now as incomplete.