When creating a private browsing session, SoupNetworkSession is reusing the default cookie jar. It should probably use a separate cookie jar, as seems to be the case for the CF layer (NetworkStorageSessionCFNet.cpp).
Created attachment 228818 [details] Patch
Created attachment 228821 [details] rebasing patch
I don't think webkitgtk+ supports private sessions atm. Not against adding support for it, but will either or both of EFL or GTK+ actually use it?
(In reply to comment #3) > I don't think webkitgtk+ supports private sessions atm. Not against adding support for it, but will either or both of EFL or GTK+ actually use it? I am not sure of EFL. There is a webkitgtk "enable-private-browsing" property in webkitgtk doc. It is marked as experimental. This property value seems to propagate up to soup sessions.
I took a look at SoupNetworkSession.cpp commit history. Initially, createTestingSession and createPrivateBrowsingSession were ResourceHandle methods. createTestingSession was reusing the default cookie jar. createPrivateBrowsingSession was creating a new cookie jar. When moving those methods in SoupNetworkSession, this was swapped between the two methods.
This is fixed in ephemeral mode.