This is because we are passing true unconditionally as isHTTPFamilyRequest parameter of createSoupRequestAndMessageForHandle in continueAfterWillSendRequest. I wrote a unit tests using a data URI to reproduce it: $ bin/TestWebKitAPI/WebKit2Gtk/TestLoaderClient -p /webkit2/WebKitWebPage/redirect-to-data-uri /webkit2/WebKitWebPage/redirect-to-data-uri: (WebKitWebProcess:19126): GLib-GObject-WARNING **: invalid cast from 'SoupRequestData' to 'SoupRequestHTTP' (WebKitWebProcess:19126): libsoup-CRITICAL **: soup_request_http_get_message: assertion 'SOUP_IS_REQUEST_HTTP (http)' failed ** ERROR:../../Tools/TestWebKitAPI/gtk/WebKit2Gtk/WebViewTest.cpp:292:void resourceGetDataCallback(GObject*, GAsyncResult*, gpointer): assertion failed: (data) Abortado
Created attachment 251007 [details] Patch
Comment on attachment 251007 [details] Patch Nice catch!
Committed r182943: <http://trac.webkit.org/changeset/182943>