qmlscene crashes if music app is started while mediascanner is extracting

[Michi Henning]

I'm attaching an archive with about 7000 "songs" (each of which is a second of silence).

To reproduce the problem, make sure that the music app isn't running and unpack the archive somewhere under the Music directory. This causes mediascanner to start indexing the files. (It'll take about 10 minutes on Mako.)

While mediascanner is still indexing, start the music app. A few seconds later, qmlscene crashes. (I'm seeing this with image 326 from rc-proposed.)

I'm also attaching the crash file.

[Michi Henning (michihenning)]

I've managed to start the music app without a crash. But it takes well over 60 seconds (!) before the spinner goes away and the song list appears.

Following the application log, it looks like qmlscene is being asked to deal with the entire collection of 7000 songs up front. This is totally non-scalable.