So I guess this is at least partially broken again:
http://tickets.musicbrainz.org/browse/MBS-7053

Unlike above examples, there are no fingerprints.

@HumHumXX: That recording has PUIDs, so it won't be deleted.

Different example: http://musicbrainz.org/recording/b9ab95d0-1237-4787-8f9c-cca64aba389e

No "Add track" or "Add standalone recording" edit. The track on that Ministry of Sound release was (erroneously, I think) linked to http://musicbrainz.org/recording/780e9c96-97cf-4c32-a280-a11eb43382b8 in http://musicbrainz.org/edit/14479729. (Btw, shouldn't this edit be listed in the recording history?)

Looking at the edits in the database and comparing them with an edit I know was for a non-album track, there isn't enough information there to know whether or not those tracks were originally non-album tracks or not, so I don't think we can do anything about those.

Two examples of orphaned recordings ("tracks", back in the day) that were added not as standalone recordings but to releases that have been removed in the meantime:

http://musicbrainz.org/recording/3540562f-ce15-476c-b8c4-331a51d30a4b/edits
http://musicbrainz.org/recording/6df4632b-070b-4f6f-9e8a-227a01faadd3/edits

The cleanup script has run (and deleted 19379 recordings), and the triggers to automatically do this have been added. As far as I'm aware, this fixes the issue. If you still find recordings that you don't think should exist, please reopen this ticket.

Assigning to me, I'll begin looking at this tomorrow morning.

Let me reiterate that this bug, combined with MBS-5126, is severely affecting the quality of the data that we provide to our customers (if we want to put it that way).

Upping this to major because this bug necessitates lots of recordings cleanup not only after remove release edits, but also (almost every time) when a release add was canceled or voted down.

http://musicbrainz.org/edit/18809544

"Add release" failed, recordings (and artists) were not removed. The artists are not removed because a recording exists.

Lots of artists like:
http://musicbrainz.org/artist/c2373d72-00d5-45c6-b4f6-df6af4ee000b
http://musicbrainz.org/artist/4b8a62f1-9d9f-4111-a0e3-73493926d4a1
http://musicbrainz.org/artist/1611cb56-0720-43c1-8874-b3c32eeee88f
http://musicbrainz.org/artist/29f105b8-4716-49f2-8565-47005fcf6fb6
http://musicbrainz.org/artist/914014dd-4086-46e7-9e70-b50439c02655
http://musicbrainz.org/artist/e82194d7-674e-49a1-8970-bbb3b1f85ead
http://musicbrainz.org/artist/694dc250-a7f7-4573-8805-0e4876741743
...

Oh right, I didn't consider that case, but since the first edit of "normal" recordings is Add release it seems doable.

The trivial way is that those recording have an explicit 'add recording' edit in their edit history.

I just thought of a warning on this ticket.
If a new release that is using pre-existing Stand Alone Recordings (SAR) / Non Album Tracks (NAT), those shouldn't get wiped if the release is voted down or deleted...
I don't see trivial way of knowing if we are in this case though...

Disc 1 was added in http://musicbrainz.org/edit/12694844 so now I can at least remove the recordings.