sync jumps outside of short, undetectable birate tracks

[Sébastien BLAISOT]

64 bits Mixxx 1.12 beta r5616 and r5620 under windows 7 64bits and windows 10 64bits

Step to reproduce:
1) add the attached track in your library
2) analyse track (so BPM = 0 because undetectable)
2) load it into deck1
3) start play
4) immediately hit the sync button of the playing deck

Actual result:
Play position jumps outside of track (sometimes spinnies become silly, turning over-speed), no more sound (silence)

Expected result:
no action taken, you can not sync if you don't know the BPM of the track (and also you don't have anything to sync with)

[Sébastien BLAISOT (sblaisot)]

Hitting sync (shortly) rewind before the track.

Long pressing sync has the same effect as fast-rewind all the time sync_enabled==true

[Sébastien BLAISOT (sblaisot)]

The amount of time being rewinded depend of how long you presse sync (staying in the "short-press" time).

so a fast click&release on the sync button rewinds something like 10 seconds.
a not-so-short press-then-release, but just a little less than a long-press, leads to a 30 seconds rewind.

[Sébastien BLAISOT (sblaisot)]

if relevant, seen on latenight skin.

[Owen Williams (ywwg)]

fixed

[Owen Williams (ywwg)]

https://github.com/mixxxdj/mixxx/commit/46f34640ffda8fed315692b783b30d950bc8a017

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8302