When startProgress, endProgress, and progress were all 0 (as provoked
by tst_QPropertyAnimation::startWithoutStartValue()), we'd calculate
0/0 and ubsan complained:
qvariantanimation.cpp:284:60: runtime error: division by zero
Fix by detecting progress - startProgress == 0 and setting
localProgress = 0.0 in that case. This is a logical result, even
though it might not be what IEEE754 rules would have yielded.
A more comprehensive change that aims to reliably keep localProgress
∈ [0,1] and thus avoid the infinities when endProgress ==
startProgress, is outside the scope of this patch, which deals only
with the UBSan error.
Pick-to: 6.3 6.2 5.15
Change-Id: I5258b054a2060006795f49fb1cd7604aea3ed46b
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>
52da10f645