[Development] Behavior changes in Qt

[Sorvig Morten]

On Oct 11, 2012, at 4:06 PM, BRM <bm_witness at yahoo.com> wrote:
>> 
> 
> How about opt-in (via configure or extra flags) until the next major release?
> I don't think doing the opt-in/opt-out/mandatory over several minor release would bode well for compatibility between minor releases, which is a big must.
> 
> For example, I have some software that is still running on Qt 4.5.1 in production; and component is running on Qt 4.7.4. Yet I need the behaviors in the overlapping code to be the same; without having to worry about getting the compilations right in both cases.

If I understand correctly you are compiling a shared code base against both Qt 4.5.1 and Qt 4.7.4?  I agree that use case would be harder if there were significant changes between 4.5 and 4.7. There are still changes between them today though, in the sense that each bugfix usually comes with a change in behaviour.

One solution is workarounds based on the Qt version. We are running Qt Creator against both Qt 4 and 5 using QT_VERSION #ifdefs for example.

Morten