[Development] API/ABI changes report

[Knoll Lars]

On 12/02/16 08:50, "Development on behalf of Sune Vuorela" <development-bounces at qt-project.org on behalf of nospam at vuorela.dk> wrote:

>On 2016-02-11, Thiago Macieira <thiago.macieira at intel.com> wrote:
>>> There are several remaining issues in the report. So I have some questions:
>>> 
>>> - Is class QPlatformScreen private and all related changes should be removed
>>> from the report?
>>> (http://abi-laboratory.pro/tracker/compat_report/qt/5.5.1/5.6.0-beta/8f965/
>>> abi_compat_report.html) 
>>
>> Yes, that's a private class (QPlatform* is QPA, like QWindowSystem*).
>
>It is a public private class. I'm not sure it is fully correct to hide
>it. I'm also not sure it is fully correct to keep it.
>
>Many parts of the QPA bits are unfortunately widely used. We should
>really work towards making it public ...

There are very good reasons we’re not promising compatibility on these parts. So far we have been doing incompatible changes in these APIs with almost every minor version of Qt. Keeping BC here would have made our QPA implementation impossible (or at least a *lot* harder) to maintain by now. 

These APIs should really only be used by a very limited set of plugins to Qt, not by general apps.If there’s something apps in general require, let’s discuss how a public API for that feature could look like. But we should not go down the road of starting to promise BC for our backend APIs.

Cheers,
Lars