[Development] Moving Qt's undo framework out of Qt Widgets

[Morten Sørvig]

> On 5 Apr 2017, at 12:37, Oswald Buddenhagen <oswald.buddenhagen at qt.io> wrote:
> 
> On Wed, Apr 05, 2017 at 09:24:15AM +0000, Mitch Curtis wrote:
>> So, should this get its own module, and if so, can widgets depend on
>> it?
>> 
> an own module just for that seems over the top - i don't think we want
> to end up with 100 micro-libraries.
> 
> however, splitting up qtcore has been raised multiple times, and
> putting this into one of the resulting libs would seem reasonable. for
> example, this seems conceptually quite related to item models. possibly
> also state machine. and animation. these are all things which initially
> elicit a "huh, this is core?" response, until you think a bit about it.
> GuiSupport may be a better name for it (i'm sure some will disagree).

So both QtCore and QtGui could be split up into “Core” and “Kitchen Sink”;

QtCoreCore    QtGuiCore
QtCoreSink    QtGuiSink

QtWidgets and QtDeclarative would depend on all of these; are we gaining
anything? Well:

1) The “Core” versions will be satisfyingly uncluttered.
2) Those who do not use QtWidgets or QtDeclarative can possibly depend
   on smaller libraries.

> 
> also, a plan for splitting up qtbase wouldn't be entirely off the mark.
> untangling tests and examples would be the major effort here.

(At the risk of derailing the discussion (sorry Mitch)) No, we should
follow Google and Facebook’s lead: large monolithic repos (as large as
the infrastructure can handle), which can be updated atomically.

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