[Development] [Qt5-feedback] 3rdpart platform plugins, tests and CI

[Rohan McGovern]

Holger Hans Peter Freyther said:
> 
> >> how difficult will it be to only checkout/update/build qtbase and not _all_ of
> >> Qt? Is this something that is planned?
> > 
> > That is already the way it works - as Shane Kearns pointed out in a
> > followup mail.  For testing qtbase, you get qt5, qtbase and v8.
> > For testing another gitmodule, you get just that gitmodule, plus the
> > gitmodules it depends on, plus qt5.
> 
> Sorry to be stubborn here. We try to have modules in Qt (in contrast to the
> monolithic qt as of the past), e.g. I could provide a 'Qt Monkey WebPage
> Scraper' module that is based on WebKit. Why would I want to build QtWebKit
> whenever I change something in my module? Do I miss the point?

No apologies necessary :)

If your module depends on QtWebKit, then you need some compiled QtWebKit
on your system.  Since nobody provides any recent Qt5 binaries at the
moment, the simplest way for you (and for our CI) to get that is to compile
it.

Reusing binaries from earlier builds would be great, but it makes the
test scripts more complex.  Currently I see it as an optimization, lower
priority than a lot of other pending work.  As mentioned on IRC, sure
we would accept patches into the test scripts which enable this way of
working.

> 
> So my question is. What prevents us from doing this:
> 
> Track QtBase        -> build QtBase (as unpacked by the CI system)
> Track QtWebKit      -> build QtWebKit (as unpacked by the CI system)
> Track QtDeclarative -> build QtDeclarative (as unpacked by the CI system)
> 

Just as described above - if you build qtdeclarative, you need the
things which qtdeclarative depends on, and the most pragmatic way to get
those at the moment is to build them yourself.

> (no qt5 submodule involved, just plain git repository)
> 

Avoiding the usage of qt5.git requires a bit more work; qt.pro in that
repository is currently treated as the canonical source of information used
to determine the order in which modules need to be built.  Implementing
another way to build the dependency tree (which I don't believe would be
particularly difficult) would remove the need to use qt5.git.