building KF5 projects against a different Qt5 version (than the one the KF5 frameworks were built against)

[David Faure]

On Sunday, April 26, 2020 5:50:40 PM CEST René J.V. Bertin wrote:
> On Sunday April 26 2020 16:58:10 David Faure wrote:
> >> As a side-note, I'd even argue that
> >> it would make sense to provide an all-inclusive header per framework,
> >> just
> >> like Apple's frameworks do.
> >
> >It's said to improve compilation times with precompiled headers, but in
> >practice nobody knows if the person compiling the code has that, so I fail
> >to see the point.
> 
> The possibility to use precompiled headers is only an argument here when
> increased compilation times are brought up as an argument against such a
> header. But that's not really an argument if you can continue to use just
> the headers you need. 

Well, then you never need all-inclusive headers.

> >Who needs all of <KCoreAddons>? Nobody.
> 
> I could just as well maintain that nobody needs any of that particular
> framework ;) 

OK now you make no sense at all anymore, since I can give you 500 proofs of 
the contrary: actual pieces of code that use some parts of KCoreAddons, and 
none of them which use all of it.

> But the question isn't who needs all of. People including
> <AppKit/AppKit.h> or (better example) <Accelerate/Accelerate.h> also rarely
> need all of those frameworks. It's just a convenience: no need to jump back
> and forth between your editing location and the file preamble (after
> deciding if you want the required additional header in the implementation
> file or in the corresponding header file), and no need to maintain a long
> list of include statements which ideally you should prune every time you
> stop using a certain class. (Just how often do people forget to remove the
> corresponding header?)

And then people commit code that uses "everything", slowing down compilation 
times. We don't accept it in KF5 code (nor in most of KDE apps/workspace 
AFAIK), I don't see why we should provide something that we forbid.

> I still call me seeing the warning a pure chance given the fact it's there.
> The fact of me seeing it if it were not there would also be a pure chance
> ... hopefully close enough to 0 ;)

-Werror=undef is your friend.

Actually I'll add it to my default set of flags, to see how much breaks ;-)

-- 
David Faure, faure at kde.org, http://www.davidfaure.fr
Working on KDE Frameworks 5