[Development] Branch for adding Q_DECL_OVERRIDEs

[Thiago Macieira]

On quinta-feira, 27 de outubro de 2016 16:43:59 PDT Александр Волков wrote:
> Hi all,
> 
> Many methods are still missing 'override' specifier.
> You can find them by compiling with gcc's -Wsuggest-override.
> It improves code readability and helps to find unused code
> (e.g. https://codereview.qt-project.org/#/c/174370/ )
> Are there plans about adding 'override' or 'Q_DECL_OVERRIDE'
> and which branch is preferred for such changes?

I would prefer we did not add Q_DECL_OVERRIDE at all to current code. We may 
add "override" if that keyword is allowed by all compilers, otherwise leave it 
as it is.

GCC and Clang support a warning for "inconsistent override", which is caused 
by having some overridden methods marked but not others. So the recommendation 
is:

1) for new classes, always mark with Q_DECL_OVERRIDE

2) for existing classes, if possible use Q_DECL_OVERRIDE, but be careful to be 
consistent (be careful with #ifdef'ed functions too!). It's ok to add a 
handful of other Q_DECL_OVERRIDE to other functions in the same class, but 
don't do it if it uglifies your patch. Instead, leave it out.

3) if you get an inconsistent override use warning, fix it

Note that only #3 applies to the 5.6 branch. You can't add new public classes 
or public methods in 5.6 or 5.7. And you should not be adding even new, 
private, polymorphic classes in those branch. And there's only a short window 
while that is permitted in 5.8 too.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center