[Development] Basing Qt Creator Coding Style on C++ Core Guidelines?

[Lisandro Damián Nicanor Pérez Meyer]

On lunes, 21 de noviembre de 2016 17:07:08 ART Thiago Macieira wrote:
> On segunda-feira, 21 de novembro de 2016 21:33:58 PST Lisandro Damián
> Nicanor
> Pérez Meyer wrote:
> > > I remember in the MeeGo days when building MeeGo with OBS spent an hour
> > > on
> > > a very beefy machine compiling Qt, with most of the resources in the OBS
> > > farm unused because nothing else could be built yet. With Qt 5 and our
> > > split packages, this lessens because only qtbase is the bottleneck.
> > 
> > As long as qtbase's private headers do not change. I guess in that case
> > one
> > who knows exactly what would affect will just rebuild the necessary parts,
> > the rest of us need to get all the stuff rebuilt (17 submodules? maybe
> > they
> > are more right now).
> 
> My point is that there are packages that depend only on qtbase libraries, so
> they can start rebuilding as soon as qtbase is done, while the system is
> building qtsvg and qtserialport in another node in the farm. And this
> scenario was the "rebuild world" case, regardless of whether there were ABI
> breakages or not.
> 
> You're right that if you're rebuilding only what needs to be rebuilt, then
> an update to qtbase should trigger only rebuilding of packages that
> depended on the private API. With the ELF version marker, that should be
> easy to detect now.

Just for the record, every time that qtbase's private symbols change we end up 
requiring a rebuild of almost all the submodules. We might be able to do 
better with some more hacks, but as we normally require this when we are 
pushing a new upstream release there is currently not much of a point.

> That said, sometimes rebuilding even if there was no dependency on the
> private API could result in improvements. For example, every time we add
> overloads there's a chance that the new method is faster and will get
> selected.

Fair point.

[snip]
> And ELF symbol versioning. That allows both libraries to be loaded into
> memory and not interfere with each other, so long as you don't pass data
> from one to the other.

Indeed, that would really be great.

-- 
Simulations are not data. In God we trust, all the others must supply data.
 Walter Opyd, "Show Me The Data" IEEE Spectrum's reader's comments,
 http://www.spectrum.ieee.org/nov04/4004

Lisandro Damián Nicanor Pérez Meyer
http://perezmeyer.com.ar/
http://perezmeyer.blogspot.com/
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