[Pkg-hhvm-team] Bug#809873: Bug#809873: Bug#809873: hhvm: FTBFS with libpng16

[Tobias Frost]

Am Donnerstag, den 07.01.2016, 11:45 -0800 schrieb Faidon Liambotis:
> On Thu, Jan 07, 2016 at 07:29:02PM +0100, Tobias Frost wrote:
> > Am Donnerstag, den 07.01.2016, 08:55 -0800 schrieb Faidon
> > Liambotis:
> > > On Thu, Jan 07, 2016 at 09:06:58AM +0100, Tobias Frost wrote:
> > > We /could/ however switch our B-D to libpng12-dev | libpng-dev
> > 
> > PS: Don't do that. This would jeopadize the planned binNMU -- the
> > buildds will take libpng12-dev for the rebuild, and that package
> > will
> > only be gone after libpng12 is removed from sid, that is when the
> > transition is completed. 
> > With only libpng-dev, no additional sourceful upload will be
> > reuquired.
> 
> With only libpng-dev as you say, the build daemons would not know
> which
> of the two versions to pick when both would be available, no?

This will not happen, as this is coordinated. We will make sure that
there is one alternative available. 

> I recall that even lintian warns about this
> (virtual-package-depends-without-real-package-depends) and suggests
> to
> never depend on a virtual package without a real package as an
> alternative first.

We have many packages only depending on libpng-dev, without lintian
emitting any warning. 

Also, the buildds will always ONLY install the first alternative, they
ignore the others. 

The rule is meant for virtual packages out of this list [1], not the
"private" ones:
[1] https://www.debian.org/doc/packaging-manuals/virtual-package-names-
list.txt

> At minimum, we'd have to depend on libpng16-dev | libpng-dev, AIUI,
> right?

No, please not. 
First, that will cause trouble for the next transistion.
Also, (with the information above), this will not work until libpng16-
dev is in sid. 

> Faidon