Re: virtual/alternative B-D (was Re: libtiff5 transition)
On 06/12/13 10:56, Colin Watson wrote:
> On Fri, Dec 06, 2013 at 10:19:14AM +0100, Thorsten Glaser wrote:
>> On Thu, 5 Dec 2013, Jay Berkenbilt wrote:
>>> * If your package build-depends on libtiff5-dev, you don't HAVE to do
>>> anything, but you may be helping yourself in the future if you change
>>> the build dependency to libtiff-dev (>> 4.0.3-6~).
>
> This won't work as libtiff-dev is virtual.
Does this imply that libtiff-dev should be a non-virtual, empty
dummy/dependency package, built by, and depending on, the currently
favoured version of tiff? If a virtual package can't have multiple
implementors, then it looks remarkably similar to a non-virtual package.
(Or libtiff-dev could be non-empty, and libtiff5-dev empty or virtual.)
As far as I can see, changing from (libtiffN-dev Provides libtiff-dev,
libtiff(N+1)-dev does not) to the other way round has an inherent race
condition: either there'll be a brief window in which the archive
contains two providers of libtiff-dev (non-deterministic builds), or a
brief window in which the archive contains no provider of libtiff-dev
(FTBFS for everything depending on libtiff-dev). Perhaps this doesn't
matter in practice because that time is short, I don't know.
S
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