[rb-general] lzip/plzip alternatives

[Daniel Shahaf]

Vagrant Cascadian wrote on Wed, Apr 19, 2017 at 13:58:38 -0700:
> On 2017-04-19, Sylvain wrote:
> > On Wed, Apr 19, 2017 at 06:53:24PM +0000, Peter Stuge wrote:
> >> On Tue, Apr 18, 2017 at 08:43:05PM +0000, Daniel Shahaf wrote:
> >> > Sylvain wrote on Tue, Apr 18, 2017 at 21:50:23 +0200:
> 
> >> > It's perfectly fine for lzip and plzip not to produce identical output
> >> > to each other; whichever of them was *actually used* by the build should
> >> > be recorded in the .buildinfo file, which would enable reproducing that
> >> > particular build.  (That's exactly analogous to a "gzip 1.3 and gzip 1.4
> >> > produce different outputs for identical inputs" situation.)
> >
> > .buildinfo is nice but this is specific to Debian packaging AFAICS.
> 
> That's certainly not the intention; there is some work done already to
> support RPM based systems as well.

That notwithstanding, not all distros / packaging systems have the same
features.  (For example, FreeBSD doesn't have alternatives, and Debian
doesn't have USE flags.)  Therefore, the buildinfo format is going to
have to have per-distro or per-package-format extensions.  A Debian
extension can record alternatives, a FreeBSD extension can record the
contents of /etc/make.conf, and so forth.

This isn't as bad as it sounds, since, as Vagrant explains, reproducing
a binary built on distro Y is generally only going to be possible on
that Y.  (So having Y-specific fields introduces no new requirements on
attempts to reproduce)

> All a .buildinfo file is is a codified assertion "I built software X
> with build environment Y, and got result Z."

Cheers,

Daniel