Re: [gentoo-dev] [pre-GLEP] Gentoo binary package container format

[Roy Bamford <neddyseagoon@gentoo.org>]

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On 2018.11.18 09:38, Michał Górny wrote:
> On Sun, 2018-11-18 at 10:16 +0100, Fabian Groffen wrote:
> > On 17-11-2018 12:21:40 +0100, Michał Górny wrote:
> > > Problems with the current binary package format

[snip]

> > > 2. **The format relies on obscure compressor feature of ignoring
> > >    trailing garbage**.  While this behavior is traditionally
> implemented
> > >    by many compressors, the original reasons for it have become
> long
> > >    irrelevant and it is not surprising that new compressors do not
> > >    support it.  In particular, Portage already hit this problem
> twice:
> > >    once when users replaced bzip2 with parallel-capable pbzip2
> > >    implementation [#PBZIP2]_, and the second time when support for
> zstd
> > >    compressor was added [#ZSTD]_.
> > 
> > I think this is actually the result of a rather opportunistic
> > implementation.  The fault is that we chose to use an extension that
> > suggests the file is a regular compressed tarball.
> > When one detects that a file is xpak padded, it is trivial to feed
> the
> > decompressor just the relevant part of the datastream.  The format
> > itself isn't bad, and doesn't rely on obscure behaviour.
> 
> Except if you don't have the proper tools installed.  In which case
> the 'opportunistic' behavior made it possible to extract the contents
> without special tools... except when it actually happens not to work
> anymore.  Roy's reply indicates that there is actually interest in
> this
> design feature.
> 
[snip]

Team,

I use to post something like https://wiki.gentoo.org/wiki/Fix_My_Gentoo
with a link to Patricks binhost on the forums every three or four months. 
It made it worth writing that wiki page anyway.

We still get users removing elements of their toolchain or glbc from time
to time.  The requirement that I didn't express very well, is that it shall 
be possible to install binary packages without the use of any Gentoo
specific tooling.

The current tarball of tarballs proposal would satisfy that requirement.

Its unlikely that a custom binary format would.  Of course, this being 
Gentoo someone would write a run anywhere script that did the 
unpicking, We already have deb2targz and rpm2targz. We have the 
opportunity to design out binpgk2targz before it exists.

-- 
Regards,

Roy Bamford
(Neddyseagoon) a member of
elections
gentoo-ops
forum-mods

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