#2503 7-zip fails to build on Gentoo due to provided source archive being non-standard

[David McInnis]

Gentoo relies on the app-arch/xz-utils package package to provide the xz program for unzipping 7z2408-linux-x64.tar.xz source archive. If this package is not compiled with the "+extra-filters" use flags 7zip will fail to build with the following error:

>>> Unpacking 7z2408-linux-x64.tar.xz to /var/tmp/portage/app-arch/7zip-24.08/work
xz: /var/tmp/portage/app-arch/7zip-24.08/distdir/7z2408-linux-x64.tar.xz: Unsupported options
tar: This does not look like a tar archive

I reported this issue as [bug 937989]((https://bugs.gentoo.org/show_bug.cgi?id=937989) to the app-arch/7-zip package in Gentoo indicating this failure.

This failure is due to the 7zip .xz archive being formatted in a non-standard way.

[Igor Pavlov]

I suppose it's Gentoo problem, because extra-filters (BCJ filter and another filters) are part of xz specification, and such filters must be supported by default xz decoder.
Only if we want smallest xz decoder for some embedded devices, we could remove extra-filters from decoder, if we are sure that we have no xz archives that use extra filters in that device.
But by default, xz decoder must support all filters from xz specification.

[Igor Pavlov]

Also note that 7z2408-linux-x64.tar.xz is not source code archive. It's binary for amd64 (x64) cpu.

[Michael Gilbert]

I've adjusted the dependency in Gentoo, feel free to close this.

[David McInnis]

Thank you for your corrections Igor. Gentoo decided it is indeed our problem and added the app-arch/xz-utils/xz-utils:extra-filters feature flag dependency to the app-arch/7zip package.

Please close this bug when you get a chance.

-Dave