Re: cmp/diff

[Bruno Haible]

Hi Simon,

> Essentialy it boils down to:
> 
> ../../gltests/test-binary-io.sh: line 8: cmp: command not found
> test-init.sh: failed test: err not empty: ../../gltests/init.sh: line 648: 
> cmp: command not found
> ../../gltests/test-perror.sh: line 14: diff: command not found

'cmp' and 'diff' are among the programs that a 'configure' script and a Makefile
can assume to be present, see the GNU Coding Standards
<https://www.gnu.org/prep/standards/html_node/Utilities-in-Makefiles.html>.

> What do you think about rewriting these self-tests to avoid cmp/diff?

There is no adequate replacement. It would be possible to use 'md5sum'
instead of 'cmp'; but since 'md5sum' is not in the above list from the
GNU Coding Standards, this is not a useful direction.

Gnulib makes sure to pave over differences between different 'diff'
implementations; this was already a major headache. See tests/init.sh lines
589..669.

> https://gitlab.com/libidn/libidn/-/jobs/932649011

The Gitlab jobs typically start by installing packages into the build
environment. Yours has

  $ pacman -Sy --noconfirm make gcc

I guess that adding 'diffutils' to this package list will solve the problem.

> I read the DEPENDENCIES file a bit more careful after noticing that it
> has several mandatory dependencies that I find questionable, and I
> noticed this in the beginning:
> 
>   The following packages are needed by maintainers for using
>   'gnulib-tool'.
> 
> It doesn't say the packages are required for users building gnulib-based
> packages.  I can live with having diffutils installed as a maintainer.
> Was this subtle distinction intentional?

Yes, of course, we make a distinction between the packages needed for
creating the tarballs and the packages needed to build+install the tarballs.
The GNU Coding Standards matters for the latter.

Bruno