Re: dash: fails to install when /usr/share/man doesn't exist

[Jonathan Nieder <jrnieder@gmail.com>]

Neil Williams wrote:

> /usr/share/man/ is not essential in it's own right. Packages should
> still install correctly if /usr/share/man does not already exist. The
> problem reveals itself because dpkg-divert correctly skips files which
> don't exist but then dash assumes that the file does exist.
>
> with dpkg-filters, it is quite possible that ./usr/share/man will not
> exist on an otherwise standard Debian system.

Thanks for explaining.  This being preinst, I suppose the simplest
fix would be to run

	mkdir -p /usr/share/man/man1

before writing a symlink there.  (base-files contains /bin and
/usr/share/man but not /usr/share/man/man1.)

> ./usr/share/doc

Hmm, whenever a directory under doc/ changes to a symlink or vice
versa, there will be trouble (based on "grep -F /usr/share/doc
/var/lib/dpkg/info/*inst").  I agree that stripping away docs to save
space is a worthwhile use case; sounds worth documenting in policy.

> However, simply having empty directories isn't going to prevent ln
> failing if the original file does not exist either.

In this case it would.  It is intended that the targets of the
symlinks may not exist yet, since if I run

	rm -f /usr/share/man/man1/dash.1.gz
	apt-get reinstall dash

then the second command must not fail.

> e.g. with multistrap, it is trivial to write a setupscript which
> ensures that particular directories, like /usr/share/man/ exist before
> packages get configured.

Ah, good to hear.

Thanks again for the clear explanation, and thanks for making some
nice tools.

Regards,
Jonathan