"all" or "any" as Dependency Qualifiers

[Jonathan Yu <jonathan.i.yu@gmail.com>]

Hi:

This is a stupid idea, and I don't know any case where it might make
sense to do it, but it has occurred to me that Policy doesn't mention
anything explicitly forbidding it, as far as I can tell.

Lintian allows it through without warning about it. Presumably this is
because nobody has ever done something like this before.

In the current Policy (a cursory glance at Chapter 7), it's unclear
whether it is possible to do something like:
Depends: some-library [!all]

or:

Depends: some-library [all]

The latter would, of course, be equivalent to:

Depends: some-library

I wouldn't know if something similar applies to the third special
architecture keyword, 'source'.

I guess the reason why there are no warnings is because, according to
Debian Policy:

"If the current Debian host architecture is not in this list and there
are no exclamation marks in the list, or it is in the list with a
prepended exclamation mark, the package name and the associated
version specification are ignored completely for the purposes of
defining the relationships."

That means you've got some wiggle room in case we implement new
architectures -- dpkg will silently gloss over them if they don't
match the current architecture, as it understands "that
package/dependency isn't for me" -- a very wise idea indeed.

I'm just not sure about the expected behaviour when the "special"
keywords (all, any, source) are used.

Cheers,

Jonathan