Re: awk: essential virtual package?

[Santiago Vila <sanvila@unex.es>]

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On 18 Feb 1998, James Troup wrote:

> Santiago Vila <sanvila@unex.es> writes:
> 
> [ ... ]
> 
> > Perhaps we should just make mawk and gawk to Pre-Depend on libc6
> > instead?
> 
> With all due respect, you've 100% missed the point of making awk an
> essential package, the idea is to ensure that there is always an awk
> available for {{pre,post}{inst,rm} scripts etc. without the need for a
> dependency.  If we go out of our way for perl in the same regard, to
> not to do it also for good old awk would be criminal.

No, I have not missed the point. Simply, you didn't understand the
meaning of "instead". Please read.

Manoj said that base-files should Depend on awk, so that awk is
both "essential" and "virtual". I think everybody agrees on this. [ I will
add the Depends line again in the next base-files release ].

However, Manoj suggested that base-files should not only Depend on awk
but *Pre-Depend* on awk.

But since you can not both *remove* one awk and *install* another awk on
the same dpkg run, I think that the Pre-Depends line is not needed at all
in base-files (i.e. "Depends: awk" is enough to ensure that awk is
*installed* on the system).

However, to ensure that awk is always present and *it always works*
(i.e. it may be used safely in {pre,post}{inst,rm} scripts)
perhaps mawk and gawk should Pre-Depend on libc6 (this is in addition to
having base-files to *Depend* on awk), since any of them may be awk, which
is essential. [*]

So *instead* of having base-files to Pre-Depend on awk, perhaps we should
make mawk and gawk to Pre-Depend on libc6 (and base-files Depend on awk).
If you read again my mail, I said "I'm not sure that base-files should
Pre-Depend on awk [...]". I did *not* say "instead of making base-files
to Depend on awk".

[*] Example: mawk.deb, B.deb and libc6.deb are hamm packages, which we
are going to install in a bo system. We issue the following command:

dpkg -i mawk.deb B.deb libc6.deb

If awk is currently mawk and B's preinst uses awk, it will fail.
A similar example could be made for gawk. Since any of them may be awk,
the only workaround for this is to make both mawk and gawk Pre-Depend on
libc6.

Is this clear now?

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