Re: Comments on the "Changing the default system shell" talk
Raphael Hertzog <hertzog@debian.org> writes:
> Hi,
>
> I haven't jumped into this discussion it but it starts annoying me...
>
> On Sun, 26 Jul 2009, Goswin von Brederlow wrote:
>> The choice being that the admin may dpkg-divert /bin/sh to whatever
>> shell he wants and he then can fix whatever breaks. Great. We already
>> have exactly that now. There is nothing added. No mechanism and no
>> assurances that things won't break.
>
> Things might break when you update the link automatically during upgrades.
>
> By limiting the number of packages that could fiddle with the link, we do
> keep things robust. Officially supporting a wider choice for /bin/sh would
> be more likely to lead to breakages.
>
> I'm happy to leave it to admins to assume any other choice.
>
> You can certainly create an helper tool that helps you change the /bin/sh
> link while still keeping things working. The helper tool would create
> a package that pre-depends on the selected shell and does the required
> dpkg-divert commands (those created packages would provide "default-shell"
> and conflits against "default-shell" to ensure only one of them is
> installed).
>
> That doesn't need to be coupled to the current project of changing
> the /bin/sh symlink. So stop bringing this up and create that helper tool
> if that's what you're looking for.
>
>> You say that the default /bin/sh must be an essential package as only
>> way to make sure it is always present. That is clearly wrong and we
>> have mawk/gawk as a real life example of having something always
>> installed (awk) while still keeping the choice open.
>
> I think we already told that we do not want to use update-alternatives for
> the /bin/sh symlink.
>
>> 2) You are bloating the system and essential packages list
>
> The size increase caused by dash is largely compensated by the other
> speed benefits. Calling that bloat is counter-productive discussion.
> If you really believe it's bloat, you should just try to remove
> bash from the essential packages (it's doable in the long term).
>
>> Will it eventually be policy that essential/required/standard packages
>> must not depend on bash? Because as long as something in the core
>> packages depends on bash it will remain non removable.
>
> Go push forward that policy item. You don't get to enforce someone else
> pushing it for you as a precondition for their work.
>
> Cheers,
> --
> Raphaël Hertzog
For counter arguments please read the previous thread.
I just wanted to comment on the talk as I felt that it sold things it
plain does not deliver or alter from the current situation as brand
new achievements.
Don't get me wrong. I'm all for removing bashism in /bin/sh scripts
and there has been some great work done there and I'm all for
replacing bash with a smaller and faster shell as /bin/sh.
I just would like it to be even better. And I haven't seen any real
constructive discussion about different methods of providing
/bin/sh. Mostly just angry replies along the lines of "We don't want
to break things. We do it this way." without disclosing what or why
things would break.
There seems to be one group of people that would like more flexibility
(including the option of keeping bash as /bin/sh even in the long run)
and the other group being dead set on the dash plan. And no dialog
between the groups. Both sides (and feel free to include me there too)
stay in their corner and say "nay" to each other. It is sad that we
can't discuss the merrits and problems of proposals rationally and
work out a solution that works for all.
MfG
Goswin
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