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Re: bash exorcism experiment ('bug' 762923 & 763012)



Russell Stuart <russell-debian@stuart.id.au> writes:

> Not really.  I'm about documentation reflecting reality.  Think of
> putting an electrical component whose documentation says its 200 degrees
> on a motherboard, only to find it fails at 190.  When you ask why, is
> "well we design it for 200, but only test it to 180" a satisfying
> answer?

> You have convinced me that in this case it's going to have to be that
> way, so my prejudices notwithstanding.  I've rationalised the pain away
> by deciding it's no so bad as any competent programmer could see that is
> it only tested to 190 regardless of what the standards say.

Yeah, I do get that discomfort.  I would love for Policy to be more
accurate about what's actually happening in the archive.  I just don't
have much (any) time at the moment to try to push the wording in that
direction.

> It's attractive because makes Policy more relevant - but only because of
> that.  Now that I think about it, switching pbuilder to posh would be
> almost as good.  Any additional pain would not be worth the effort.

That would be interesting, although I think that would mostly pick up
build issues, which are somewhat different from the issues encountered
when running the packages on a system.  What we'd really like is something
like running autopkgtest tests with posh as a shell, but with much better
coverage than we currently have.

We're much better at testing our build processes than we are at testing
the constructed packages, at least currently.

> If Debian was going to switch to another shell, I'd vote for the one in
> busybox.  That's because on desktop machines it doesn't matter, but on
> embedded architectures it does - and they use busybox.  So switching to
> busybox would extend Debian's reach.

Wouldn't that pose a bunch of problems due to the huge number of built-ins
in busybox, most of which don't work the same way as the regular program?

>> If the speed is comparable

> Here are two benchmarks.  I did others. These demonstrate the extremes:

>         $ time dash -c 'i=0; while [ $i -lt 10000000 ]; do echo -n; i=$(($i + 1)); done'
>         real	0m16.695s
>         user	0m16.684s
>         sys	0m0.000s
>         $ time posh -c 'i=0; while [ $i -lt 10000000 ]; do echo -n; i=$(($i + 1)); done'
>         real	0m41.899s
>         user	0m41.872s
>         sys	0m0.000s

Yeah, I seemed to remember posh being much slower than dash (although that
particular benchmark is a little artificial).

> It looks like moving to dash sped Debian up a little.

That was supported by boot timings, which are a pretty good simulation of
real-world load.

-- 
Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>


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