Re: Bug#489771: New Build-Options field and build-arch option, please review

[Goswin von Brederlow <goswin-v-b@web.de>]

Russ Allbery <rra@debian.org> writes:

> Raphael Hertzog <hertzog@debian.org> writes:
>> On Wed, 10 Sep 2008, Bill Allombert wrote:
>
>>> I like to say I concurr with Russ. There are some much difference
>>> between packages that distributions wide default does not make sense.
>>> Such change would rather lead me to hardcode values of
>>> DEBIAN_BUILD_OPTIONS in debian/rules if they are used blidly.
>>
>> But more and more people want to be able to change distribution wide
>> default: Emdebian wants to enable "nodocs" and "nocheck" by default,
>> other want to be able to enable hardening options by default and I agree
>> with them that official support for such a facility is desirable.
>
> So they should set DEB_BUILD_OPTIONS in the environment.  That's what it's
> for.  I don't have any objections to that, or even to doing it via
> dpkg-buildpackage.

Setting the environment on a distribution wide level is ugly and
fragile. Too many users will reset the environment in their .bashrc.

Instead the idea was to have a vendor (set in
/etc/dpkg/origins/default) that will be exported into DEB_VENDOR if
unset and also set DEB_BUILD_OPTIONS to the vendor specifics defaults.

The bugreports relevant for this have 2 solutions:

1) make dpkg-buildpackage use (or tool with equivalent environment
   setting up capabilities) mandatory

2) have debian/rules call something to set DEB_VENDOR and possibly
   more

   E.g. 'include /usr/share/dpkg/Makefile.dpkg'
   or   'DEB_VENDOR        ?= (shell dpkg-vendor -qDEB_VENDOR)
         DEB_BUILD_OPTIONS ?= (shell dpkg-vendor -qDEB_BUILD_OPTIONS)

The argument against 2 is that is requires every source to be modified
if they want to support vendors whereas 1 only needs some small
modification to dpkg-buildpackage to support calling arbitrary targets
in debian/rules and a change in policy making its use mandatory.

> My objection is specifically to having dpkg-buildpackage set a variety of
> environment variables *by default*, and then telling package maintainers
> that they should rely on those environment variables being set in the
> default case.  That breaks the debian/rules interface and requires that
> all package builds go through dpkg-buildpackage.  Having dpkg-buildpackage
> set environment variables in the non-default case like Emdebian is not a
> problem, since for Emdebian builds (for example) Emdebian can decide that
> using dpkg-buildpackage or setting the environment variables manually is
> required.  There is no existing precedent, and they can make that rule
> from scratch.

Then you have one interface for Debian and one interface for every
other vendor including ubuntu (or option 2 above).

> My concern is for the default build where there *is* an existing precedent
> that debian/rules build should work sanely, not for support for special
> cases like that where the existing debian/rules interface already doesn't
> do the right thing without additional help.
>
> If you are going to go down this path of having dpkg-buildpackage set up
> an environment that package maintainers should rely on, you or someone
> else on the dpkg team needs to make a debian-devel-announce post making it
> clear that debian/rules build is no longer a supported interface for
> building packages and using dpkg-buildpackage is required for consistent
> behavior.

Plus a note in policy clarifying that debian/rules is only an
interface for dpkg-buildpackage but not users.

> Right now, I don't think most Debian Developers have any idea what the
> implications of these changes are.

I have to say i verry rarely do not use debuild. And 99% of the
exceptions are calling debian/rules clean.

MfG
        Goswin

PS: with dpkg-buildpackage setting env vars like it does now you
already have a verry confusing situation.