Web lists-archives.com

Re: Unsustainable debian/rules as official build entry point?




Guillem Jover writes ("Unsustainable debian/rules as official build entry point?"):
> Given the above, and that these are clear regressions, it seems
> obvious to me that we are (collectively) not checking/using debian/rules
> as the official build entry point interface.
> 
> And I've got to question whether we should keep supporting it or just
> declare dpkg-buildpackage to be that entry point.

tl;dr: I think I agree with your suggestion but I would definitely
  express it rather differently.


There are two entry points which are relevant:

1. The interface provided by packages.
2. The interface consumed by programs which want to build packages.

Up to now, both of these have been, officially, the same:
debian/rules.

But for purpose 2 most programs invoke dpkg-buildpackage now.  This is
because the official interface 1 keeps becoming more complex,
particularly because of backward compatibility requirements.

The compatibility and protocol negotiation functionality in
dpkg-buildpackage, where dpkg-buildpackage arranges to work with new
packages in new ways and old packages in old ways, becomes harder and
harder to reproduce.  So de facto, most consumers of source packages
consume them via dpkg-buildpackage.

I think there is a lot of value in interposing a common
compatibility/adjustment layer between the two interfaces I mention
above.  So I would support a proposal to official declare that
programs which want to build (unrelated) packages should do so via
dpkg-buildpackage.

However:

I would _not_ support a proposal to abolish the package-provided rules
interface as de-jure standard.  It's just that this standard would
gradually lose its other consumers.  After there is only one consumer
it will be somewhat easier to change it.

Additionally, although there being one consumer makes it seem as if we
could just add new mandatory features to packages (ie, changes which
require new dpkg-buildpackage), I don't think we should do that.

It is important for backporting, downstreams, etc. etc., that old
versions of dpkg-buildpackage can build new packages.

Important consequences of my views include:

* The package-provided rules interface needs to remain managed as part
  of policy (and to continue to have a controlled approach to updates,
  etc.).

* The interface is not *defined by* dpkg-buildpackage: ie it is still
  possible for dpkg-buildpackage to have a bug where it does not
  implement the de-jure interface.

* Packages may still need to work around bugs in old versions of
  dpkg-buildpackage; conversely, new versions of dpkg-buildpackage may
  need to work around bugs in old packages.

* For a long time, packages should try to be compatible with old
  builders which invoke rules directly, even old builders other than
  dpkg-buildpackage.


I think you will probably agree, but I wanted to set it all out.

Ian.