[oe] [PATCH] bitbake.conf, freeze.inc: Add version lockdown implementation and use it by default.

[Mike Westerhof (mwester)]

Chris Larson wrote:
> For each recipe which completes a task successfully, this emits the current
> version into ${TMPDIR}/versions.conf as a PREFERRED_VERSION line.
> ${TMPDIR}/versions.conf and conf/versions.conf are automatically included,
> in that order, in subsequent builds, to provide more deterinistic builds by
> default, and to let the user make the lockdown persist via a simple cp
> command...

Excellent! This is much needed as a feature.  The usage model seems to
be a very reasonable one, and would tend to be consistent with what
users sort of expect for a workflow.

I say "sort of expect" because I think they would rather see the
management of the versions.conf file be done by bitbake.  For example,
the "bitbake crystallize" command (to choose a name) might do no build
at all, but just generate, or re-generate, the versions.conf file.  But
that's a trivial point; they'll have to remember to cp or rm
versions.conf as necessary themselves.

The only big concern that I have is that this is really quite a drastic
change in behavior for the "cookbook-type" OE user community out there
(the folks who have memorized a set of procedures to build their distro
images without any real understanding of how it works).  How do we
propose to roll out this change?

-Mike (mwester)