svn commit: r193241 - in head: . sys/sys

[M. Warner Losh]

In message: <20090604151959.GA26524 at zim.MIT.EDU>
            David Schultz <das at FreeBSD.org> writes:
: On Mon, Jun 01, 2009, Ken Smith wrote:
: > It was noted we're close to running out of numbers we can use before we
: > hit code freeze and the branch for the release.  Since we're entering
: > code slush at the end of today in theory all changes that would warrant
: > a bump in __FreeBSD_version are supposed to be done.  But it wouldn't
: > surprise me if we have one or two or so things that come along between
: > now and when we hit code freeze and the branch.  So we need to be a bit
: > conservative with this.  Please be sure to coordinate anything that
: > might require a bump in __FreeBSD_version with re@ from now on.  If it
: > turns out things do come along that require bumps we'll need to "batch
: > them up" having one bump represent several changes.
: 
: To avoid this sort of problem in the future, how about adding a
: digit to __FreeBSD_version in 9-CURRENT?  Admittedly, a lot of the
: bumps in 8.X were probably unnecessary, but it's good that people
: are being cautious and documenting their incompatible changes.

We can avoid this problem by not being so bump-happy.

Adding an extra digit was painful when we did it before.  A number of
subtle things broke (like the output of file).

Part of the problem here is that we want to ship FreeBSD 8.0 as
'800100' which is just historical convention:

 * scheme is:  <major><two digit minor>Rxx
 *		'R' is 0 if release branch or x.0-CURRENT before RELENG_*_0
 *		is created, otherwise 1.

We could easily up that to '5' for the release so we have 499
entries. There aren't so many things that depend on this convention in
the tree (I couldn't find any in a quick, informal survey).

 * scheme is:  <major><two digit minor>Rxx
 *		'R' is less than 5 if release branch or x.0-CURRENT
 *		before RELENG_*_0 is created, otherwise 5 or greater.

I think is the only change we really need to make.

: Better yet, we could automate the process somewhat and use
: something like the major version of FreeBSD concatenated with the
: SVN revision in lieu of __FreeBSD_version.

I think this would be worse.  First, external trackers would have
difficulty updating this.  Second, __FreeBSD_version is used to
indicate kernel ABI points (at least recently, this is lame and should
be reverted for the RELENG branch, but I digress).  Third, ports use
it to determine where we are and build things differently.  I think
this would complicate their lives and make documenting the points more
difficult.

This is one of those things that I don't think should be totally
automated.

Warner