svn commit: r367692 - head/sys/sys

[Cy Schubert]

In message <0015bc22-4568-93cc-5c77-e97c4f5e215c at FreeBSD.org>, John Baldwin 
wri
tes:
> On 11/14/20 2:34 PM, Warner Losh wrote:
> > true, but a version bump forces that and versions are cheap enough...
>
> Strictly speaking, version bumps don't force anything to recompile, they
> just ensure that newer modules won't load on older kernels.  In this case,
> the change to sys/ucred.h will result in sys/ucred.h's mtime changing so
> that any kernel modules being built via NO_CLEAN=yes will rebuild ok.
>
> I'm not quite sure where this mantra that version bumps force rebuilds
> came from, but they don't.  It's true that since it lives in <sys/param.h>
> and most things include that, it mostly forces a rebuild, but that's
> mostly a side effect, not due to explicit magic around __FreeBSD_version.

Any update to sys/param.h causes the rebuild of any object that depends on 
the header file. It also causes any poudriere jail built on -CURRENT to 
delete all its packages and restart from scratch.

Poudriere assumes it means ABI or API changes whereas version bumps could 
simply be markers of notable change that may not affect the ABI. In which 
case poudriere package rebuilds are gratuitous.


-- 
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy at nwtime.org>    Web:  https://nwtime.org

	The need of the many outweighs the greed of the few.