Re: [gentoo-dev] BUILDROOT concept (was Re: [gentoo-dev] ROOT variable)

On Fri, Apr 23, 2004 at 03:45:52PM -0400, Paul Smith wrote:
> %% david@×××××××××.com writes:
>
>   >> Mm.  But of course, this will only work if your embedded system just
>   >> happens to be the same architecture as your build system... which I
>   >> think is not a good restriction to make.
>
>   d> I still don't see how `ROOT=/tmp/foo emerge blah` doesn't solve
>   d> your problem.
>
> Maybe I'm misreading the code, but from what I can see, when you set
> ROOT it only changes where RDEPEND packages are searched for.
>
> It does _NOT_ change where DEPEND packages are searched for: they're
> still searched for on the native system not in the ROOT system.  If the
> native system and the root system are very different, that doesn't seem
> like it can work properly.
>

see catalyst snapshots model.  Specify whatever custom portage tree you want
to your hearts content.

>   >> I don't see how this solves the problem.  First, the point is to
>   >> allow multiple "build" images, which this does not do, since it
>   >> still uses the local host for all DEPEND information.  I don't want
>   >> to have to update (or downgrade!)  my local host's installation of
>   >> packages just to build a ROOT with a different setup!  Second, the
>   >> ROOT is not a real Portage system here: all the Portage database
>   >> information, etc. is on the local system.  Third, this still won't
>   >> work if the ROOT target is to be run on different hardware than the
>   >> build system.  Etc.
>
>   d> I don't understand what you mean by 'portage database information'.
>   d> Maybe you could explain more, becuase I don't see any problems here
>   d> either.
>
> If you look at the code in emerge (this is from the latest Portage CVS)
> you'll see things like this:
>
> 	if myroot=="/":
> 		mydep["/"]=edepend["DEPEND"]+" "+edepend["RDEPEND"]
> 		if not self.select_dep("/",mydep["/"],myparent=mp,myuse=myuse):
> 			return 0
> 	else:
> 		mydep["/"]=edepend["DEPEND"]
> 		mydep[myroot]=edepend["RDEPEND"]
> 		if not self.select_dep("/",mydep["/"],myparent=mp,myuse=myuse):
> 			return 0
> 		elif not self.select_dep(myroot,mydep[myroot],myparent=mp,myuse=myuse):
> 			return 0
>
> IIUC, this shows that if ROOT is not the default (is not "/") then
> emerge will check the native system for the DEPEND requirements and
> check the ROOT image only for the RDEPEND requirements.
>
> Also, you'll see many instances of code like this:
>
> 	mylogfile=open("/var/log/emerge.log", "a")
>
> which is obviously going to be updating the emerge.log file on the
> native system, not in the ROOT image.  And this:
>
> 	profilever=os.path.basename(os.path.normpath(os.readlink("/etc/make.profile")))
>
> which shows Portage checking the profile on the native system, not the
> one in the ROOT system.  I do see that the ebuild cache is kept in ROOT,
> so that's good (originally I thought it wasn't there).  But there is
> this suspicious looking bit in portage.py, although it might be a bug:
>
> 	worldlist=grabfile("/var/cache/edb/world")
>
> I would think that this should be using the world file in the ROOT, not
> the native system.
>

again catalyst will acheive this for you.  Specify whatever profile
you want in the spec file.

>
> More generally, what I want to be able to do is build for a target
> (ROOT) a specific set of packages and versions _without_ having to
> modify my physical system in any way.  I don't want the build of the
> ROOT to have any relationship to what I have installed on my physical
> system.  If I want ROOT to have a version of a package that doesn't work
> with a newer version of GTK or whatever, I don't want to have to
> downgrade the version on my physical system in order to build that
> ROOT.  Maybe I want to create a ROOT system with a KDE desktop but don't
> want KDE installed on my build system.  Etc.
>
> Right now the construction of the ROOT is accomplished by a combination
> of stuff on the physical system and stuff in the ROOT image.
>

again catalyst will solve your problems.  If you want I can go into
more detail.  Speaking of... if zhen is out there listening
somewhere.. when is the new catalyst going to come out ?

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