Re: Where is %build's cd to build subdir setup come from?

[Frank Cusack <fcusack fcusack com>]

On June 20, 2007 12:23:03 PM +0200 Toralf Lund <toralf procaptura com> 
wrote:
> When doing rpm build with a common rpm spec file containing %setup etc,
> the "build" execution will start off with something like:
>
> Executing(%build): /bin/sh -e /var/tmp/rpm-tmp.84274
> + umask 022
> + cd /usr/src/redhat/BUILD
> + cd mypackage-1.0
>
>
> - where mypackage-1.0 is typically "root" of the Source0: filename,
> although it may also be specified via %setup -n or whatever.
>
> Where exactly does the command "cd mypackage-1.0" come from? I mean, by
> what mechanism does "setup" communicate to "build" that it needs to
> change to this directory before starting the actual build?
>
> I'm experimenting with a advanced (or possibly unnecessarily complex ;-))
> build configuration involving a redefinition of "setup", so I really need
> to know how exactly everything is done by default. Or differently put, if
> I redefine setup, I always end up loosing the "cd" command in question....

%setup defines %buildsubdir, which triggers the cd, however you can't set
%buildsubdir yourself and have it work.  It's a magic (unfortunate) part
of rpm.

Redefining %setup is a bad idea.

-frank