[arch-general] PKGBUILD parser

[Allan McRae]

On 10/05/10 02:06, Loui Chang wrote:
> On Sun 09 May 2010 16:21 +0200, Xavier Chantry wrote:
>> On Sun, May 9, 2010 at 2:44 PM, Allan McRae<allan at archlinux.org>  wrote:
>>> Sourcing is dangerous if the PKGBUILD is from an untrusted source.  It also
>>> fails with package splitting...
>
>> But I just had an idea now, if we're thinking about AUR use case :
>> makepkg --source could generate a suitable and parsable file providing
>> all information that AUR needs, and ships that next to the PKGBUILD in
>> the source tarball. Does that sound crazy ?
>> This would not fix the problem now, but it could fix it eventually,
>> when most pkgbuilds are re-submitted. Or this parsable file could be
>> generated for all pkgbuilds in a row, just for the conversion, in a
>> chroot/jail on a machine not in production.
>
> Yeah I've thought about this as well. Source packages could have a
> similar format as binary packages with a .PKGINFO file to present the
> metadata in an easily parsable format.
>
> You can read some of my incomplete brainstormings here:
> http://louipc.mine.nu/arch/%5BRFC%5D-PKGINFO-in-srctargz
>

I am told I like to be really negative anytime this is bought up...  it 
is not deliberate, I just see the barriers to this working.  So here we 
go!  I know you have pointed out some problems already and this is 
related.

makepkg does not actually parse any of the splitpkg overrides until 
build time. How do we get the packaging variable overrides without 
actually making the package (and on every architecture)?  We would need 
to extract the needed fields from the package functions somehow.  So 
that brings us back to needing to hack a bash parser in makepkg or to 
actually require the package building to take place before you can 
create a source package.  And this is not restricted to package splitting...

e.g.

pkgname=foo
...
# depends not needed at make time
# depends=('bar')
...
package() {
   depends=('bar')
}

Welcome to the world of makepkg hacks...   And do not think such hacks 
are not used.  The old klibc PKGBUILD generated a provides array in the 
build function on the basis of a file name only available at the end of 
the build process.

The joy of PKGBUILDs is that they are so flexible.  The problem with 
PKGBUILDs is that they are so flexible.

Allan