Autogen PKGBUILD from source tarball

Question

I had an idea while reading about the (lackluster) checkinstall utility:
http://asic-linux.com.mx/~izto/checkinstall/
The basic problem is that the user still needs to run ./configure, which will fail if the user is missing any dependencies.  It's a simple shell script that somewhat automates the best-case scenario for source-based package management.
But what if Arch had a tool that extracts a source tarball, parses its configure script to find compile-time and runtime dependencies (and a few flags maybe), looks at the Makefile to determine the correct variable to set the install path, and generates a default PKGBUILD from this information.  It might not always produce a working PKGBUILD, but it should produce something pretty close.
How feasible do you think this is?  Do you think this might be one more step towards empowering the user to get involved and create a first PKGBUILD?  Is this idea useless it it doesn't always produce a working PKGBUILD, or is anything better than starting with PKGBUILD.proto?

Answer 1

I once had a similar (but then again, quite different) idea. Because alot of the PKGBUILDs I wrote only differed from the prototype in $pkgname, $pkgver, $source and $depends, and I actually often filled in the latter with info from namcap after building the package, I thought; hey, why not have makepkg get the dependencies from namcap rather than $depends? And if the build process could be guessed by analyzing the source archive (gobolinux has an interesting script), you might not need to write a PKGBUILD at all!!
Your idea is probably better because you don't have to modify makepkg.
Wouldn't this be fun?:
~$ automakepkg ftp://ftp.gnu.org/gnu/wget/wget-1.10.1.tar.gz
Fetching source archive...................................Done
Extracting source archive.................................Done
Analysing source files....................................Done
Generated build instructions:
pkgname=wget
pkgver=1.10.1
pkgrel=1
depends=('glibc' 'openssl')
backup=('etc/wgetrc')
source=(ftp://ftp.gnu.org/gnu/$pkgname/$pkgname-$pkgver.tar.gz)
md5sums=('879a15cc9093796b8a5035ff0d0d25ad')
build() {
cd $startdir/src/$pkgname-$pkgver
./configure --prefix=/usr --sysconfdir=/etc
make || return 1
make DESTDIR=$startdir/pkg install
Does this look ok? [Yn]y
Let's go then, starting build()
Finished building
Do you want to install the package now? [yN]y
sudo pacman -A wget-1.10.1-1.pkg.tar.gz
Password:
A script, generate-pkgbuild which takes a source tarball as argument, would be an interesting experiment. The level of integration shown above would not be hard if we had a script that actually got the PKGBUILD right most of the time. Now, imagine a graphical interface for answering "yes" to those questions - the user would be able to download a source tarball and double-click it to install - under control of pacman!!
The idea of setting depends by analyzing $startdir/pkg after build() has finished still appeals to me though. This has a greater chance of finding the right dependencies. On the other hand, finding deps in two ways, first by the generate script, then by checking the pkg with namcap, makes it more waterproof.