[pacman-dev] Shabang in scripts

[Pierre Neidhardt]

On 14-03-02 19:42:30, Allan McRae wrote:
> On 02/03/14 19:19, Pierre Neidhardt wrote:
> > On 14-03-02 10:01:32, Allan McRae wrote:
> >> On 02/03/14 06:14, Pierre Neidhardt wrote:
> >>> This maybe a futile question, but not much to lose here so I'm still asking:
> >>> should we let the autotools change the path of the interpreter in the shabang of
> >>> the different scripts? (See makepkg and so on.)
> >>>
> >>> Actually, according to
> >>>
> >>>       https://wiki.archlinux.org/index.php/DeveloperWiki:Bash_Coding_Style
> >>>
> >>> it is said that the interpreter should be /bin/bash, not /usr/bin/bash. The
> >>> latter being far less common. Note that the source files are properly set to
> >>> /bin/*, only the autotools change them to the realpath of the build system.
> >>>
> >>> This is really a minor issue, but I believe that switching it back to /bin/bash
> >>> would remove one portability problem for most systems. For instance, to run
> >>> makepkg on a non-Arch system, we download the 'pacman' binary package first,
> >>> from which we extract the 'makepkg' and the 'makepkg.conf' files. Since the
> >>> package was built on an Arch system, the shabang is set to /usr/bin/bash. On
> >>> non-Arch system, we usually need to make to change the shabang back to
> >>> /bin/bash.
> >>>
> >>> What do you think?
> >>>
> >>
> >> Bash is not found in /bin in various BSDs.
> >>
> >> Allan
> > 
> > 
> > Right, I was mentionning "most systems", this is no universal solution of
> > course. But having this rule in the wiki does not make much sense if the shabang
> > is automagically generated.
> 
> Pacman development does not care about the Arch wiki.  In fact...  as
> far as I know, Arch development does not care about the bash style wiki
> page.

Shouldn't we have a coding style for bash? The HACKING file only mention a
coding style for C. There is quite a big amount of bash code in the pacman
sources, it could be useful. The wiki page looks rather fine to me.

> > By the way makepkg has other portability issues on *BSD systems. So far I could
> > spot these:
> > * bsdtar should be tar. We would need a wrapper function then.
> 
> I only have freebsd to test with, but libarchive installed bsdtar.  In
> fact, /usr/bin/tar is a symlink to bsdtar.

My bad.

> > * @SEDINPLACE@ is not portable once autotooled, not standard, and not the right
> >   way to do it anyway. 'ex' should be used instead. For instance (not tested)
> 
> Building pacman/makepkg on freebsd, I get sed lines like:
> 
> sed -i "" "s:...:...:" "$BUILDSCRIPT"
> 
> and I have tested that it works as intended.

Yes it works, but this is no good practice, see there:

  http://mywiki.wooledge.org/BashFAQ/021

> >   ex -sc "%s:^pkgver=[^ ]*:pkgver=$newpkgver:|xit" "$BUILDFILE"
> > 
> > But maybe the case of *BSD systems is not extremely relevant since they all have
> > a portage tree and makepkg would not be of much help. In which case the shabang
> > to /bin/bash makes more sense! :p
> 
> Except for the (at least two) projects creating an Arch like BSD.
> 
> If you have the tools installed to run makepkg on your system and build
> almost anything, you have the tools necessary to build pacman.

Well, that's a good point :)

> Copying a prebuilt makepkg over to a different system is not how you start a
> bootstrap.
> 
> Allan

-- 
Pierre Neidhardt

Academicians care, that's who.