[pacman-dev] Adding a new config file to a package (e.g. mercurial file conflict)

[Dave Reisner]

On Thu, Jul 14, 2011 at 12:28:31PM -0500, Dan McGee wrote:
> I did an -Syu on my Arch box today, which updated Mercurial, and the
> new package contains a /etc/mercurial/hgrc file. I had already created
> one on my system, and the old package did not contain one, so I got a
> file conflict.
> 
> (54/54) checking package integrity                 [######################] 100%
> (54/54) checking for file conflicts                [######################] 100%
> error: failed to commit transaction (conflicting files)
> mercurial: /etc/mercurial/hgrc exists in filesystem
> Errors occurred, no packages were upgraded.
> 
> 
> So instead, I had to -Sf the package, which installs the file with a pacnew:
>
> (1/1) checking package integrity                   [######################] 100%
> (1/1) checking available disk space                [######################] 100%
> (1/1) upgrading mercurial                          [######################] 100%
> warning: /etc/mercurial/hgrc installed as /etc/mercurial/hgrc.pacnew
> 
> 
> This behavior is a bit...odd. We don't like people using -f, and they
> are trained to assume the worst, so most would not expect the backup
> logic to still kick into effect. A pactest is below, but I'm asking
> for thoughts on expected behavior in this case. Many possibilities
> listed for completeness, some of which are just plain dumb.
> 
> 1) Keep as is with file conflict error, require -Sf, keep backing up
> file to pacnew
> 2) Keep as is with file conflict error, require -Sf, don't backup
> (this is stupid)


> 3) Don't error at all, treat as a normal backup case except pretend
> old file is the same as /dev/null (aka empty).

This is where I sit. You shouldn't have to force the install, and the
new file from the backup array should be dropped in place with a .pacnew
extension. IMO, you get the best user experience going this route --
you don't need to go out of your way to do the upgrade, and there's
notification about the new file being dropped in. I don't think there's
any need to create a different message. It's sort of a special case, but
I don't think it needs any special handling.

d

> 4) Same as (3), but make the pacnew warning message slightly
> different, e.g. "%s is new in package, installed as %s" or something.
> 5) Something like (3) or (4) but don't even treat it the same as an
> empty file, treat it as never matching anything.
> 
> My vote is 3 or 4, not that we are a democracy. :)
> 
> -Dan
> 
> 
> self.description = "Upgrade a package, with a file entering the pkg in 'backup'"
> 
> lp = pmpkg("dummy")
> lp.files = ["usr/bin/dummy"]
> self.addpkg2db("local", lp)
> 
> p = pmpkg("dummy", "1.0-2")
> p.files = ["usr/bin/dummy",
>            "etc/dummy.conf"]
> p.backup = ["etc/dummy.conf"]
> self.addpkg(p)
> 
> self.args = "-U %s" % p.filename()
> 
> self.addrule("PACMAN_RETCODE=0")
> self.addrule("PKG_VERSION=dummy|1.0-2")
> self.addrule("!FILE_PACSAVE=etc/dummy.conf")
> self.addrule("FILE_PACNEW=etc/dummy.conf")
> self.addrule("FILE_EXIST=etc/dummy.conf")
>