Re: Bug#273093: dpkg: Unpredictable behavior when two packages want to divert the same file
reassign 273093 debian-policy
retitle 273093 policy: Document interactions of multiple clashing package diversions
severity 273093 wishlist
thanks
Hi!
On Thu, 2004-09-23 at 22:25:58 +0200, Frank Küster wrote:
> Package: dpkg
> Version: 1.10.23
> Severity: normal
> Feel free to reassign this to debian-policy if you think this isn't
> dpkg's fault...
Doing this now.
> If the two independent packages bar and baz both dpkg-divert the file
> /usr/share/foo/bla/brm of package foo, only one of both can "get" the
> diversion. And it will be the first package that can successfully
> register the diversion, the second will just get
>
> Unpacking baz (from .../apt/archives/baz_1.0-3_all.deb) ...
> Leaving `diversion of /usr/share/foo/bla/brm to /usr/share/foo/bla/brm.foo by bar'
> Setting up baz (1.0-3) ...
>
> and even when bar is removed, no record is made that baz wanted to add
> it's own diversion.
This sould only happen if both diversions are idential, which would be
fine, but most commonly if two different packages divert a file then the
--package argument will be different which will make dpkg-divert error
out pointing out there's a clash with an existing diversion, and this
has (supposedly) been this way since the initial dpkg-divert
implementation.
> This can lead to unpredictable behavior, because it's just a matter of
> chance which package is installed first by a user.
>
> It seems there is no mention of the problem in policy (or the
> developer's reference). It also seems I don't like the diversion
> mechanism too much... Anyway, making this predictable and defined
> seems ;-) to be difficult, both by implementing checks and registries
> in dpkg, or by policy decisions. I have no proposal to make,
> unfortunately.
>
> And while we're at it, and a copy goes to debian-policy@l.d.o,
>
> ,----
> | You should not use `dpkg-divert' on a file belonging to another
> | package without consulting the maintainer of that package first.
> `----
>
> Not only that a warning about multiple diversions is missing here:
> This should be noted down somewhere in the source package. There are
> NMUs, packages are orphaned etc., and information like this can easily
> be lost.
I don't see anything to fix here in dpkg, this is how diversions work,
that's just it. It could of course be documented more clearly in
policy, and for example mention that different packages diverting the
same file should Conflict with each other.
thanks,
guillem
Reply to: