DEB_UN{DIVERT,REMOVE}_FILES always conditionalizes on upgrade version

[broder]

The automatically generated maintainer script code generated by both DEB_UNDIVERT_FILES and DEB_UNREMOVE_FILES always checks and conditionalizes the undiversion on the version being upgraded from.

This isn't always desirable, as sometimes our reasons for removing diversions are tied to other factors.

For example, in kerberos-config, we want to remove the krb.conf diversion if you're upgrading to a version of kerberos-config on a krb4-less platform.

A mechanism to remove a diversion iff it exists already would be sufficient for all the cases we've currently run into. I'm thinking something like setting DEB_UNDIVERT_VERSION_file = all for the interface.

[broder]

As a jumping-off point, I've attached a patch that I believe will serve our purposes of undoing any pre-existing diversion if DEB_UNDIVERT_VERSION_file=all.

I haven't tested it yet, but wanted to go ahead and post it for others' perusal.

[andersk]

What about DEB_UNDIVERT_VERSION_file = $(DEB_VERSION)?

[broder]

Eww. Eww. But...that might work.

That being said, two thoughts:

1. You will still get spew both from the OMINOUS WARNING and from dpkg-divert attempting to remove a diversion that's no longer in place. It'd be nice to suppress that
2. This won't solve the kerberos-config problem, which is that I specifically want to remove a diversion but not a removal and vice-versa.

[broder]

Ooh - there's an even more fun screw case with using $(DEB_VERSION)

Say that package-1 undiverts a file with DEB_UNDIVERT_VERSION_file = $(DEB_VERSION), then package-2 starts diverting the file.

The next time package-1 gets upgraded, it'll delete the symlink without undoing the diversion.

[broder]

Is there actually a particularly compelling reason for having DEB_UN{DIVERT,REMOVE}_VERSION at all, instead of just always testing if the diversion you're removing is in place?

I guess there's a performance argument? Is dpkg --compare-versions actually enough faster than dpkg-divert --list to care? My inclination is no.

[broder]

Ok. I just attached a new version of attachment:config-package-dev_trac549.diff that fixes several typos and errors and such.

I've done what I think is sufficient testing. I created a 1.0 package that diverts a file, and a 1.1 of the same package that undiverts it. I also created a 1.1 package that removes a file, and a 1.1 that unremoves it.

For each of those, I tried

• Installing the 1.0 and uninstalling the 1.0
• Installing the 1.0, upgrading to 1.1, and uninstalling 1.1
• Installing the 1.1 and uninstalling the 1.1

I can't come up with any other use cases that might need testing, so I think this is all done.

[jdreed]

Can we get this patch taken soon?

[jdreed]

Committed in r25060-r25063.

   debathena / cpd / andersk  21:59  (Anders Kaseorg)                           
       Sponsorship request sent to spang.   

[geofft]

I've built and uploaded config-package-dev 4.12 into the Debathena -development repositories. In other news, it's in Wheezy and Oneiric.

[jdreed]

This moved a while ago.