Hi! On Fri, 2010-04-23 at 10:51:56 +0200, Goswin von Brederlow wrote: > Package: debian-policy > Version: 3.8.4.0 > Severity: normal
> to test the actual behaviour of dpkg for this situation I created the > following 5 packages: [...] > Test 1 > ====== > > I start with version 1 installed and update to version 2/2b/2c without > problems. Then on downgrade: > m...@frosties:~/t% sudo dpkg -i foo_1_all.deb > dpkg: warning: downgrading foo from 2 to 1. > (Reading database ... 176361 files and directories currently installed.) > Preparing to replace foo 2 (using foo_1_all.deb) ... > Unpacking replacement foo ... > dpkg: error processing foo_1_all.deb (--install): > trying to overwrite '/usr/share/doc/foo/foo.control', which is also in > package bar 0:2b > Errors were encountered while processing: > foo_1_all.deb > > SEE http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=20471 No, this is #568566, and fixed in 1.15.7 with: <http://git.debian.org/?p=dpkg/dpkg.git;a=commit;h=418e1fc0> I found out this bug some weeks ago by code staring, and only matched it against an actual bug report recently, initially thought it would fix some failing test-cases about disappearing packages in the dpkg's pkg-tests.git functional test suite, but it ended up being something different. This was “introduced” in dpkg 1.13.2 (2005-03-18) when fixing #164595 by forgetting to handle the versioned downgrade case, for something that had not been supported before. > In conclusion: > ============== > > On downgrades using Replaces with Breaks triggers a long standing dpkg > bug or can cause files to disapear. So it might indeed be wise for > policy to prohibit the use of Breaks for file conflicts. Even if the > dpkg bug is fixed it still risks loosing files when reverting a > partial upgrade and downgrading to the old versions. There's the problem with downgrades and versioned Replaces, and there's the other problem with disappearing the wrong replaced/replacing package on reverse installation order and losing track of package ownership of files, fixed also in 1.15.7 with: <http://git.debian.org/?p=dpkg/dpkg.git;a=commit;h=0958a9f9> Neither of these are triggered by Breaks nor Conflicts. These test-cases can be found in: <http://git.debian.org/?p=dpkg/pkg-tests.git;a=tree> regards, guillem -- To UNSUBSCRIBE, email to debian-policy-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20100425164556.ga22...@gaara.hadrons.org
