[pacman-dev] Conflicts handling

[Xavier]

The pending patch [1] from Nagy for conflicts handling broke the following pactests :
sync040, sync041, sync990

These pactests are "target vs target" conflicts that pacman doesn't try to
resolve, and just stops.
Nagy's patch tried to resolve these conflicts by removing one of the two
conflicting targets. So that broke the 3 pactests above.

When trying to change the code slightly to make pacman fail in this target-target
case, the 3 pactests above now succeed, but it breaks 5 others :
sync893, sync897, sync898, sync992, sync999

These pactests are actually other kinds of target vs target conflicts.
So finally, pacman tries to auto-resolve these conflicts more often than not,
instead of just failing.

That's what I failed to see earlier, that there were different cases to
consider. Now I see at least 4 kinds of target-target conflicts.
I'm attaching 4 pactests to illustrate that.

In my opinion, pacman could always fail with these target-target conflicts.
This kind of conlicts is very rare (it doesn't make any sense to install two
conflicting targets).
However it can happen in an odd situation (see bug 7415), where a group is
splitted across several repos.
But pacman's behavior in this case is very odd anyway..

So I think it wouldn't be worse if pacman just failed, and so it would be
left to the user to fix it manually, by removing the conflicting package from
the targets, for example using --ignore.
So this would give both a more coherent behavior, and cleaner code.

If that's alright, I will try to edit (correctly this time) Nagy's patch to
behave like that. But the 5 pactests listed above will then have to be edited
accordingly (mostly changing PACMAN_RETCODE from 0 to 1).

[1] http://www.archlinux.org/pipermail/pacman-dev/2007-August/009078.html
-------------- next part --------------
A non-text attachment was scrubbed...
Name: depconflict001.py
Type: text/x-python
Size: 484 bytes
Desc: not available
URL: <http://archlinux.org/pipermail/pacman-dev/attachments/20071028/f72901e9/attachment.py>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: depconflict002.py
Type: text/x-python
Size: 508 bytes
Desc: not available
URL: <http://archlinux.org/pipermail/pacman-dev/attachments/20071028/f72901e9/attachment-0001.py>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: depconflict003.py
Type: text/x-python
Size: 317 bytes
Desc: not available
URL: <http://archlinux.org/pipermail/pacman-dev/attachments/20071028/f72901e9/attachment-0002.py>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: depconflict004.py
Type: text/x-python
Size: 341 bytes
Desc: not available
URL: <http://archlinux.org/pipermail/pacman-dev/attachments/20071028/f72901e9/attachment-0003.py>