Xavier schrieb:
On Sat, Sep 12, 2009 at 1:21 PM, Marc - A. Dahlhaus <mad@wol.de> wrote:
Another problem with hooks and the points on which they should be executed is that if you have a large transaction in which some packages add hooks that are needed for packages that are installed in the same transaction need to be parsed on installation time to give you the option to run the hooks on the point they should be executed. Also what about a package that wants hook X needs to be installed before the hook X is added by another package? Would be a classic chicken-egg problem i think. Trigges like i proposed them don't have this problem as they get executed after the transaction is completed. At this point all triggers are where they should be.
We also wanted to support actions which are only executed after the transaction is completed : http://wiki.archlinux.org/index.php/User:Allan/Pacman_Hooks#Types_of_Hook
The differences if that they would be triggered automatically by a file, instead of manually triggered by the packages themselves.
I actually have read the text on the wiki and i know that there is a transaction hook mentioned there. Did you think about the case where a common task could be wanted if there isn't any filename based rule that could fire it up? An example could be that a package adds some functionality that is an optional dependency for a job. If the dependency is not installed on the jobs first execution than some thinks are not done. If the optional dependency get installed at a later point it could ask for the trigger of the dependency and activate the missing things. I argue that they should be differently handled because of situation where the "file X got installed so we need to start Y" will not work. Marc