Hi folks, Following some discussion with Marco d'Itri about inetd, I'd like to put forward some more general thoughts on virtual package handling for some comments.
Currently, virtual packages (such as mail-transport-agent) cannot be specified by themselves. They can only be used in combination with a non-virtual package which provides the default implementation. For example: Depends: exim4 | postfix | mail-transport-agent or Depends: exim4 | mail-transport-agent This means that 1) Each package depending on a virtual package must specify a real package 2) There is no central policy defining which package is the default implmentation--each package could specify a different default 3) Changing the default is a lot of work--every reverse dependency must be updated. For the case of mail-transport-agent, this could be simply solved by the creation of a mail-transport-agent-default package. This would be an empty package, doing nothing but providing this dependency: Depends: exim4 | mail-transport-agent All packages wanting to depend on mail-transport-agent need only have Depends: mail-transport-agent-default When exim4 becomes exim5, or some other MTA, only the mail-transport-agent-default package would need updating. For the new inet-superserver virtual package, there are potentially over 120 packages which would need to add Depends: openbsd-inetd | inet-superserver However, I feel that this is too many places to hardcode the openbsd-inetd default (Marco d'Itri does not believe this is worth the effort, but I personally think that it will potentially prevent a lot of future effort). Here, I think a means of specifying a distribution-wide default is much better than requiring each package to separately specify it. For this case, I would like to create an inetd-default (or inet-superserver-default) package, which would simply be Depends: openbsd-inetd | inet-superserver and all inetd-requiring packages would just use Depends: inetd-default See http://people.debian.org/~rleigh/inetd-default_1.tar.gz and http://people.debian.org/~rleigh/inetd-default_1.dsc There are some other useful side-effects: Custom Debian Distributions can easily change the -default package to customise the distribution defaults. Example: Scott Remnant recently blogged on -planet about the "upstart" init/cron/inetd replacement being developed in Ubuntu. This would replace openbsd-inetd, and with this scheme would require a one-line change to a single package. Other CDDs might want to use other inetds, e.g. xinetd, or a "null" inetd which does nothing. For MTAs, other distributions might want to switch from exim4 to a more lightweight MTA (or even a "null" MTA for minimal systems). This system would allow that to be simply and easily configured. Regards, Roger -- .''`. Roger Leigh : :' : Debian GNU/Linux http://people.debian.org/~rleigh/ `. `' Printing on GNU/Linux? http://gutenprint.sourceforge.net/ `- GPG Public Key: 0x25BFB848 Please GPG sign your mail.
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