Hi, Steve Langasek wrote:
> So in this case the pre-dependency > should *not* be set, as it only serves to complicate the upgrade path. I think this example might deserve a closer look. Documentating the required dpkg version seems useful for backporters and others who would use the package in unusual situations. What dpkg does: Since depisok() is called with allowunconfigd == true, to dpkg a Pre-Depends is just like a Depends, except that at unpack time dpkg checks that the depended-on package: - has been configured before - satisfied the version relation the last time it was configured - has not been removed since then. These conditions are trivially satisfied when unpacking a package in wheezy. The pre-dependency would have no effect beyond a Depends relation (and in particular, would be safe). What apt, aptitude do: I don't know. Do they allow an already satisfied Pre-Depends to complicate the upgrade path? IIRC dpkg, as an essential package, always gets upgraded first anyway, but I am not so familiar with this code. What policy allows package managers to do: Policy is aligned with what dpkg currently does. What future policy allows: Bug#593177 brings the possibility of change. In the extreme case the meaning of Pre-Depends could change to "the depended-on package and its dependencies must be configured at the currently unpacked version", which would make upgrade impossible in the following case. - libc6: Pre-Depends: dpkg (>= ancient). - dpkg: Pre-Depends: libc6. Luckily, bug#593177 can probably be addressed with less dramatic changes. Conclusions: I could go either way on this. On one hand, versioned Pre-Depends on essential packages in the previous release's version seem to be harmless with current tools. On the other hand, as Steve mentioned, decreasing the number of pre-dependencies in the archive is good for everyone's sanity. Hope that helps, Jonathan -- 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/20110306002627.GA16386@elie
