Javier Serrano Polo wrote: > On Wed, 30 Sep 2020 18:34:06 -0700 Jonathan Nieder <jrnie...@gmail.com> > wrote:
>> Even so, some *rough* consensus on the plan is very useful for >> helping people evaluate that first step. > > Here is a rough plan: > > 1. Policy: Packages should declare all their dependencies, even > essential ones. I agree: this is the right first step. More specifically, it's the right first three steps. https://www.debian.org/doc/debian-policy/ch-binary.html#dependencies currently says Packages are not required to declare any dependencies they have on other packages which are marked Essential (see below), and should not do so unless they depend on a particular version of that package.[4] [4] [...] If packages add unnecessary dependencies on packages in this set, the chances that there will be an unresolvable dependency loop caused by forcing these Essential packages to be configured first before they need to be is greatly increased. I'd propose that as a first step we change that to Packages are not required to declare any dependencies they have on other packages which are marked Essential (see below), but are permitted to do so even if they do not depend on a particular version of that package.[4] [4] Functionality is rarely ever removed from the Essential set, but packages have been removed from the Essential set when the functionality moved to a different package. So when depending on these packages for such functionality, it is recommended to depend on an appropriate virtual package instead. Future versions of Debian policy may encourage and then require including explicit dependencies even for essential functionality. This is helpful to users putting together ultra-minimal systems (though Debian does not support omitting Essential functionality out of the box), and it means less work is required in case the moment comes to remove some functionality from the Essential set in the future. (The next two steps would be to change that from "are permitted" to "should", and then to "must".) What do you think? Thanks, Jonathan [4] "Essential is needed in part to avoid unresolvable dependency loops on upgrade. If packages add unnecessary dependencies on packages in this set, the chances that there will be an unresolvable dependency loop caused by forcing these Essential packages to be configured first before they need to be is greatly increased. It also increases the chances that frontends will be unable to calculate an upgrade path, even if one exists. "Also, functionality is rarely ever removed from the Essential set, but packages have been removed from the Essential set when the functionality moved to a different package. So depending on these packages just in case they stop being essential does way more harm than good."
