[arch-general] changelogs (was Re: postgresql 9.3 -> 9.4)

[Lukas Fleischer]

On Thu, 29 Jan 2015 at 17:06:43, Georg Altmann wrote:
> [...]
> On 29.01.2015 14:22, Bardur Arantsson wrote:
> > If the problem here is that it would be a chore to do this for 
> > maintainers for every X.Y -> X.(Y+1) upgrade, then maybe Arch 
> > package descriptions could grow a field or flag to handle such 
> > things semi-automatically? Maybe something as simple as "if the 
> > version number is about to change in *this way*, then warn loudly 
> > using *this message*".
> 
> Wouldn't that be a sensible way? The increased overhead for the
> maintainer would be to tick a flag in addition to the version bump.
> In the case of postgresql this would be a as simple as
> 
> if (oldMajor < newMajor ||
>   ((oldMajor == newMajor) && (oldMinor < newMinor)) {
>   printUpgradeWarning();
> }
> 
> Of course the condition would have to be serialized in the package
> meta-data some way. I have only very limited knowledge on the pacman
> internals. Maybe someone can come up with an estimate how big the
> effort would be to implement this.
> [...]

It isn't that easy. You cannot simply tick a flag, you need to maintain
a variable that keeps track of the last version that caused a warning.
Otherwise, there's no way to warn a user who upgrades straight from
1.0.0 to 2.1.0 when there were intermediate releases 1.1.0 and 2.0.0 and
some change between 1.1.0 and 2.0.0 that is worth a warning. And as a
matter of fact, that is what we already do in a lot of packages. You can
have a look at the install scriptlets of btrfs-progs, cups, dhcp,
dmraid, dovecot, ebtables, intel-ucode, linux, lirc, lvm2, mariadb,
nginx, openvpn, systemd, varnish, just to get an idea of what it looks
like. As I mentioned before, adding a similar check to PostgreSQL might
be a good idea but I, as a non-PostgreSQL user, cannot judge whether
that works and is worthwhile.