Initscript migration to systemd: triggerun called on downgrade

[Petr Pisar]

On 2011-09-01, Bill Nottingham <notting at redhat.com> wrote:
> Petr Pisar (ppisar at redhat.com) said: 
>> I'm migrating quota_nld service (provided by quota_nld subpackage of
>> quota spec) to systemd.
>> 
>> Offical howto <https://fedoraproject.org/wiki/Packaging:ScriptletSnippets#Packages_migrating_to_a_systemd_unit_file_from_a_SysV_initscript> recommends:
>> 
>> %triggerun -- httpd < 1.0-2
>> # Save the current service runlevel info
>> [...]
>> 
>> where `httpd < 1.0-2' are httpd packages older then 1.0-2 under
>> uninstallation and `1.0-2' is first httpd version with systemd support.
>> 
>> I modifed quota accoding this how-to, build a package (everything
>> locally) and I play with upgrades/downgrades between current F17 version
>> and this new one.
>> 
>> Everything works except the triggerun script is called even if doing
>> downgrade. Is it intentional and I do not understand triggers, or is it
>> a bug in RPM?
>
> The above triggerun would be called on any uninstallation of httpd less
> than 1.0-2, whether you're upgrading or downgrading.
>
And that's the point. If only httpd-1.0-2 is installed and you do
downgrade to httpd-1.0-1, then the triggerun will be executed which
is what I do not expect because no httpd less then 1.0-2 can be
uninstalled at the time.

BTW I've pushed quota-1:4.00-2 to F17. This is the version doing the
migration with triggerun. I print a message by the triggerun script, so
you see it's run even when downgrading to 1:4.00-1.

-- Petr