dh_installsystemd and Also= directive

[Niels Thykier]

Daniele Nicolodi:
> Hello,
> 
> please keep me in Cc, I'm not subscribed to the list.
> 
> I'm implementing user units support in dh_installsystemd. For doing so
> the code needs a bit of refactoring and thus I'm trying to understand
> how the tool is supposed to operate and adding some tests to check that
> nothing will break in the process.
> 
> dh_installsystemd needs to resolve Also= directives in service files to
> emit postrm blocks to disable all unit enabled at installation time. The
> code seems to try to support unit files that have Also= directives
> pointing to units defined in other packages, however, if one of those is
> encountered dh_installsystemd fails a bit later when it tries to read
> the unit file specified in the Also= directive and does not find it.
> 

Ack, note that the "late failure" is deliberate to present as many
issues to the user as possible (to keep the amount of "rinse and
repeat"-testing to a minimum).

> Because of this failure, I believe that no one relays on this
> functionality. I also don't think it is a good practice to have an unit
> have an Also= directive pointing to a unit defined in another package,
> it seems a recipe for unexpected results.
> 

I do not think it was ever intended to support units from other
packages.  And I agree, it looks like a recipe for disaster.

> Should this use case be supported?  Or should the half baked support be
> removed and error handling in dh_installsystemd improved a bit?
> 
> Thanks. Cheers,
> Dan
> 

I think this is mostly a question of documentation changes and possible
a tweak of the error message?

Thanks,
~Niels