Bug#623249: libtango7 has circular Depends on tango-common

[Bill Allombert]

On Tue, Apr 19, 2011 at 01:55:26PM +0200, Picca Frédéric-Emmanuel wrote:
> Hello Bill,
> 
> I understand the problem and I will put here my proposition:
> 
> the Tango control system [1] is a distributed system based on CORBA.
> the unit cell of the system is called a "Device". Thoses devices (executable) are
> linked with the libtango7 library.
> To work a device must contact a daemon running somewhere on the internet
> this daemon is called the Database (the tango-db package).
> Then a configure file /etc/tangorc must be configure and contain
> the host and the port where is running the Database.
> 
> So If you want to execute a Device it must be register into the
> Database. That's why I created this tango-common package which take care of
> this config file creation.
> 
> So to be usable a program linked with libtango7 must also have this configure file
> set-up.
> 
> Now the init script of the Databse located in tango-db use an executable called
> tango_admin which IS linked with the libtango. I put it in tango-common and 
> this caused the circular dependency.

Why not put tango_admin in tango-db then ?
An alternative is to have all the packages using libtango7 to depend on tango-common.
This can be arranged via shlibs file.

> Now I propose to split tango-common (config + tango_admin) into 2 new packages
> tango-common (config) and libtango-tools (tango_admin)
> 
> that way I will have
> 
> libtango7 :Depends: tango-common
> libtango-tools :Depends: libtango7
> 
> Is it ok for you

It is fine with me. I am unfamiliar with libtango to have an opinion with this arrangement.

> If yes, I would like your advice for the transition, as tango_admin will be changed from one package
> to the other, It can cause conflict during upgrade.
> So is it sufficient to add
> 
> libtango-tools :Depends: libtango7 Replace: tango-common << (7.2.6+dfsg-1) Breaks: tango-common (<< 7.2.6+dfsg-1)
> libtango-common : Suggest: libtango-tools (>> 7.2.6+dfsg-1)

I do not think libtango-tools needs to Breaks: tango-common, but outside that it looks good.

Cheers,
Bill.