Feedback on Ubuntu-specific debian/rules for building sysvinit

[Olivier Gayot]

Dear Debian maintainers of sysvinit,

A few years back, we decided for Ubuntu to disable the build of sysvinit 
binary packages except for sysvinit-utils which is marked [essential].

To achieve this, we added in debian/rules a bunch of ifeq/ifneq 
statements in override_dh_* rules disabling some instructions if we are 
building on Ubuntu [1]. As an example, we want to disable the following 
instructions if we are not building sysvinit-core or bootlogd:

dh_installchangelogs -psysvinit-core doc/Changelog
dh_installchangelogs -pbootlogd

We used to manage this Ubuntu delta internally and would rebase on top 
of Debian when new releases would come out.

However, since the move of some scripts from lsb-base to sysvinit-utils, 
there is now some Ubuntu-specific code in Debian d/rules [2]:

```
derives_from_ubuntu := $(shell (dpkg-vendor --derives-from Ubuntu && 
echo "yes") || echo "no")
```
```
ifeq ($(derives_from_ubuntu),yes)
ifneq (,$(findstring sysvinit-utils, $(shell dh_listpackages)))

	cp -p debian/src/lsb-base/init-functions.d/50-ubuntu-logging \

		debian/sysvinit-utils/lib/lsb/init-functions.d/

endif
endif
```

It feels counterproductive for Debian and for Ubuntu that our 
Ubuntu-specific sysvinit configuration is partially managed in Debian 
and partially in Ubuntu. So I would like to get your honest opinion on 
what you think would be the best approach going forward:

Option 1: Consolidating Ubuntu-specific configuration in Debian
---------------------------------------------------------------
We would move our Ubuntu-specific configuration in Debian. The result 
would make it much easier for Ubuntu to keep up with Debian (no need to 
rebase ; we can go back to syncing). Sadly, it will also add a little 
bit of gratuitous code on Debian's d/rules but we can work on making 
itless intrusive though. I believe there are more than one way to 
achieve this:
   * Add a few more ifeq/ifneq statements leaning on 
$(derives_from_ubuntu) which is already defined. This would basically 
reflect what we have currently in Ubuntu [1]
   * Add a few more ifeq/ifneq statements disabling some instructions 
based on the output of $(findstring <package>, $(shell dh_listpackages). 
I haven't tested it yet but I think it can be a cleaner way to honor the 
DH_OPTIONS without being too specific to Ubuntu.

Option 2: Continuing partial management in Ubuntu and Debian
------------------------------------------------------------
we continue having the Ubuntu delta partially managed in Ubuntu and in 
Debian. In my opinion, this is the least viable approach.

Option 3: Removing Ubuntu-specific code from sysvinit in Debian
----------------------------------------------------------------
We would basically drop the Ubuntu-specific stuff from sysvinit in 
Debian. We would manage our delta entirely in Ubuntu.

Your feedback would be very appreciated.

Thank you for the good work you put in Debian!

Best regards,
Olivier

[1] 
https://git.launchpad.net/~ogayot/ubuntu/+source/sysvinit/commit/?h=lp2007421/logical/3.05-7ubuntu2&id=b8097241efd7d465457eb9b6a474d749eaf3a540
[2] 
https://salsa.debian.org/debian/sysvinit/-/blob/a6a63fb900872c8f6d4e54e1e97fc6f7fffa94a3/debian/rules