Service users and backwards compatibility

[Bertrand Delacretaz <bd...@apache.org>]

Hi,

We should now be ready to remove admin sessions wherever possible in
our code and test the results, the SLING-5449 repository
initialization language is not completely finished but can be used in
tests already.

What's our plan about backwards compatibility when we introduce service users?
People will need to create service users for modules that didn't use
them before but start doing so.

A simple way to create those, that works in all environments, is to
implement a RepositoryInitializer like [1] does.

Are people ok with just pointing to that example (which is used in our
integration tests so guaranteed to work) or do we need more than that?

-Bertrand

[1] https://github.com/apache/sling/blob/trunk/launchpad/test-services/src/main/java/org/apache/sling/launchpad/testservices/repository/SystemUsersInitializer.java

Uses https://github.com/apache/sling/blob/trunk/launchpad/test-services/src/main/resources/repoinit.txt
which can contain any statements supported by the
bundles/commons/repoinit language. Which needs to be documented, for
now examples are in tests there.