On different ways to combine trees

[Alexander Belchenko]

You have explained scmproj very close to its reality, thanks.
Actually, when I was started it, I wanted it to support several vcs 
systems by simple config definition. The rudiment support for this you 
can see in vcs.py module of that plugin.
I think starting from the scratch makes sense here, using CLI as API 
to different systems will help you to quickly make a working prototype 
of your idea.

AFAIR, you can specify revision -r-1 in externals and scmproj configs 
to tell those suystems you want always latest revision of some components.

For me, the biggest problems with scmproj were:
1) I didn't provide a way to override source URL for components while 
getting snapshotted project. So any change in locations of components 
are disastrous.
2) The good idea of bzr "one branch - one URL" was not so good for 
scmproj's snapshots (partly because of previous problem). I'd like to 
have bzr branch/pull with explicit revid to work directly with shared 
repository and don't require a real branch object.
3) I've tried to make plugin too universal from the start. But ended 
up with 2 re-writes, and had to reduce number of available features 
based on real working experience.
4) Separate set of commands sometimes is good, but even with 
bzr-externals you don't have proper GUI support, like combined 
status/diff/log over all trees.
5) Big number of components, even divided into subprojects are proved 
to be a bad thing for me. It's hard to work with.

In the end I was very impressed by git-subtrees idea. It solves a lot 
of the problem I had with scmproj in more simpler way.

If you have some specific questions about scmproj and why it is as it 
is now, I'll be glad to answer.

Alexander