factory/release/stabilize/etc... branches should all be independent.  branching from the same version shouldn't be a problem.

what problems are you referring to ?  those should really be fixed if we have code that e.g. there will only ever be one branch associated with "11512".

Bernie weighed in on the other bug.
We have seen issues with change listings between versions.
I have also seen build artifacts do strange things.

The last time I made this mistake, I was relatively new.  Those more experienced that I coached me how to fix it by cherry-picking my (duplicated) branch changes into a non-duplicated branch.

Recently, there was a race between two projects.  Each of us created a branch within the same hour from the same branch point.

factory-octopus-11512.B shows a strange version history.  Since it was an official octopus factory branch, we moved atlas to stabilize-atlas-11512.6.B.  It seems that there is still some strange behavior there that I don't think is correct or expected.

Right now I plan on implementing this check in the strictest way possible: one branch per version. We can always relax the constraint later if we deem it not a problem.

Maybe a dumb question, but: dgarrett@ how do we avoid buildspec conflicts right now, if at all? If I have factory-1234.B and stabilize-1234.B, what prevents us from generating 1234.2.0.xml twice?

The code that creates the buildspecs looks for existing files, but exactly what it does, I'm not sure. You probably shouldn't expect it to do the right thing.