Adding this in general doesn't thrill me because recursive submodules aren't captured in vcs export --exact. I know there's a specific case this is checking and that the PR is still in draft but I wanted to express apprehension before I forgot about it.

Adding this in general doesn't thrill me because recursive submodules aren't captured in vcs export --exact.

That's a good point. I think we should make it so that it can.

Right now, bloom is fetching submodules so I think it's reasonable to have that behavior here too.

After an upstream patch to python_orocos_kdl, I don't think we need this feature any longer. I'll plan to close this PR unless there's consensus to move forward with it.

Right now, bloom is fetching submodules so I think it's reasonable to have that behavior here too.

I don't think that's an unreasonable position. I would be happier removing submodule support from bloom than adding it here.

Its addition in bloom was not intentional as much as it was enabled by features in vcstool and then unblocked to "make a thing work" but it's worth thinking about whether it's a supportable pattern.

Given the last couple of comments, I'm going to close this out since I don't think we'll move forward here. Feel free to reopen if I'm wrong.