I realize you can set the depth of a submodule manually when updating it, see here, but is it possible to set that automatically, say as an option in the gitconfig? This way I could set it so when updating a submodule it only ever brings down a revision history of depth 2?
No, it isn't possible (for now, mid-2014) through git config
.
You could define an alias or a special script to add that parameters, but you can set depth
natively with git alone.