When working with submodules, nearly anytime after checking out a different state of the projects, that has submodules changed you'd run "git submodule update" with a current version of Git.
There are two problems with this approach: * The "submodule update" command is dangerous as it doesn't check for work that may be lost in the submodule (e.g. a dangling commit). * you may forget to run the command as checkout is supposed to do all the work for you. Integrate updating the submodules into git checkout, with the same safety promises that git-checkout has, i.e. not throw away data unless asked to. This is done by first checking if the submodule is at the same sha1 as it is recorded in the superproject. If there are changes we stop proceeding the checkout just like it is when checking out a file that has local changes. The integration happens in the code that is also used in other commands such that it will be easier in the future to make other commands aware of submodule. This also solves d/f conflicts in case you replace a file/directory with a submodule or vice versa. The patches are still a bit rough, but the overall series seems promising enough to me that I want to put it out here. Any review, specifically on the design level welcome! Thanks, Stefan Stefan Beller (16): submodule.h: add extern keyword to functions, break line before 80 submodule: modernize ok_to_remove_submodule to use argv_array submodule: use absolute path for computing relative path connecting update submodules: add is_submodule_populated update submodules: add submodule config parsing update submodules: add a config option to determine if submodules are updated update submodules: introduce submodule_is_interesting update submodules: add depopulate_submodule update submodules: add scheduling to update submodules update submodules: is_submodule_checkout_safe teach unpack_trees() to remove submodule contents entry: write_entry to write populate submodules submodule: teach unpack_trees() to update submodules checkout: recurse into submodules if asked to completion: add '--recurse-submodules' to checkout checkout: add config option to recurse into submodules by default Documentation/config.txt | 6 + Documentation/git-checkout.txt | 8 + builtin/checkout.c | 31 ++- cache.h | 2 + contrib/completion/git-completion.bash | 2 +- entry.c | 17 +- submodule-config.c | 22 +++ submodule-config.h | 17 +- submodule.c | 246 +++++++++++++++++++++-- submodule.h | 77 +++++--- t/lib-submodule-update.sh | 10 +- t/t2013-checkout-submodule.sh | 344 ++++++++++++++++++++++++++++++++- t/t9902-completion.sh | 1 + unpack-trees.c | 103 ++++++++-- unpack-trees.h | 1 + wrapper.c | 4 + 16 files changed, 806 insertions(+), 85 deletions(-) -- 2.10.1.469.g00a8914