Re: [RFC PATCH 00/16] Checkout aware of Submodules!

> 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(-)
>