Re: [PATCH v3] [GSoC] submodule--helper: introduce add-clone subcommand

> 
> Let's add a new "add-clone" subcommand to `git submodule--helper` with
> the goal of converting part of the shell code in git-submodule.sh
> related to `git submodule add` into C code. This new subcommand clones
> the repository that is to be added, and checks out to the appropriate
> branch.
> 
> This is meant to be a faithful conversion that leaves the behaviour of
> 'submodule add' unchanged. The only minor change is that if a submodule name has
> been supplied with a name that clashes with a local submodule, the message shown
> to the user ("A git directory for 'foo' is found locally...") is prepended with
> "error" for clarity.
> 
> This is part of a series of changes that will result in all of 'submodule add'
> being converted to C.
> 
> Signed-off-by: Atharva Raykar <raykar.ath@gmail.com>
> Mentored-by: Christian Couder <christian.couder@gmail.com>
> Mentored-by: Shourya Shukla <shouryashukla.oo@gmail.com>
> Based-on-patch-by: Shourya Shukla <shouryashukla.oo@gmail.com>
> Based-on-patch-by: Prathamesh Chavan <pc44800@gmail.com>
> ---
> 
> Changes since v2:
> * Remove printf debug statement that was accidentally inserted into the final
>   patch
> * Rename 'struct add_data info' to the more descriptive
>   'struct add_data add_data'
> * Remove unnecessary variables while parsing flags, and insert into the struct
>   members directly
> * Eliminate extra heap allocation via 'xstrndup()' in parse_token()
>   (I learnt this trick from Junio's comment on Shourya's v2 review of a similar
>   patch :^) )