Re: [GSoC][PATCH 13/13] submodule: port submodule subcommand 'foreach' from shell to C

On Mon, Jul 31, 2017 at 1:56 PM, Prathamesh Chavan [off-list ref] wrote:

This aims to make git-submodule foreach a builtin. This is the very
first step taken in this direction. Hence, 'foreach' is ported to
submodule--helper, and submodule--helper is called from git-submodule.sh.
The code is split up to have one function to obtain all the list of
submodules. This function acts as the front-end of git-submodule foreach
subcommand. It calls the function for_each_submodule_list, which basically
loops through the list and calls function fn, which in this case is
runcommand_in_submodule. This third function is a calling function that
takes care of running the command in that submodule, and recursively
perform the same when --recursive is flagged.

The first function module_foreach first parses the options present in
argv, and then with the help of module_list_compute, generates the list of
submodules present in the current working tree.

The second function for_each_submodule_list traverses through the
list, and calls function fn (which in case of submodule subcommand
foreach is runcommand_in_submodule) is called for each entry.

The third function runcommand_in_submodule, generates a submodule struct sub
for $name, value and then later prepends name=sub->name; and other
value assignment to the env argv_array structure of a child_process.
Also the <command> of submodule-foreach is push to args argv_array
structure and finally, using run_command the commands are executed
using a shell.

The third function also takes care of the recursive flag, by creating
a separate child_process structure and prepending "--super-prefix displaypath",
to the args argv_array structure. Other required arguments and the
input <command> of submodule-foreach is also appended to this argv_array.

Helped-by: Brandon Williams [off-list ref]
Mentored-by: Christian Couder [off-list ref]
Mentored-by: Stefan Beller [off-list ref]
Signed-off-by: Prathamesh Chavan <redacted>
---
In this new version, the following changes have been made:
* Comment style is improved in the function runcommand_in_submodule()

* Comment in added about why the variable "path" was exposed via args
  argv_array instead of exposing it via the env_array.

* This patch exposes the various variables when argc == 1 only, just
  for maintaining a faithful porting. You can also find discussion about
  the same at [1].

[1]: https://public-inbox.org/git/CAME+mvUSGAFbN5j-_hv7QpAS57hq4wgH+yZ7XJMPuyQN1gALaA@mail.gmail.com/

Ah right, maybe add a NEEDSWORK or have the commit message explain
this behavior.