Re: [GSoC][PATCH 04/13] submodule: port submodule subcommand 'status' from shell to C

On Tue, Aug 1, 2017 at 2:42 AM, Stefan Beller [off-list ref] wrote:

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

quoted

This aims to make git-submodule 'status' a built-in. Hence, the function
cmd_status() is ported from shell to C. This is done by introducing
three functions: module_status(), submodule_status() and print_status().

The function module_status() acts as the front-end of the subcommand.
It parses subcommand's options and then calls the function
module_list_compute() for computing the list of submodules. Then
this functions calls for_each_submodule_list() looping through the
list obtained.

Then for_each_submodule_list() calls submodule_status() for each of the
submodule in its list. The function submodule_status() is responsible
for generating the status each submodule it is called for, and
then calls print_status().

Finally, the function print_status() handles the printing of submodule's
status.

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:
* parameters passed to the function print_status() have been changed.
  Instead of passing char *sub_sha1, instead the object_id is being passed.

* Also, since the passed parameter displaypath's value isn't changed
  by the function, it is passed to the funcition as const char *displaypath
  instead of char *displaypath.

* the output type of the function handle_submodule_head_ref() is changed
  from strbuf to object_id, as we will use the object_id instead of the
  hex of sha1 being stored in a struct strbuf.

* diff_files_args is cleared after using it by passing it as args in the
  function cmd_diff_files.

* In the function status_submodule(), for checking if a submodule has merge
  conflicts, the patch currently checks if the value of any of the ce_flags
  is non-zero. Currently, I think the we aren't interested in a partiular flag,
  but I'm not sure on this.

* Debugging leftovers and suprious new-lines are removed.

* The confusion with displaypath being passed as te super-prefix in many
  of the ported subcommands may be a result of the fact that the
  function generating the displaypath: get_submodule_displaypath()
  uses the super-prefix as simply a path concatenated with the current
  submodule name to denote our current location.
  The function get_super_prefix() is declared in cache.h and defined in
  environment.c, but is majorly used in the builtin/submodule--helper.c
  and also in unpack-trees.c
  Also, for generating any submodule's displaypath, it would be important to
  have ".." passed to the submodule, and currently it is possible only via the
  super-prefix.
  This is also other instaces where the super-prefix contained ".." as well.
  One of such instance is Test 4 from t7406-submodule-update.sh
  Hence, maybe documenting the value of displaypath might a solution
  for the above problem.
  I'm just stating my views and would like to recieve your opinion on this
  matter.

Yes, I agree that the display path is not quite easily understood as it can be
ambiguous.  I am confused by this paragraph:
* does test 4 from 7406 fail here, or was it just the starting point
  of the discussion and it all works fine?

Sorry for misleading there. In the discussion earlier, Brandon mentioned that
displaypath's value may contain ".." as well.
To this, I replied pointing out one of the test which checks for the value of
displaypath.
In this test, ( Test 4 from t7406-submodule-update.sh), the value of displaypath
is being calculated via the submodule_init() function present in
submodule--helper.c
Here, I wanted to point out that, even in the case of this function,
the variable
displaypath is evaluated after receiving the value of "../super/" as
the value returned
by the function get_super_prefix().
Hence, to correct this confusion about the usage of super-prefix,
(which as pointed out by Brandon has been traditionally defined
as the path from the root of the superproject down to the root of
the submodule which further means that there should not ever be
any relative '..'s.), we may either have to get the value of super-prefix's
Documentation to accomodate this change, and to accept the way it is
used in submodule--helper and the current patch series, or else,
change the way it is being used in the various function, and used
another method for evaluation of displaypath.

Thanks,
Prathamesh Chavan