Re: [GSoC] [PATCH 3/3] submodule--helper: introduce add-clone subcommand

[Atharva Raykar <raykar.ath@gmail.com>]

On 08-Jul-2021, at 01:27, Junio C Hamano <gitster@pobox.com> wrote:
> 
> Atharva Raykar <raykar.ath@gmail.com> writes:
> 
>> 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.
> 
> Makes sense.
> 
>> The 'die' that is used in git-submodule.sh is not the same as the
>> 'die()' in C--the latter prefixes with 'fatal:' and exits with an error
>> code of 128, while the shell die exits with code 1.
>> 
>> Introduce a custom die routine, that can be used by converted
>> subcommands to emulate the shell 'die'.
> 
> I suspect that installing this with set_die_routine() might be going
> too far.  If some of the lower-level helper routines we call from
> here have to die (e.g. our call results in xmalloc() getting called
> and we run out of memory), die() called there will also end up
> calling our submodule_die(), not just new calls to die() you are
> adding in this patch.  Calling submodule_die() directly from the
> code you convert from the scripted version where we used to call die
> of the scripted version would be fine, though.
> 
> I suspect that it would be OK to use the standard die() instead,
> with the minimum adjustment as needed, namely, we may have to
> 
> * Adjust the messages the scripted version of the caller gave to
>   the scripted version of die, if needed (e.g. if the scripted
>   version added "fatal:" prefix itself to compensate for the lack
>   of it in the scripted "die", we can drop the prefix and call the
>   standard die());
> 
> * Adjust the tests if they care about the differences between
>   exiting 128 and 1.

Okay, will do. The latter will not affect the tests, but the inclusion
of a 'fatal:' prefix will require me to adjust one test that checks for
the error message.