Re: [GSoC] My Git Dev Blog – Week 8

From: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Date: Jul 13, 2021, 08:18 UTC
Message-ID: <f5b12a75-bdaf-fe5c-ffc2-7b4c8cdfddd6@gmail.com>
In-Reply-To: <CD6968A1-179D-4B77-91C1-4EECB1B69951@gmail.com>

Hi Atharva,

On 11/07/21 4:48 pm, Atharva Raykar wrote:

Show 6 quoted lines

> Here's my weekly update:
> https://atharvaraykar.me/gitnotes/week8
> 
> I am currently blocked by trying to pass a super-prefix parameter
> to another command, when calling it from within C.
>

 From the blog:

> When queried by the get_super_prefix() function, the answer is (null).
> This boggles my mind to no end (see update). The implementation is basically
> the same getenv() call?

Good to see that you were able to identify the reason yourself.

> I am not sure how to tell Git that the environment variable has in fact
> been modified, and that it needs to be reinitialized. Maybe I am going
> about this whole thing wrong?

I get the same feeling too. I took a brief look at how the issue could be fixed and it seems to me that you exploring to set super-prefix might not lead us to the solution. Alternatively, you could explore how other sub-commands handle recursing into submodules. To me it looks like they handle it by spawning a sub-process is likely the easiest approach for achieving recursion. That would solve the super-prefix problem as you have observed.

Unfortunately, there's not yet proper support for handling recursion of submodules which calls for working with the data of multiple Git repositories in the same Git process. There was an effort[1] few years ago to make working with other Git repositories simpler without having to spawn a sub-process. The state of the effort is unclear to me. As far as I know, it has been stalled. I hope others could provide more details about it.

So, you could try the approach of spawning of sub-process for now. In case there's a better approach than spawning sub-process others might be able to point during review. In the meanwhile, I'll try to take a better look later and see if I could find anything.

[1]: https://public-inbox.org/git/20180205235508.216277-1-sbeller@google.com/

-- 
Sivaraam