Fwd: My Introduction and a Doubt

Hey everybody!

I'd love to use this email to introduce myself to the community and ask for help.

I'm Nirmal Khedkar, student from India. I love making end user applications, and in this FOSS world, there simply aren't many as big and impactful as Git. I'd love to contribute Git for GSoC 2020 as well as for long-term.

Now the doubt: I'm trying to wrap up the issue mentioned here (https://github.com/gitgitgadget/git/issues/486) : basically allowing git bisect to work from subdirectories. I do consider myself okay in C but I'm still kind-of stuck here: hence emailing this on the mailing list.

 When you do "git bisect" in a subdirectory, an error "You need to run
this command from the toplevel of the working tree." is raised. The
error is raised in "git-sh-setup.sh" and the command begins execution
in "bisect--helper.c", but I cant understand how the error appears.
Additionally I'd love to know how the C files linkwith the numerous
shell scripts within Git.

I've searched all I could within the Git project, but if there's any existing documentation on this, please let me know.

Thanks in advance! Nirmal Khedkar