GSoC Project Selected | Incremental Rewrite of git bisect

Hey everyone,

I am Pranit Bauva studying Mining Engineering at Indian Institute of Technology, Kharagpur. I have applied for Google Summer of Code 2016 under Git organization and my project[1], "Incremental Rewrite of git bisect has been selected under the guidance of mentors namely Christian Couder and Lars Schneider.

Overview of the project:

Git bisect is a frequently used command which helps the developers in finding the commit which introduced the regression. Some part of it is written in shell script. I intend to convert it to portable C code thus making them builtins. This will increase Git’s portability.

A word of thanks:

Firstly I would really like to thank everyone who was involved in planning GSoC for Git especially my mentors. Also thanking Eric Sunshine, SZEDER and Junio for patiently reviewing my micro-project and helping me through that. It was a really great experience. I had previously no clue about git bisect and have never used it mainly because I was never involved with maintaining big projects. Posting my idea to the mailing list (which initially contained a lot of mistakes) was extremely helpful. Thanks to Christian Couder, Matthieu Moy, Johannes Schindelin and Stefan Beller for providing useful comments. Experimenting by converting one function really helped me a lot to write the proposal. Thanks Roberto for making submitgit.

The subtle hints dropped were the most helpful. Thanks for explaining those when I could not pick up those hints in the first time.

Status of Micro-project: I had finalized v14[1] but recently Junio pointed out that the series requires ordering and restructuring so I will finish with that. I have my end semester exams going on so I will try to squeeze out some time in between and try to work on the patches.

Status of the function conversion: I had attempted to port a function 'check_term_format' from shell to C. The last version was v3[2]. In the newer version (there only exist a local copy as I have neither sent it in the mailing list nor I have pushed it on github) as one test is not exiting properly. The code written with confusing error handling and return statements which were mainly there to help me understand "What's happening and where is it happening?" As requested by Christian, I will still push these changes to my github fork[3]. Also the function I have written does not use the API of git as at that time I wasn't quite familiar with it. I am still not completely familiar with it but I guess that will take some time.

Status of learning about git plumbing commands:
I have learned about:
 - git-check-ref-format
 - git-rev-list
 - git-rev-parse

The one's left are:
 - git-symbolic-refs
 - git-show-branch
 - git-update-ref
 - git-for-each-ref

Status of Week 1 of my proposal: In my 1st week I was going to set up kcov to test the coverage of shell scripts as gcov does not cover them. kcov is a lot trickier than gcov which I hadn't realized it before. I tried to use it in a simple way but it just wasn't possible for me. So I dug further and found a patch[5] submitted by Dmitry Vyukov. The linux kernel recently started using kcov for their coverage and to also find bugs by using some fuzzy logic. Setting this up is well not a piece of cake at least for me. I tried reading his patch and wasn't quite able to digest it in the first read but then I didn't look into that further. I would really like if someone could look this up and recommend whether I should try and implement this or not in the first week. If let's say I try to implement it, then I probably think it is more than a week's job. I recollect Matthieu saying that Paul Tan had used this before. Could you please explain how he achieved this?

When will I officially start working? My end semester exams end on 29th April, 2016 and I will reach my home on 1st May, 2016. I will officially start working from 2nd May, 2016 and will complete reading up on plumbing commands and other API parts which seems a bit ambitious as for now.

Other remarks:
 - I can now finally use git-send-email when I reach home.
 - I will regularly (weekly) keep posting my progress on my blog[6]
which will be revived  as it has been a bit stale for some time now. I
will also send the text-only version to the mailing list as requested
by Christian.
 - The more I dived in, the more it started to realize that my time
line needs some restructuring which I guess can be determined by the
above paragraphs.
 - I will also work out on a time line and post it on my blog[6] and
send it to mentors.

[1]: https://docs.google.com/document/d/1stnDPA5Hs3u0a8sqoWZicTFpCz1wHP9bkifcKY13Ocw/edit?usp=sharing

[2]: http://thread.gmane.org/gmane.comp.version-control.git/291311

[3]: http://thread.gmane.org/gmane.comp.version-control.git/289599

[4]: https://github.com/pranitbauva1997/git

[5]: http://thread.gmane.org/gmane.linux.kernel/2126762

[6]: http://bauva.in