Git in GSoC 2014

I'm pleased to announce that Git has been accepted to this year's Google Summer of Code.

Student proposals will start coming in on March 22. In the meantime students will be reading our Ideas page[1] and enquiring about the program on the mailing list and on irc. There are many ways that existing git developers can help:

  - continue to add to and polish the Ideas page

  - interact with prospective students; besides responding to questions
    on the list, hanging around on #git and #git-devel on freenode is
    helpful

  - volunteer to mentor and/or rank student proposals. You can sign up
    at http://google-melange.com, and request to be added as a mentor
    for the git project.

We didn't discuss earlier whether we would have any specific requirements for students during the proposal period (e.g., having a patch accepted). It would be good to put together rules (or barring any specific requirements, guidelines to help students put together a good proposal) as soon as possible. Suggestions are welcome.

-Peff

[1] http://git.github.io/SoC-2014-Ideas.html

Hi.

I was just going to write an email about that I would like to participate in GSoC and contribute to Git project.

I don't have wide experience in C programming, but I could be start as a "janitor". I found several tasks here https://git.wiki.kernel.org/index.php/Janitor. For example "Refactor binary search functions". If this task is actual, I could be to start from it.

On 02/25/2014 04:41 PM, Jeff King wrote:

Cool! Thanks to Peff and Thomas and Vicent and whomever else was involved in getting our application done! For those who don't know, the application covers both Git core and libgit2.

Requiring students to submit a reasonable patch and follow up on review comments seems like it would be a good way to filter out non-serious students. (I hesitate to require that the patch be accepted because it can take quite a while for a patch to make it to master, despite of the student's efforts.)

Does anybody know whether other organizations have had good experience with criteria like that? Does it chase *all* the applicants away?

If we wanted to impose such a hurdle, then we would definitely have to make up a list of microprojects so that the students don't have to start from nothing. I imagine it shouldn't be too hard to find tiny projects estimated at 10-30 minutes of actual work, which should be plenty difficult for a student who also has to figure out how to check out the code, conform to our coding standards, run the unit tests, create a patch submission, etc.

If the reaction is positive to this idea then I volunteer to spend several hours tomorrow looking for microprojects, and I suggest other core developers do so as well. They should presumably be submitted as patches to the ideas repository [1].

What do you think?

Michael

[1] https://github.com/git/git.github.io

On Tue, Feb 25, 2014 at 06:15:28PM +0100, Michael Haggerty wrote:

Yeah, I think the early stages of "accepted" are somewhat vague. Probably "patch is in next" is a reasonable definition, but I do not think we even need to bind ourselves so strictly. Humans read, evaluate, and rank the proposals, so we can use our judgement about whether a patch looks promising.

If you haven't seen it, there is a guide written by mentors and admins from past years:

 http://en.flossmanuals.net/GSoCMentoring/

I did not see this particular subject covered, though I seem to recall it has come up on the mentor list in past years. I can't search the archive now, because they haven't re-added me for this year yet, but I'll do so once I have access.

I think I'm in favor. It seems like a minimal hurdle to overcome, and I think everybody is more than happy to coach new contributors through the process.

The hack-a-thon bug list I posted earlier has some potential points of interest, but I need to update it to reflect the work done that day (a lot of that is trickling in to me for initial comments, and then I'll direct them to the list, but I'm a bit behind on dealing with it).

Yes, though I think it makes sense to put them on a separate page. We should probably write up some notes for students, too: how to get in touch with us, what do we expect of them in the pre-proposal period, what would we expect in terms of communication and day-to-day workflow during the summer, etc.

-Peff

On 02/26/2014 11:23 AM, Jeff King wrote:

Agreed.

Since time is short, I already started on this. I wrote a first draft of an introduction for the students. I also started looking for microprojects. I started going through our source files alphabetically, and have already found six suggestions by "bundle.c", so I don't think there will be a problem finding enough tiny things to do.

See my branch on GitHub [1] or read the appended text below.

I've been looking for *really* tiny projects. Feedback is welcome about whether they are too trivial to be meaningful in distinguishing promising students from no-hopers. My feeling is that there is so much process involved in submitting a patch that it will take even a well-prepared student quite a while to make a change, no matter how trivial.

Also, how many suggested microprojects do you think we need (i.e., when can I stop :-) )?

Michael

[1] https://github.com/mhagger/git.github.io/tree/microprojects

--- layout: default title: SoC 2014 Applicant Microprojects ---

## Introduction

It is strongly recommended that students who want to apply to the Git project for the Summer of Code 2014 should submit a small code-related patch to the Git project as part of their application. Think of these microprojects as the "Hello, world" of getting involved with the Git project; the coding aspect of the change can be almost trivial, but to make the change the student has to become familiar with many of the practical aspects of working on the Git project:

* Downloading the source code: clone the repository using the
  [Git via Git](http://git-scm.com/downloads) instructions and read
  the `README` file.

* Build the source code: this is described in the file `INSTALL`.

* Glance over our coding guidelines in the file
  `Documentation/CodingGuidelines`.  We take things like proper code
  formatting very seriously.

* Read about the process for submitting patches to Git: this is
  described in `Documentation/SubmittingPatches`.

* Making the actual change.

* Run the test suite: this is described in the file `t/README`.  (If
  you have added new functionality, you should also add tests, but
  most microprojects will not add new functionality.)

* Commit your change.  Surprise: we use Git for that, so you will need
  to gain at least
  [a basic familiarity](http://git-scm.com/documentation) with using
  Git.  Make sure to write a good commit message that explains the
  reason for the change and any ramifications.  Remember to add a
  Signed-off-by line (see the coding guidelines for more information).

* Submit your change to the Git mailing list.  For this step you
  probably want to use the commands `git format-patch` and `git
  send-email`.

* Expect feedback, criticism, suggestions, etc. from the mailing list.

  *Respond to it!* and follow up with improved versions of your
  change.  Even for a trivial patch you shouldn't be surprised if it
  takes two or more iterations before your patch is accepted.  *This
  is the best part of the Git community; it is your chance to get
  personalized instruction from very experienced peers!*

The coding part of the microproject should be very small (say, 10-30 minutes). We don't require that your patch be accepted into master by the time of your formal application; we mostly want to see that you have a basic level of competence and especially the ability to interact with the other Git developers.

When you submit your patch, please mention that you plan to apply for the GSoC. This will ensure that we take special care not to overlook your application among the large pile of others.

## Ideas for microprojects

The following are just ideas. Any small code-related change would be suitable. Just remember to keep the change small! It is much better to finish a small but complete patch than to try something too ambitious and not get it done.

1.  Rewrite `git-compat-util.h:skip_prefix()` as a loop, so that it
    doesn't have to scan through the `prefix` string twice.

2.  Change `branch.c:install_branch_config()` to use `skip_prefix()`.

3.  In `branch.c:setup_tracking()`, figure out where the magic number
    `1024 - 7 - 7 - 1` comes from.  (Looking through the commit
    history might help.)  If the check involving the number is still
    necessary, document where the number comes from.  If the check is
    no longer necessary, explain why and delete the check.

4.  Rewrite `bulk-checkin.c:finish_bulk_checkin()` to use a `strbuf`
    for handling `packname`, and explain why this is useful.  Also
    check if the first argument of
    `pack-write.c:finish_tmp_packfile()` can be made const.

5.  Change `bundle.c:add_to_ref_list()` to use `hashcpy()`.  See if
    you can find other places where `hashcpy()` should be used instead
    of `memcpy()`.

6.  Change `bundle.c:add_to_ref_list()` to use `ALLOC_GROW()`.

On Wed, Feb 26, 2014 at 11:41:21AM +0100, Michael Haggerty wrote:

Thanks, the intro text looks great.

We probably need some intro text to go on the ideas page (that is what Google links to for prospective students) that points them to the microproject page.

I've merged and pushed out your branch (I'll work on getting push access for people, as there's no real reason for me to be an integration bottleneck with this stuff).

I really like the level of the projects below. It should be more about the process than the code, and I think you nailed that. I especially like the ones that require some digging in history.

The bug list I mentioned before is probably too heavyweight in that sense (they're more like 4-6 hour projects for somebody who isn't familiar with the code, plus submission headaches on top of that).

I think it depends on how quickly people do them. We can always add more if they run low (though 6 does not provide a huge buffer, so we may want a few more).

This is the only one that seemed like it might be _too_ trivial to me. The memcpy/hashcpy one is similarly trivial, but I like the add-on of "look for other places". I guess we could do that here, too.

-Peff

On Wed, Feb 26, 2014 at 11:41 AM, Michael Haggerty <mhagger@alum.mit.edu> wrote:

Note that for projects that are either libgit2-centric or mix Core Git and libgit2, it would be worth it to the students to submit a pull request on libgit2 (or ideally, on both projects, although that's going to be hard) in order to make themselves familiar with the code base.

On Wed, Feb 26, 2014 at 12:25:36PM +0100, Vicent Martí wrote:

Yeah, that makes sense. I think if students are thinking primarily about one of the libgit2 projects, they should focus on interacting with that community. Interacting with the mailing list is good, too, but I don't see a need to do a patch for both.

Can you come up with a short list of micro-projects for libgit2, similar to what Michael did for Git?

-Peff

Michael Haggerty <mhagger@alum.mit.edu> writes:

Very nice.

I'd suggest one step before all of the below.  

 * Here (http://thread.gmane.org/{TBD1,TBD2,TBD3...}) are a sample
   set of threads that show how a change and a patch to implement it
   is proposed by a developer X, the problem it attempts to solve,
   the design of the proposed solution and the implementation of
   that design are reviewed and discussed, and that after several
   iterations it resulted in inclusion to our codebase.  As a GSoC
   student, you will be playing the role of X and engaging in a
   similar discussion.  Get familar with the flow, need for clarity
   on both sides (i.e. you need to clearly defend your design, and
   need to ask clarifications when questions/suggestions you are
   offered are not clear enough), the pace at which the discussion
   takes place, and the general tone of the discussion, to learn
   what is expected of you.

That would help the later step, namely:

On 02/26/2014 08:48 PM, Junio C Hamano wrote:

Sounds good. I suggest we make your blob a paragraph before the list of bullet points rather than part of the list. Please suggest some "TBD*" then I'll add it to the text. Would we also fill in "X" with the name of the actual student involved in the conversation that is pointed to?

Michael

Michael Haggerty <mhagger@alum.mit.edu> writes:

I was not thinking about using a student thread (I do not remember having a good on-list interaction with past GSoC students).

How about using this one from our recent past:

    http://thread.gmane.org/gmane.comp.version-control.git/239068

which has the following good points to be used as an example.  It:

 - involved multiple cycles and multiple reviewers;

 - showed good response to the comments from the original author;
   and most importantly

 - had everything related to the topic in one single neat thread.

On 02/27/2014 08:19 PM, Junio C Hamano wrote:

Change pushed.  Thanks Junio!

Michael

Michael Haggerty <mhagger@alum.mit.edu> writes:

Thank you for starting this.

Another point to add to the above three-point list is that it had an example of the original author defending (some of) the design choices he made and reviewers who initially raised questions and/or issues agreeing with that choice after the thinking was clearly explained.

Congrats everyone who was successful in being picked for this year's GSoC.

Fabian with "Line options for git rebase --interactive" [0] Brian Gesiak with "Unify and Refactor Temporary File Handling" [1] Tanay Abhra with "Git configuration API improvements" [2]

I look forward to seeing how you go!

[0] https://www.google-melange.com/gsoc/project/details/google/gsoc2014/bafain/5750085036015616 [1] https://www.google-melange.com/gsoc/project/details/google/gsoc2014/modocache/5639274879778816 [2] https://www.google-melange.com/gsoc/project/details/google/gsoc2014/tanayabh/5766466041282560

Regards,

Andrew Ardill

Thank you!

I'm very excited to be participating in this year's GSoC. Google recommends that students use the next few weeks to get to know their mentors, read documentation, and get up to speed to begin working on their projects. Students have also received instructions on submitting tax forms and other paperwork.

Aside from filing all the requisite paperwork, I plan on reading through the extensive set of patches on lock files Michael Haggerty submitted after my initial proposal. I also plan on consulting with my mentor, Jeff King, on some good first steps.

By the way, my name is Brian Gesiak. I'm a research student at the University of Tokyo, specializing in parallel and distributed computing. If you have any questions regarding my project, "Unify and Refactor Temporary File Handling", please feel free to contact me via this mailing list, or privately via email. I'm also on GitHub[1] and Twitter[2].

[1] https://github.com/modocache [2] https://twitter.com/modocache

- Brian Gesiak

On Tue, Apr 22, 2014 at 10:06 AM, Andrew Ardill <andrew.ardill@gmail.com> wrote:

On Tue, Feb 25, 2014 at 10:41 PM, Jeff King <peff@peff.net> wrote:

One thing I noticed after tg/index-v4-format is both libgit2 and jgit do not seem to support index v4. So we could add "index v4 support on libgit2" to the idea page. It's a relatively small task though once you get a hang on index format.

On Wed, Feb 26, 2014 at 12:16 PM, Duy Nguyen <pclouds@gmail.com> wrote:

That sounds like a nice task for the Summer of Code too, specially with the current effort to make Index v4 more visible in Core Git.

I wonder if anybody from JGit would also be interested on mentoring for the equivalent task (index v4 on JGit). I've CC'ed Shawn Pearce.

On Wed, Feb 26, 2014 at 12:24:13PM +0100, Vicent Martí wrote:

Yeah, I'd agree. Want to write it up?

A project that added to both libgit2 and JGit would be cool, but I don't know if that is asking too much of the student (multiple languages and projects is going to increase the time spent on non-code friction).

-Peff

On Wed, Feb 26, 2014 at 3:30 AM, Jeff King <peff@peff.net> wrote:

I agree, its too much to ask from a single student to add it to both projects.

As far as JGit supporting index v4, I am holding my breath and waiting for index v5. We keep spinning through dircache versions with relatively little gain for each one, but a lot of complexity. As it was a prior version was sort of a disaster with the fixed length portion of records being either 62 or 64 bytes depending on a bit set per record. Yuck. I haven't been reading every message in the v4 topic but nothing impressed me as being worth my time to implement in JGit, other than to be compatible with a version of git-core that won't land in Debian stable for at least 2 more years.

On 2014-02-25 16.41, Jeff King wrote:

I'm not sure if this is the right way to propose mini projects, but in case the answer is not no, may I suggest one:

Motivation, the problem: Since commit c28facd216b501d41ca76f "cygwin: stop forcing core.filemode=false" Git under cygwin initializes repos with core.filemode = true under NTFS

This allows a smooth workflow, when e.g. *.sh files are pushed and pulled between Cygwin, Linux/Unix or Mac OS.

However when I visit such a repo under Mingw, then Mingw reads core.filemode =true, but is unable to detect whether the X-bit is set, and reads it as not set.

Therefore "git status" thinks that e.g. all *.sh files have lost the executable bit, abd reports them as changed.

Proposal: Under Mingw, keep trust_executable_bit always false, regardless what core.filemode says. Activate NO_TRUSTABLE_FILEMODE in config.mak.uname for Mingw (currently it is not used to anything)

Keep the logic in init-db.c to initialize core.filemode = false under Mingw 

Language: C
Difficulty: easy