Subject: Re: [GSOC/RFC] GSoC Proposal Draft | Git Beginner

From: Sidhant Sharma <[email-masked]>
Date: Tue, 22 Mar 2016 15:13:07 +0530

Updated examples with better description for force push and reset HEAD, as
suggested by Lars [11].

Thanks and regards,
Sidhant Sharma

[11]: http://thread.gmane.org/gmane.comp.version-control.git/289365/focus=289495

---

Implement a beginner mode for Git.

Abstract

Git is a very powerful version control system, with an array of features
that lend the user with great capabilities. But it often so happens that some
beginners are overwhelmed by its complexity and are unable to fully understand
and thus, utilize Git. Moreover, often beginners do not fully understand
the command they are using and end up making destructive (and occasionally,
irreversible) changes to the repository.

The beginner mode will assist such  users in using Git by warning them
before making possibly destructive changes. It will also display tips and
short snippets of documentation for better understanding the Git model.

Google summer of code Idea suggested here:
http://git.github.io/SoC-2016-Ideas/#git-beginner

About Me

Name : Sidhant Sharma
Email [1] : Sidhant.Sharma1208 <at> gmail.com
Email [2] : Tigerkid001 <at>  gmail.com
College : Delhi Technological University
Studying : Software Engineering
IRC : tk001 (or _tk_)
Phone : 91-9990-606-081
Country : India
Interests : Computers, Books, Photography
Github : Tigerkid001
LinkedIn : https://in.linkedin.com/in/sidhantsharma12

Technical Experience

Authored several Mozilla Firefox and Google Chrome extensions:
Firefox: Owl [1], Blink [2], Spoiler Jedi [3]
Chrome: Blink [4]

Developed a robust Plugin framework for Android [5] for a startup.
Learning Linux kernel programming via the Eudyptula Challenge [6]
(currently level 6).
Developed natural language processor for sarcasm detection [7] in tweets.
Developed hand gesture detection module [8] as a college minor project.
Active Firefox Add-ons Editor at AMO [9].
Currently working on a restaurant image classification project as second college
minor project.

Why I chose Git

I have been using Git for about two years now, and it has become an
indispensable daily-use tool for me. Getting a chance to participate in GSoC
for the first time under Git is very exciting. It will give me an opportunity
to intimately know the system and a chance to help in making it better and more
powerful.

Proposal

Ideas Page: Git Beginner [10]

The following tasks summarize the project:

Implement a wrapper around Git

A wrapper is to be implemented around (currently called 'ggit'), which will
provide the following user interface:
`ggit <git-command> <options>`
For example, `ggit add --all`
The wrapper will assess the arguments passed to it, and if they are detected to
be safe, it will simply pass them through to 'git'. This approach is favorable
as the existing users of git will not be affected by the wrapper.

Warning for potentially destructive commands

For every command that is entered, the wrapper will assess the subcommand and
its options. In that, it will first check if the subcommand (eg. add,
commit, rebase) is present in a list of predefined 'potentially destructive'
commands. This can be done by searching through a radix tree for the subcommand.
If found, then the arguments to the subcommand will be checked for specific
flags. The graylisted flags for the destructive commands will be stored as an
array of regular expressions, and the current command's arguments will be
checked against them. If matches are found, a warning is displayed. 'ggit'
for the warning would be
"You are about to do X, which will permanently destroy Y. Are you sure you wish
to continue? [Y/n] "
If the user enters Y[es], the command will be executed as is (by passing it
unaltered to git). In the case of Y[es], 'ggit' will also give tips for undoing
the changes made by this command (by referring the user to correct commands and
reflog),  if the command can be undone. In case the command cannot be undone,
'ggit' will display an additional line in the warning like
"The changes made by this command cannot be undone. Please proceed cautiously".
In the case of n[o], 'ggit' will exit without executing the command.

Currently, the list consists of commands like:

$ git rebase
$ git reset --hard
$ git clean -f
$ git gc --prune=now --aggressive
$ git push -f <branch>
$ git push remote [+/:]<branch>
$ git branch -D

The list will be updated after some more discussion on the list.

Usage tips and documentation

The wrapper will also be responsible for showing a short description of every
command that is entered through 'ggit'. This shall be done for every command
unconditionally. The description will be derived from the actual documentation,
but  will primarily aim to help the beginner understand the Git workflow and the
Git model.

A few examples to illustrate the working of the wrapper are:

$ ggit add --all
Staging all changes and untracked files. Use ` [g]git commit` to commit the
changes.

$ ggit commit -m “Second commit”
Committing staged changes…
[master 0be3142] Second commit
 4 files changed, 6 insertions(+), 2 deletions(-)

$ ggit reset HEAD~1 --hard
Resetting HEAD to 1 previous commit.
[WARNING] You are about to hard reset the current HEAD (master) by 1 commit.
This will take you back to commit b16aae3, and discard all changes make
thereafter. If you want to reset but also want to retain the changes made since,
use --soft instead of --hard.
Are you sure you want to continue? [Y/n] y
Resetting HEAD to b16aae3…
You can undo this action by resetting the HEAD to last commit you were on, that
is:
`$ ggit reset HEAD 0be3142`
In general, you can see the previous positions of HEAD by running `git reflog`.
HEAD is now at b16aae3 First commit

$ ggit push --force origin master
Pushing changes to origin/master
[WARNING] You are about to purge commits from the http://example.com/repo master
branch and overwrite its history to match yours.

State right now:
        o---o---o---A---B  master on http://example.com/repo
             \
              X---Y---Z  your master

State if you continue:
        o---o---o---X---Y---Z  master on http://example.com/repo and your master

Commit A and B will be gone. If other people have worked on top of A or B then
they won't be able to merge their changes easily.

Are you sure you want to continue? [Y/n] n
Aborting push to origin/master

Timeline

Community Bonding Period

Week 1 : Discuss the flow of course with the mentor. Discuss adequate data
structures and search techniques to be used.

Week 2-3 : Discuss over an extensive list of commands that should be classified
as destructive. Discuss appropriate short descriptions for commands. Submit
sample patches for the same for comments and review.

Week 4 : Discuss code structure, tests, optimization for least overhead and
other details.

Coding Starts

Week 1-2 : Submit code for a basic wrapper that will warn for a subset of the
potentially destructive command, and continue if the command is safe.
and this is stored as per to provide backward compatibility.

Week 3-5 : Extend the wrapper to warn for more commands in the list, along with
proper instructions for undoing them. Write tests for the commands supported so
far.

Mid Term Evaluation

Week 6-7 : Complete support for all graylisted commands with tests.

Week 8-12: Add beginner-friendly documentation snippets to various git commands.

Week 13 : Final cleanup, final touches suggested by mentors and community.

Pens Down Date
Submission of Code to GSOC

[1]: https://addons.mozilla.org/en-US/firefox/addon/owl/
[2]:  https://addons.mozilla.org/en-US/firefox/addon/blink/
[3]: https://addons.mozilla.org/en-US/firefox/addon/spoiler-jedi/
[4]: https://chrome.google.com/webstore/detail/blink-new-tab/kakaolkgegapcgdjdmlmcigejblohpkh/
[5]: https://github.com/TigerKid001/flubbr
[6]: http://eudyptula-challenge.org/
[7]: https://github.com/TigerKid001/Perry
[8]: https://github.com/TigerKid001/Dex
[9]: https://addons.mozilla.org/en-US/firefox/
[10]: http://git.github.io/SoC-2016-Ideas/#git-beginner