Git Sandbox

Overview

Git is a practical thing. Maybe that's the reason why it's at times difficult to understand its formal documentation.

To find my way around a tricky Git use case, I don't rely solely on the docs. I have a quick glance at the docs to get a general idea, and then try that case in sandbox environment right away.

It's not always easy to create a multi-user Git sandbox environment manually, it takes quite an effort each time. Also in course of our experiments we often want to delete it all and start over, which adds a bit of pain.

Thus, step by step, Git Sandbox was born.

What's Git Sandbox?

Git Sandbox is a tool, which allows you to conduct Git experiments acting as several developers at once, do it fast and with minimal effort. The idea behind it is:

If you don't know how Git will behave in a particular tricky situation, go try it in a sandbox NOW.

Don't put it off, don't try to work around it by avoiding aspects you don't know well. In other words — just go try it. It won't bite, it'll take you just a few minutes of learning, but you'll gain solid knowledge and confidence which will be with you forever.

Setup

Download PS1 and Sandbox into an empty directory, do a chmod +x Sandbox, run ./Sandbox setup. Then follow the on-screen help. A complete example follows.

Example: Simulating a merge conflict

Create an empty directory and step into it:
```
$ mkdir git-xperiment
$ cd git-xperiment
```

Download the sandbox scripts, do the setup:

$ curl https://raw.githubusercontent.com/dadooda/git-sandbox/master/{PS1,Sandbox} -OO
$ chmod +x Sandbox
$ ./Sandbox setup
$ . PS1

Now that everything is ready, start playing with Git. Initialize the repo:
```
git-xperiment$ ./Init
```

Acting as developer Alice, start writing a poem. Notice how shell prompt changes as you step in and out developers' working copies:

git-xperiment$ ./Clone alice
git-xperiment$ cd alice
alice[]$ echo "The poem" > poem.txt
alice[]$ git add . && git commit -a -m "Update" && git push origin master

Connect one more developer, Bob. Let him add a line:

alice[master]$ cd ..
git-xperiment$ ./Clone bob
git-xperiment$ cd bob
bob[master]$ echo "Mary had a little lamb" >> poem.txt
bob[master]$ git add . && git commit -a -m "Update" && git push origin master

Back in Alice's working copy, add a line, commit, then fetch and merge:

bob[master]$ cd ../alice
alice[master]$ echo "Mary had a little ham" >> poem.txt
alice[master]$ git add . && git commit -a -m "Update" && git push origin master
error: failed to push some refs to 'git-xperiment/.repo.git'
hint: Updates were rejected because the tip of your current branch is behind
...

alice[master]$ git fetch
alice[master]$ git merge origin/master
Auto-merging poem.txt
CONFLICT (content): Merge conflict in poem.txt
Automatic merge failed; fix conflicts and then commit the result.

The conflict! That's what we wanted, and we got it. Proceed further to your liking.

Cheers!

Feedback of any kind is highly appreciated.