My daily GIT workflow

I haven't been posting anything that is iPhone development related for a long time. I am a bit busy with my full time .NET contract at the moment which means few time for Obj-C development. But a few weeks (or months?) ago, when I was much more involved in iPhone development I decided to move my SVN repository to Git. So far I am very happy about it and I would like to share with you my daily Git workflow and why I started to love it from day one!

Why Git?

Git is different than any CVS-based revision control system. It's a distributed revision control system which means that you can have version controlling capabilities (along with ability to share your code with your teammates) without a need for a central server. Every Git working folder is your local, full-fledged repository containing the whole code history which means that you no longer depend on a network access or a central server. What does it mean in practice? Let's see.

Git basics

Starting with git is very easy. I was using SVN before so I had to migrate my revision history to Git using git svn command. I found this tutorial helpful with one remark - instead of git-svn I had to type git svn because the first didn't work for me. To start from scratch and add existing project to Git I go to project folder and type the following:

git init
git add .
git commit -m "Initial commit"

From now on, all my source code is controlled by Git and my repository is stored in project's .git folder (locally!). I can check it by executing:

git log

which shows my code history. I also use gitx to see it in a nice Mac OSX GUI or use Git extensions if I am on Windows.

To see which files has changed during your last commit I type:

git status

To commit my changes I do the following:

git add .
git commit -m "Commit message"

or if I don't have any new files:

git commit -a -m "Commit message"

which will commit all modified files shown by git status.

To discard all the changes that I made in my working folder I type:

git reset --hard

which turns a working folder to a state from my last commit. If I need to discard my last commit I type:

git reset --hard HEAD~1

To discard only some of the files I can type:

git checkout -- file

Remote repositories

You can freely share your code with your teammates without a need for a central server and Git allows you to push & pull your changes between different computers. I prefer to have a central server, and for this purpose I have setup a Git bare repository on my webfaction account and I am so far very happy about it. To push my changes to remote I need to do the following:

git push origin master

To pull the changes from a server I do:

git pull origin master

Branching

The power of Git is in its branching. In fact Git encourages you to branch very often - it's a very cheap operation and merging of a branch is very easy. I do a branch for every feature, major issue, every release / hotfix and I also maintain master / develop branches as remote branches. It allows me to have a development not interrupted by a release process and also have a possibility to implement hotfixes on production release.

To start a branch I do the following:

git checkout -b feature1

When I am done with implementation of a feature I need to merge it into develop branch and after that I am safe to delete a feature branch:

git checkout develop
git merge feature1
git branch -d feature1

Git will always try to do a fast-forward merge here. If I need to preserve a history of my feature branch (to have a possibility to see which individual commits create a feature) I force Git not to do a fast-forward merge with a --no-ff option:

git merge --no-ff feature1

Release management with Git

When I am ready to release a new version I do a branch, update a version, do some minor fixes (if necessary) and then merge into master branch and tag:

git checkout -b release-1.0.0.0 develop
// update version
git commit -a -m "Updated version to 1.0.0.0"
// do some fixes if necessary
git commit -a -m "Fixes"
git checkout master
git merge --no-ff release-1.0.0.0
git tag v1.0.0.0

I also have a develop branch so I need to merge it into this branch as well and then I can safely remove a release branch:

git checkout develop
git merge --no-ff release-1.0.0.0
git branch -d release-1.0.0.0

Hotfixes (if something bad happened on production and I don't want to do a new release from develop) are created from master branch (which contains only production releases!):

git checkout -b hotfix-1.0.0.1 master
// update version
git commit -a -m "Updated version to 1.0.0.1"
// do a fix

and merged into master and develop branches in a similar way as releases:

git checkout master
git merge --no-ff hotfix-1.0.0.1
git tag v1.0.0.1
git checkout develop
git merge --no-ff hotfix-1.0.0.1
git branch -d hotfix-1.0.0.1

The last thing I do is updating a central repository:

git push
git push --tags

And that's it. I hope you find this short tutorial helpful. If you need more detailed information about things I missed here I suggest reading git tutorials on official Git webpage.