More git awesomeness

As I mentioned in my previous post, working at Enthought involves a lot of forking, commiting, pushing and merging. Git is used for code version control and while I was comfortable working with git earlier, I had to learn a lot of new tricks.

One of the first things I had to learn was branching and PRs, as I had mentioned in the previous post. A note of caution here. Say you're working on adding features to a stable code. In order to add the features and check them, you create a branch called 'features' using

git checkout -b features

Now say, in the middle of this process, you've been asked to fix couple of bugs in the supposedly stable code. To code and submit the fixes, you need to work in a different branch, say 'fix', created using

git checkout -b fix

Here's the catch. You need to create the branch from master/stable and not the features branch you were previous on. So you will have to run the second command after running

git checkout master

This will make sure that the commits or changes you've made don't follow you into the fix branch. Trust me, things will get messy if you don't.

Secondly, it is wise to do

git pull origin master

every morning before starting work because someone else working on the project could've updated the project in the meanwhile. And don't do

git pull url-to-repo

because master/stable wouldn't be automatically updated in that case.

Thirdly, it'll help to know which branch you're working on all the time because you wouldn't want to mix code between branches. In order to do so, the git people have written a code that will change your command prompt in the terminal. Download the following file, preferably place it in your home directory '~' and source it in your '.bashrc' file using 'source'. Doing so will append the name of the branch you're working on in the command prompt itself. Read the file for more ways in which you can add to the prompt.

Finally, git commands aren't supported by the standard bash/zsh auto completion tools/files. To add this, download this file, place it in your home directory and source it like you did with the previous file. Doing so will enable auto complete on git commands in the terminal.

There are a couple of other cool git commands I've come across which are helpful.

git branch --list

will tell you all of the branches you've created in the current repository.

git checkout <file>

will remove the changes you've made in a file and revert it back to the previous commit.

git cherrypick <>

lets you pick specific commits to push.

Ohh, I almost forgot. Once you're done working in a branch and making commits, when the time comes for you to push code to the central repository, use

git push origin branch-name

to push your changes to the relevant branch in the central repository, from which you can submit a PR and merge the codes. This way, you'll have time to catch and correct errors before you push them into the master/stable version of the repository.

PS : The best way to get used to the commands is to use them. A lot. Everyday. So create a github/bitbucket account, create a repository and screw around with it as much as you can, creating and merging branches, submitting PRs and what not.

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