What Are Branches?

[MUSIC] 0:00 I'm working on a simple program, in the Ruby programming language, 0:09 that takes a series of numbers and decodes it into text. 0:13 Don't worry if you don't know Ruby. 0:16 Anyone familiar with Git will understand the problem I'm about to show you. 0:18 I'm keeping all my code in Git of course, and my decode method has 0:22 already been committed to the repository and shared with my users. 0:25 I've started work on an encode method that will take a string and 0:29 convert it to an array of numbers. 0:33 But now I get a report that there's a bug in the decode method. 0:35 It's suppose to decode each number in the array and 0:39 add it onto the end of the string, but instead, it's replacing the entire string. 0:41 So I stop my work on the encode method and go to fix the decode method. 0:45 I go up and I find the problem, this text = letter line. 0:50 The equals operator causes it to replace the decoded string, 0:54 we need the plus equals operator so that it appends to the string instead. 0:58 Let me save this and suppose I test the change, 1:02 it looks like it's working correctly, and so I decide to commit it. 1:05 I go to my terminal, and I stage the file for committing, git add decode.rb. 1:08 Then I complete the commit with git commit -m Fix bug with appending string. 1:17 Our bug fix is ready to share with users, crisis averted, but 1:24 wait let's look at the code that got committed. 1:28 I'll run git log with the -p flag which will show our changes, uh-oh, 1:31 there in our commit is our incomplete encode method. 1:36 Git has a branches feature to help deal with situations like this. 1:40 You've probably seen fictional books or movies that depict alternate realities 1:45 which are mostly like our own, but a key element of history has been changed. 1:49 Branches are like those alternate histories, you can switch to a branch 1:53 work on code for a new feature, and commit all your changes to that branch. 1:58 If you switch back to your original branch, 2:02 you'll get the original versions of all your files back. 2:04 Switch back to the new branch and you'll get the updated versions back. 2:07 You can create as many branches as you want, and 2:12 switch between them anytime you want. 2:14 Cloned repositories can pull copies of those branches too, and 2:16 switch between them at will. 2:20 This allow collaborators to review changes that are on a branch without affecting 2:21 their own work. 2:25 All Git repositories start with a Master branch, 2:27 your commits go on this branch by default. 2:30 Before beginning work on the encode method, we could have created a branch 2:32 named Encode specifically for work on that feature. 2:36 Commits related to the encode method would go on this Encode branch, 2:39 not the Master branch. 2:43 When we discovered the issue with decode method 2:45 we could have switched back to the Master branch. 2:47 That would reset our source code files back to a version 2:50 that didn't include the Encode method. 2:53 We could then fix the issue, commit our changes to the Master branch, and 2:55 distribute our bug fix to our users, 2:59 without including the incomplete encode method. 3:01 With that done, we can switch back to our Encode branch, which would restore 3:04 the version of our source code that includes the incomplete encode method. 3:07 That source code would also include the bug in the decode method, but our commit 3:11 to fix that bug would be reincorporated once we merge the two branches together. 3:15 We could resume making commits on the Encode branch, 3:21 still without affecting the Master branch. 3:23 When the encoding feature is complete and 3:26 tested, we can use Git to merge the Encode branch into the Master branch. 3:28 That will cause all the commits from the new branch to be 3:33 added to the history of the master branch. 3:35 In our source code, the new method from the Encode branch will be combined with 3:38 the bug fix from the Master branch. 3:42 In the real world, software development can be messy. 3:44 You can find your attention divided between urgent requests for 3:47 new features and fixing bugs. 3:50 Git branches can help you manage this chaos by helping you keep all these 3:52 aspects of your work separate from each other. 3:56 And when you're done, you can easily bring all your work back together 3:59 by merging branches, this course will teach you how. 4:02 We won't be using Treehouse workspaces for this course at all. 4:06 I'll just be working on my local computer in the terminal, 4:09 although it's possible to follow along in workspaces. 4:12 I encourage you to install Git on your computer and 4:15 follow along there instead, see the teacher's notes for more info. 4:17 You shouldn't take this course if you haven't used Git before. 4:22 You need to already know how to stage and commit files, and for 4:25 later videos you'll need to know how to use code hosting services like GitHub. 4:28 If you aren't already familiar with these topics, 4:32 see the teacher's notes on this video's page for links where you can learn more. 4:35 So now you have some idea what branches are. 4:39 In the next video we'll show you how to create a new branch. 4:41