Conflict Resolution

Let's say we want to add additional changes to our add-readme branch 0:00 before merging our pull request into the master branch. 0:03 This is really simple. 0:07 All we need to do is make the changes we want in our text editor, 0:08 commit the changes, and push the branch. 0:11 In this video, however, 0:14 we're going to intentionally create a conflict by making our edits and 0:15 committing the changes on the GitHub website as well as on our local copy. 0:18 This will give you an idea of the editing abilities on GitHub. 0:23 When you're just getting started using Git and 0:25 GitHub, my suggestion is to not make any edits on the website. 0:28 Doing all of your work locally will help you avoid conflicts 0:32 like the one we're about to create. 0:34 If you're only pushing up changes from your local computer and 0:36 working by yourself, you'll always be in sync with the remote repository. 0:39 However, if you do start working with collaborators, 0:43 they might just push up a change to the remote branch while you're working on 0:45 the same file locally, resulting in a conflict. 0:48 This is a fairly common issue, and it's not the end of the world, but 0:51 it can be scary, so let's practice creating and fixing a merge conflict. 0:54 Okay, so I'm here in my code view and I want to change to the add-readme branch. 1:00 Let's say I want to add an image to my README. 1:04 I'll click into the README.md file and click the Edit button here. 1:07 So here's a little hack or a pro tip. 1:14 If I wanna add an image to a readme file, 1:17 the markdown syntax in the markdown cheat sheet will tell us how to do that. 1:20 But a little shortcut is I can go to Issues and 1:24 New Issue. 1:29 And if I have a file like I do here, then I can just drag and 1:33 drop it into the issue body and it creates this automatic URL. 1:40 Or it creates the Markdown syntax that we need. 1:45 So I'll do Preview. 1:48 Cool. 1:51 So I can copy and paste it back here 1:54 and I can preview the changes. 1:58 Awesome. 2:05 So the green shows what I've added and that looks good. 2:06 So I'll go back and edit my file. 2:11 I'll also want to adjust this typo here. 2:13 Files completed and then let's do a, 2:18 And cool, looks good. 2:49 So here I will add a commit messages and 2:51 I can just say update README.md 2:58 to add image and fix typo. 3:04 I can add an optional extended description, and then I can go ahead and 3:09 directly commit the changes to the add-readme branch by 3:13 clicking Commit changes here. 3:17 Back in the console, normally if we have any changes to a remote repository, 3:22 we would use the command git pull to pull in the remote changes. 3:27 As they say, always pull before you push. 3:31 But let's say I forgot that I had made the change on the remote repository, and 3:34 I'm gonna go ahead and add some information to my README here. 3:37 And I'll save. 3:49 So in the console, I'll run the commands. 3:50 Let's make sure I'm in the right branch. 3:55 I'm still in the add-readme branch, great. 4:01 And so I will add and commit my changes. 4:03 Cool. 4:16 And I'll go git push origin, add-readme. 4:17 Okay. 4:34 What's going on? 4:34 It said failed to push. 4:35 Updates were rejected because the remote contains work that you do 4:38 not have locally. 4:42 This is usually caused by another repository pushing to the same ref. 4:44 Okay, so that's right, I forgot to pull, right? 4:47 So now I type git pull origin add-readme. 4:51 And I get a new error message. 5:04 CONFLICT: merge conflict in README.md. 5:05 Automatic merge failed; fix conflicts and then commit the result. 5:09 Okay, so here we can refresh the text editor. 5:13 And we can see there's a bunch of stuff here. 5:22 It looks kind of scary but we'll get through it, I promise. 5:28 Okay, we can see there are a lot of errors or 5:31 conflict markers which show us where the conflict occurred. 5:33 There's an equals sign that separates the two versions. 5:36 On the top, the head is the most recent commit, and 5:40 the one I was trying to push up from my local computer. 5:43 And below the equals signs was the change that I made on GitHub. 5:46 I'll need to choose which to keep. 5:50 I wanna keep the one that has the image, 5:52 so I'll just have to delete all the rest of this here. 5:55 And all these conflict markers, and save. 6:07 And then back in our console, 6:11 we'll do a git status. 6:17 Cool, I'll do a git add. 6:21 git commit -m. We'll go, fixed 6:24 merge conflict, 6:30 and I'll go git push 6:35 origin add-readme. 6:40 Cool. 6:52 Now we'll go back to the Treehouse repository. 6:54 We'll go to the Pull Request. 7:00 You can see my commit history right here, updated README.md file to add 7:05 the image and fix the typo, added my profile locally. 7:10 And then another commit message where I fixed the merge conflict. 7:14 Also, if we go here, we can see this commit history. 7:17 Now that I've added our additional comments and fixed the commit, 7:21 let's go back to our pull request. 7:24 We can see the additional commits to the branch are shown here. 7:26 And let's take another look at the files changed view, too. 7:30 Commits, and the file's changed. 7:38 That's fine. 7:41 Okay, this looks good. 7:44 Now let's click Merge pull request and confirm the merge. 7:46 Confirm merge. 7:53 Pull request successfully merged and closed. 7:55 Woo hoo! 7:58 Congratulations. 7:59 You've completed your first pull request. 8:00 Since we won't be using the add-readme branch any longer, 8:02 we can delete the branch here. 8:05 If we revisit the issue page, we see that the add-readme issue is now closed. 8:08 Because we included fixes number one in our pull request body, 8:13 GitHub took care of closing that issue when the pull request was merged. 8:17 If we go to our profile, we'll see a green square on our contributions graph. 8:21 Great job. 8:25 Let's quickly review what we've done. 8:27 After we opened a pull request, 8:29 we made a change to the repository on the GitHub website. 8:31 Since we forgot to do a git-pull, 8:34 we made a change to the same file on our local computer and we created a conflict. 8:36 In the text editor, we deleted the lines we didn't want to keep and 8:41 then committed and pushed up to the remote repository on GitHub. 8:44 Problem solved. 8:47 In the next stage, 8:49 Kyle will show how to use these features to collaborate on a team. 8:50