Collaboration Practice

Practicing Merges & Conflicts

The purpose of this activity is to practice collaboration with Git and GitHub. You will practice both automatic merges as well as merge conflicts (and resolving those conflicts).

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Task 0: Setting Up

1. Partner up. The directions for this activity are meant for two people. If there is a third person, just rotate drivers/navigators.

2. Notice the files in this repo:
   a. README.md: these directions (do not alter this file)
   b. line-numbers.md: where you will practice!

3. Decide on ONE person to fork this repo. You are the owner. From now on, you will be referred to as the owner. Go ahead and fork this repo.

4. Owner: Settings (repo gear icon) > Left sidebar: Access > Add a collaborator > type your partner's username and then add them. From now on, they will be referred to as the collaborator.

5. Collaborator: check your email. You should receive an email that contains a link to this remote repo and a message saying "You can now push to this repository." Open the invitation and Accept it. (you will NOT fork anything)

6. Both partners: copy the SSH URL of the forked repo (NOT the original). In your IDE, make sure you are in wd/classwork/ and then git clone URL. Then cd into collaboration-practice.

7. Open up: line-numbers.md. This is where you will be doing your coding.

NOTE: after you type each command, make sure you READ what your command line says back to you! For example, if you type commiy instead of commit, you will get an error! If you get into the habit of proofreading, you will save yourself a lot of headache!

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Task 1: Automatic merging (no errors)

1. Owner: add text to line 1 (after 1).
   ex: 1 Alice was here!

2. Collaborator: add text to line 3 (NOT line 2).
   ex: 3 Bob was here!

IMPORTANT SIDENOTE: There must be one extra line BETWEEN the edits. Otherwise, you will get a merge conflict.

3. Owner: add, commit, and push. You shouldn't have any issues.

4. Collaborator: Try to do git pull. You will be prompted with an error that ends with:

Please, commit your changes or stash them before you can merge. 
Aborting.  

a. So following the directions, you must add and commit. Go ahead and do that.
b. Well you're in the habit of doing add, commit, and push, so go ahead and try pushing. You should see an error:

hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Integrate the remote changes (e.g.
hint: 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

c. So you have to do git pull. Then press ^X (control X) to skip adding a "merge message". You should see the changes merged automatically!
d. A quick git status will show you that you still need to push. Do that.

5. Owner: do a git pull to see your collaborator's changes as well!

6. Let's practice again, but this time in the other direction:
   a. This time, collaborator: add some text to line 5, then add/commit/push.
   b. And owner, you add text to line 7.
   c. Repeat the same process as above, but this time so that the owner has to pull.

7. By the end of this Task, both partners should see

1 owner's text
2
3 collaborator's text
4
5 collaborator's text
6
7 owner's text
...

and a git status (for both partners) should say:

On branch master
Your branch is up-to-date with 'origin/master'.

nothing to commit, working directory clean

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Task 2: Merge Conflicts

1. Owner: On line 9, write GitHub is awesome.
   a. Then add, commit, and push.

2. Collaborator: On line 9, write GitHub is really good.
   a. You can add and commit, but just like Task 1, you have to pull before you can push.
   b. You now have your first merge conflict! It should contain:

<<<<<<< HEAD
#### 9 GitHub is really good.
=======
#### 9 GitHub is awesome.
>>>>>>> 7e089a7d32f138cd7e8750eeabf5d80d9812d359

3. Collaborator: You must fix the merge conflict by doing the following:
   a. Remove <<<<<<< HEAD and ======= and >>>>>>> 7e089a7d32f138cd7e8750eeabf5d80d9812d359. This tells Git that you are resolving the merge conflict.
   b. Because you are a human, you can make the smart decision about how to merge these two lines. Let's make it say GitHub is really awesome.
   c. Using git status, you will see that you have to re-add, commit, and now you can push.

4. Owner: pulling will show you the merged line 9.

5. Practice again on line 11, but this time let the Owner resolve the merge conflict. Write whatever sentence you want.

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At this point, you are done! You only need to work on the Extension below if you finish early in class, or just want to!

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Task 3: Extension

Work together to try to make what you see in the screenshot below. You can divide and conquer, but add/commit/pull/push frequently. Hopefully you get both automatic merges and merge conflicts!

All starter code is in extension.html. You can write your HTML inside of <body></body> and your CSS inside of <style></style>.