katrinahigh / gitstructions

What to do if you have to use Git during a test

Don't panic.

Git is awesome and is designed to PROTECT your work. It is a tool to make your life as a creator easier.

Be cool.

• Let's say the repository for the test is called Assessment2, and it was posted by the user zipcoder. That means it lives at the url https://github.com/zipcoder/Assessment2.

• Fork the repo from github so you can have your own separate copy to modify as you see fit. It would be uncool if you could just push changes to someone else's repo, right?

• After you click Fork you should be taken to the location of your new copy. Notice the url is now: https://github.com/**YOUR_USERNAME**/Assessment2

• Now you have your own copy of the repo to do with as you please, and the original owner of the repo (zipcoder) can sleep at night without fear of you changing any of their work. Cool, right?

Set yourself up for success.

Now that you have your own personal copy, you're free to change it however you want. Head to your Terminal and cd into the directory where you'd like the files to be, then tell git to clone your repository.

git clone https://github.com/yourusername/Assessment2i.git

• What git did for you there is:

  • created a new directory
  • downloaded your fork into it
  • set the remote url to the keyword origin so you don't have to type the whole thing again
  • started you out on a branch called master

• That would have been really annoying to do on your own, but git did it for you with one command!

Cover your ass.

• At this point you could start the usual cycle:
  • make changes (write code)
  • stage those changes to be committed (git add changed_files)
  • commit those changes (git commit -m "actually describe your changes")
  • (repeat as many times as you want)
  • [eventually] push all those commits back up to the remote version of your repo

But what if one of the instructors decides they want to change something during the test? If they make the change in their repo, will your fork automatically be changed to reflect the update?

No. That would be uncool. You made a new fork and it belongs to you. Even though 'zipcoder' is the original author, they should not and do not have permission to change your code without your express consent.

In this case, of course you would want the updated version. There are a couple things you can do ahead of time that might save you some grief later.

1. Keep the master branch clean.

Only make commits on master if you feel like you're done with the code you're committing. Pretend like committing code to master is the last time you'll be able to change it before its graded. That's not true, of course, but its a good habit to get into.

Fortunately master is just the first branch you start with. Kinda like the trunk of a tree. You can make as many as you want and call them whatever you want. Furthermore, when you are working and adding and committing on one branch, the others are still exactly the same as you left them.

Make a new branch any time:

git branch development

Sweet, look at the list of branches:

git branch

You should see something like

development

• master

Now there are two branches, master and the new one development. The * is next to your current branch. No one will judge you for how often you check which branch you're on. Its like checking the fridge to see if you need milk before heading to the grocery store. It takes a couple extra seconds, but could save you A LOT of heartache.

Time to check out the new branch.

git checkout development

See what I did there? Calling git branch again should show you the star next to development. This new branch is exactly the same as the branch from which you created it. If you were following along exactly, that means you were in your master branch, so development is now exactly the same. The benefit is that now you can work and commit changes to to this branch while keeping master clean and shiny.

Let's say you do some work and make a few commits on development and you want to add them to master. Make sure any changes you've made since the last commit are committed, then switch back to master

git checkout master

and merge the development branch

git merge development

Everything should go smoothly since development was originally an exact copy of master and you're the only one working on your local files. Now you can push your local version of master back up to origin if you want (git push origin master)

	If you're still afraid you might break something, you can always 
	add/commit your changes, switch to master, then make a new 
	branch from there called fakemaster or whatever. Switch into 
	the fakemaster and try merging. Any havoc you cause is limited 
	to that new branch and master is still clean.

2. Don't change any of the 'test' files.

Merge conflicts are not as scary as they seem, but right now it's better to just avoid them. If you don't make changes to any file under the /src/test/... directory, there won't be any merge conflicts. Period.

If you want to write some extra tests, creating your own test files is totally fine. You can create them in the same place as usual without fear of merge conflicts.

3. Prepare to pull the changes

If you keep master clean, you always have a safe point to go back to. If you don't change any of the original unit test files, there won't be any merge conflicts. Almost done, one more thing to set up ahead of time...how to actually pull down the changes.

Remember when you made a local clone of your remote repo? Git stored that ugly url (https://github.com/**yourusername**/Assessment2) behind an easy-to-remember keyword called origin. Now whenever you want to pull from or push to your remote repo (on gitHub) you just have to say origin. But if the test cases (or anything else) are updated, that's not going to happen at origin. Its going to happen at a different remote repo: https://github.com/**zipcoder**/Assessment2

That's an easy fix: add the other remote address under a different name. zipcoder seems appropriate (these keywords are case sensitive):

git remote add zipcoder https://github.com/zipcoder/Assessment2i.git

Now we still have our own version of the repo at origin but we can also pull down any new changes by using the keyword zipcoder instead.

When you're ready, add/commit your changes, then switch to master. Pull the changes the same way you always do, except specifying the new zipcoder remote instead of the usual origin

git pull zipcoder master

Assuming no typos, your local master branch should now have the updated files. If you were in the middle of something on a different branch, you will have to switch back to that branch and

git merge master

if you want the new changes to show up there too.

4. Carry on.

Business as usual. The changes you pulled down from the zipcoder remote repo will be incorporated into your code locally, and will be included with everything else when you push to your own origin remote repo with git push origin master.

Reminder:

• Check your branch often. When you use commands like pull and merge and commit, the target branch for these commands is the branch you are currently on. For example, if you are on a branch called dev, you can still git pull origin master, but be aware that you are pulling down whatever is on the master branch of the repo at origin and merging that into your local dev branch. That's totally ok, as long as that's what you mean to do. The same goes for push. If you run git push origin master while your dev branch is selected, you will push your local version of dev to the remote version of master. If you want to push to a different branch than master, just change the branch name: git push origin dev

glhf
-v