Advanced git

This is a demo repositository used for the Fall 19 GCC presentation on Advanced git usage.

This repo was originally from the SOCS Gitlab instance but was moved here to keep it availible without a Guelph login.

This repository contains instructions on how to create and add an ssh key to gitlab and github in git-ssh-setup.pdf. This also contains the GitHub Cheetsheet.

Test Rebasing

This repo has 3 branches

• master
• another_branch
• new_branch

The new_branch does not have any conflicting changes with the master branch and is where we will start for the rebase.

The another_branch has conflicting changes with the file file.txt with the master branch and we will rebase that one next.

How to rebase

To perform the rebase make sure you have checkout the branch that you want to move and that you have a local version the other branch as well. (This can be acompleshed by performing a git checkout and a git pull). Then go back to the topic branch and run git rebase master, this will reapply the commits to the top of master.

Reapply all of the commits from one branch onto the top of another branch. This is useful if you want to move your feature branch commits to the after falling behind master.

$ git rebase <branch>

		   topic
			 v
		 F - G 
		/
A - B - C - D - E
	 			 ^
	 			master

If the current branch is topic and you run git rebase master then you would get

		   			  topic
			 		   v
		   		  F' - G' 
				 /
A - B - C - D - E
	 			 ^
	 			master

Oh no I have a conflict!!!

If you have a conflict you can run git am --show-current-patch to show where the conflicts are, then open a text editor and fix the changes. Once the changes are done you can re-add the files using git add <file> then resume the rebase using git rebase --continue. Hurrah it is now fixed!!

Now that you have completed the rebase you will have to push it back to the remote repository. Normally you would do a git push, but in this case that will fail because a rebase will rewrite the history meaning that all of you commits are now different than the ones on the server and yours will be rejected.

You can use the flag --force-with-lease to force the push as long as the remote does not have any commits newer than the ones in the rebase.