lauwien / branching

branching

The purpose of this repository is to show in the code-and-tell of the weekly MESSAGEix meeting

• what a commit is,
• what GitHub does if you push a commit to your branch and
• what happens if you merge/rebase.

The goal of this code-and-tell is to deepen the understanding of what git does with different commands you give, and the impacts they have on the commit history/your branch.

To see the current commit history of the repository, please check out Insights > Network.

branching's Issues

Holiday Homework :gift: :santa: :christmas_tree:

Rebase/merge branches

1. Fork and clone the repository to your computer.
2. Rebase
   a. Checkout branch feature/b.

   $ git checkout feature/b
   

   b. Checkout a new branch.

   $ git checkout -b your_name/feature/b
   

   c. Open a text file, make a change and add the change to the branch via commit.

   $ git commit changed_file
   

   d. Interactively rebase your_name/feature/b with main while squashing your last commit with the commit before (mark as "squash") and dropping another commit of your preference with (mark as "drop").

   $ git rebase -i main
   

   e. Resolve the conflicts as you wish.
   f. Create a PR to main from your_name/feature/b.
   g. Check the commit history.
   h. Write in the PR description what rebase did to the commit history.
3. Merge
   a. Do steps 2. a-c with branch feature/a.
   b. Merge main into your_name/feature/a.

   $ git merge main
   

   c. do steps 2. e-g.
   d. Write in the PR description what merge did to the commit history.

Revert/change commits

1. Checkout branch feature/b again and checkout a new branch your_name/revert/feature/b or else.

   $ git checkout feature/b
   $ git checkout -b your_name/revert/feature/b
   

2. Revert this commit 962ecfb.

   $ git revert 962ecfb
   

3. Change a commit with multiple modified/added files.

   $ git rebase -i HEAD~3
   

   This shows you in the pop-up window of the interactive rebase the last three commits. This three commits should be the following now (the last hash of the revert commit differs).

   cbbda1b Modify file1 and file8, add file10
   962ecfb Modify file2
   8a3af32 Revert "Modify file2"
   

4. Mark commit cbbda1b as "edit"
5. Delete file10.txt and delete line 2 in file1.txt (# Another change in feature/b) so the file only has 1 line.
6. Amend the commit and modify the commit message, since file10.txt got deleted and the changes in file1.txt won't be committed.

   $ git commit --amend
   

   The "Changes to be committed" message should look now like the following:

   # Changes to be committed:
   #     modified:   file8.txt
   

7. Create a PR and write in the description in your own words what you did, in what situation these two commands might be helpful or if you already had a situation were this would have come in handy.