Add fixing branches guide

org-cyf-guides/content/reviewing/fixing/index.md

@@ -0,0 +1,122 @@
++++
+title="Fixing a PR Branch"
+description="Learn how to fix a branch that has the wrong files on it"
+time=20
+objectives=[
+    "Correctly make new branches from main",
+    "Recognise when a branch doesn't meet PR requirements",
+    "Fix a branch with the wrong files on it",
+]
++++
+
+## Making a new branch 
+
+While learning at Code Your Future, you will develop lots of projects and backlog tasks.
+While working on projects you will be using branches and PRs in Git and GitHub.
+
+You might be: 
+* Forking projects, working in a branch, and submitting finished backlog items as PRs
+* Working in a team on a project, sharing the work in branches, and reviewing each other with PRs
+
+To make a PR you first need to make a branch and develop some code there.
+Branches are made in Git, on your own machine.
+PRs are made in GitHub.
+
+To avoid problems, you should only create a new branch when you are on the *`main`* branch.
+
+### In VS Code
+Here is a summary of the correct way to make a branch in VS Code:
+
+1. You are ready to start a new piece of work
+2. Switch back to the main branch in VS Code by clicking on the branch name
+3. Create a new branch, named for the thing you are about to work on
+4. Start editing and making commits
+
+You can see extra guidance for how to [manage branches on VS Code here](https://code.visualstudio.com/docs/sourcecontrol/branches-worktrees).
+
+If you are working on multiple tasks at once, always check which branch you are currently working in, so you do not commit to the wrong one.
+
+### Command line
+If you are using the command line, you do it this way:
+
+```sh
+# move to the right directory
+cd your-code-directory
+# switch back to the main branch
+git switch main
+# make a new branch and switch to it
+git switch -c your-new-branch-name 
+# the first time you push on a new branch, tell github you are using a new branch:
+git push --set-upstream origin your-new-branch-name
+# afterwards you can simply use
+git push
+
+```
+
+Before you make a commit, you can check which branch you are currently on using the `git status` or `git branch` command.
+Take care to do this if you are working on multiple tasks at once.
+
+
+## Spotting Problems with Branches
+When you are [submitting a PR on GitHub](/guides/reviewing/trainee-pr-guide/), always check to see if you received automated feedback from bots.
+
+Sometimes, a bot will leave a comment like this:
+
+```text
+The files changed in this PR don't match what is expected for this task.
+Please check that you committed the right files for the task, and that there are no accidentally committed files from other sprints.
+Please review the 'files changed' tab at the top of the page.
+Here is an example of a file that has been incorrectly committed: 
+```
+
+Always read and follow the bot's instructions.
+The first thing you should do is have a look for the example file given in the _files changed_ tab on your PR.
+This tab shows you everything you have changed in the branch you are submitting to the PR.
+You can check it by clicking the link labelled _files changed_ at the top of the page:
+
+![The files changed tab at the top of a pull request page on GitHub](files-changed.png)
+
+Then, have a look at the file tree on the left of the page:
+
+![File tree with multiple projects changed at once](bad-file-tree.png)
+
+You will see 3 types of file, all of these represent "changes" from the original:
+* **Green +** icon means newly created files
+* **Red -** icon means you deleted this file
+* **Grey ±** icon means you made some changes to an existing file
+
+Think about the folders these files are in.
+If the PR you are working on is, for example, a _wireframe_ task, you should only be submitting changes in the _wireframe_ directory.
+In the example above, we see changes have been made outside that directory, in the _form controls_ directory.
+This lets us know that something has not been committed in the right place.
+
+Your own personal projects may not have a bot to check this, so it is worth double-checking the files changed tab yourself when you make a PR to ensure only the right changes are being submitted.
+
+## Fixing a branch which changed the wrong files
+
+The most common cause of branches having the wrong files are:
+* You forgot to go back to `main` before branching
+* You were working on multiple tasks and forgot to switch branch
+
+To solve the problem, what we want to do is put the files back the way they were originally, before you made the changes.
+This is called "reverting".
+There are several ways to do this with git and VS code, the simplest one requires you to use the terminal.
+
+### Using the terminal
+1. Identify which branches are your "original branch", and which one is your "pr branch" with changes
+    * For this example, we will imagine the original is `main` and the pr branch is `wireframe`
+2. Identify which directory or file has the incorrectly changed files we want to revert
+    * For this example, we will be reverting the whole `Form-Controls/` directory
+3. Open the terminal in VS Code
+4. Check you are in the right directory where your code is
+5. Make sure you are on the PR branch by typing `git switch wireframe`
+6. Check out all the original files using this command: `git checkout main Form-Control`
+    * This tells git to look at the main branch, and check out every file in the Form-Control directory, into the current wireframe branch
+
+You now need to re-commit these files and push them.
+You can do this the normal way in VS Code, or in the command line.
+Once you have done these steps, go back to the PR page on GitHub and check the "files changed" tab.
+It should no longer show the incorrectly changed files and only have the ones you intended.
+
+You can also use this technique if you were working on multiple tasks in different branches and incorrectly committed to the wrong branch.
+To do this, swap around the `main` and `wireframe` in the above instructions to match whichever branch you are currently on, and which one you want to check files out from.

org-cyf-guides/content/reviewing/trainee-pr-guide/index.md

@@ -42,7 +42,7 @@ To keep your exercise branch clean:
 
 3. **Make only related changes**.
    - Add or modify only the files in the folder related to the exercise.
-   - If you accidentally change files for another task, you will need to [revert](https://stackoverflow.com/a/37972822) them before submitting your PR for review
+   - If you accidentally change files for another task, you will need to [revert](/guides/reviewing/fixing) them before submitting your PR for review
 
 ### Keeping code clean