SOLUTIONS.md

Solutions

Solutions to the rebasing exercises, all done in the dev-1alice/ directory:

• Switch the order of commits 04-fourth and 05-fifth

  • Start with git rebase -i HEAD~5, switch the lines with those two commits, then save the file. You're done!
  • Graphs:
    • After switching 04 and 05
    • After merging in branch2

• Merge the changes of branch2 into main but NOT the changes of branch1

  • Start in branch2 with git checkout branch2
  • Now do git rebase -i HEAD~8, remove the two commits from branch1, save the file
  • git checkout main
  • git merge branch2
  • That's it, you're done! Verify with git log --pretty=oneline.
  • Graphs:
    • During the middle of rebasing
    • After merging just branch2

• Squash the two commits in branch1 then push to origin

  • Check out the branch: git checkout branch1
  • Rebase the branch and squash the final commit into the previous one, so branch1 only has one commit.
  • Push with git push --force-with-lease
  • Verify by changing into ../repo.git and running git log --pretty=oneline branch1
  • Graphs:
    • Branch1 after both commits have been squashed

• Switch the order of commits 04-fourth and 05-fifth, push to origin

  • Start with git rebase -i HEAD~5, switch the lines with those two commits, then save the file.
  • There are two ways to do this:
    • git pull && git push
      • This is the preferred way, and will cause your (re-written) history to be merged in with what's in origin.
    • git push --force-with-lease
      • This will overwrite what's in origin and is only recommended if you are in a branch that only you work on.
      • The difference between --force-with-lease versus --force is that the latter will overwrite the remote with your changes. --force-with-lease requires that you have the most recent commit (the HEAD) from the remote, to ensure that you don't overwrite changes which were checked in since your last pull. This makes it safer, or at least less unsafe.
  • Verify by changing into ../repo.git and running git log --pretty=oneline
  • Graphs:
    • After 04 has been deleted (removed from main)
    • After 04 has been merged back in to main

• Switch the order of commits 01-first-will-conflict and 02-second-will-conflict, THEN push to origin

  • Start with git rebase -i HEAD~5, switch the lines with those two commits, then save the file.
  • Edit file.txt and resolve the conflicts
  • git add file.txt
    • Note that git log will show a VERY incomplete history at this point. That's fine--you traveled back in time.
  • git commit
  • Running git status tells you that you're not done yet, and tells you what to do next:
  • git rebase --continue
  • Uh oh, we have another conflict because the next commit also changes file.txt.
  • Edit file.txt and resolve the conflicts
  • git add file.txt
  • git commit
  • git rebase --continue
  • At this point, you've now merged your changes into main, let's push them with git push origin.
  • That's it, you're done!
  • Verify by changing into ../repo.git and running git log --pretty=oneline

• Run git rebase -i and delete commit 04-fourth. Then recover it.

  • Use git reflog to find the commit you removed from main.
  • git show COMMIT_ID can be used to confirm it's the commit you want.
  • git merge COMMIT_ID will merge that commit back into main
  • Extra Credit: Use git rebase -i HEAD~5 to move the commit back to its original location
  • There are a few other ways as well. Feel free to play around in Git, that's what this repo is for!

• Switch the order of commits 01-first-will-conflict and 02-second-will-conflict

  • Start with git rebase -i HEAD~5, switch the lines with those two commits, then save the file.
  • Edit file.txt and resolve the conflicts
  • git add file.txt
    • Note that git log will show a VERY incomplete history at this point. That's fine--you traveled back in time.
  • git commit
  • Running git status tells you that you're not done yet, and tells you what to do next:
  • git rebase --continue
  • Uh oh, we have another conflict because the next commit also changes file.txt.
  • Edit file.txt and resolve the conflicts
  • git add file.txt
  • git commit
  • git rebase --continue
  • No more conflicts, so that's it, you're done! Verify with git log.
  • Graphs:
    • Switched 01 and 02
    • After merging in branch2

If the commit history for any of the above look "weird" when you're done, that's because you're rewriting history, so yeah. The tool tig can make the history a little clearer to read.