STUDY VAULT

Mohamed Attia
CS undergrad · visual study notes
Mohamedattiadev

Chapter 6 — Rebase and Squash — Solutions

4 min read

do the assignment first. reading the answer is not the same as doing it, and u will feel like u learned it when u didn’t.

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# 1
git switch -c feat/login
echo "the form"  > login.md && git add . && git commit -m "add login form"
echo "the style" >> login.md && git add . && git commit -m "style the login form"
echo "the fix"   >> login.md && git add . && git commit -m "fix the login typo"
 
# 2
git switch main
echo "main work" >> notes.md && git add . && git commit -m "main moved on"
git log --oneline --graph --all
 
# 3
git switch feat/login
git log --oneline          # write these 3 hashes down somewhere
git rebase main
git log --oneline --graph --all
 
# 4
git log --oneline          # every hash is different
# the commits got a new parent, and a commit contains its parent's hash,
# so they are new objects. same changes, new ids.
 
# 5
git rebase -i HEAD~3
# in the editor, leave the first line as pick, change the other 2 to squash:
#   pick   47b352d add login form
#   squash d38d285 style the login form
#   squash 440ee6a fix the login typo
# save, then in the second editor delete everything and write:
#   add the login form
 
# 6
cat login.md               # all 3 lines are still there
git log --oneline          # but it is 1 commit now
 
# 7
git switch -c feat/clash main
echo "the branch line" > shared.md && git add . && git commit -m "branch edits shared"
git switch main
echo "the main line" > shared.md && git add . && git commit -m "main edits shared"
git switch feat/clash
git rebase main
 
# 8
git status
cat shared.md
# HEAD is MAIN here, not my branch. rebase replays my commits ON TOP of main,
# so main is already checked out and mine is the one being applied.
 
# 9
# edit shared.md, keep what u want, delete the markers
git add shared.md
git rebase --continue
 
# 10
git reset --hard HEAD~1        # put the branch back into a clashing state
git rebase main
git rebase --abort
git status -s                  # clean
 
# 11
git config --global rerere.enabled true
# cause the conflict, fix it, commit
# then undo and cause the exact same conflict again:
git reset --hard HEAD~1
git rebase main
 
# 12
git log --oneline --graph --all

output of 3, after the rebase:

Successfully rebased and updated refs/heads/feat/login.

output of 5, after the squash:

2ee7a49 (HEAD -> feat/login) add the login form
34cbc09 (main) main moved on

output of 8, the file:

<<<<<<< HEAD
the main line
=======
the branch line
>>>>>>> 078785c (branch edits shared)

output of 11, the second time:

Auto-merging shared.md
CONFLICT (content): Merge conflict in shared.md
Resolved 'shared.md' using previous resolution.
  • in step 4, this is the single most important idea in the chapter. rebase does not move ur commits, it rebuilds them. that is why u never do it to something other people already pulled.
  • in step 8, HEAD is main. during a merge, HEAD is u. during a rebase, it is the branch u are landing on. read the markers, not the words “ours” and “theirs”.
  • in step 11, git still stopped and still made u git add it. rerere fills in the answer, it does not finish the job for u.
  • answer for 12: one straight line, no forks, because everything u did in this chapter was rewriting the branch instead of joining it.

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