Chapter 5 — Branches and Merging — Solutions

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 branch
 
# 2
git branch -m main          # only if it was called master
 
# 3
git switch -c feat/colortheme
# or:  git checkout -b feat/colortheme
 
# 4
cat .git/HEAD
cat .git/refs/heads/feat/colortheme
 
# 5
echo "dark colors" >> theme.md
git add . && git commit -m "add the dark colors"
echo "more colors" >> theme.md
git add . && git commit -m "add more colors"
 
git switch main
cat theme.md               # No such file or directory. it lives on the other branch.
 
# 6
git merge feat/colortheme
# Fast-forward. main had not moved since u branched, so git only slid the pointer.
 
# 7
git branch -d feat/colortheme
git log --oneline --graph --all
 
# 8
git switch -c feat/conflict
echo "the branch version" > line.md
git add . && git commit -m "line from the branch"
git switch main
echo "the main version" > line.md
git add . && git commit -m "line from main"
git merge feat/conflict
 
# 9
git status
cat line.md
# above the ======= is HEAD, which is main, which is MINE
# below it is feat/conflict, which is what is coming IN
 
# 10
git merge --abort
git status -s              # nothing. as if u never typed merge.
 
# 11
git merge feat/conflict
# edit line.md by hand until it is:
#   the main version
#   the branch version
# and the <<<<<<< ======= >>>>>>> lines are gone
git add line.md
git commit
 
# 12
git switch -c feat/conflict2
echo "branch again" > line.md
git add . && git commit -m "branch again"
git switch main
echo "main again" > line.md
git add . && git commit -m "main again"
git merge feat/conflict2
git checkout --ours line.md
git add line.md
git commit
 
# 13
git worktree add -b hotfix ../practice-hotfix
git worktree list
git worktree remove ../practice-hotfix
git branch -d hotfix
 
# and the refusal:
git worktree add ../practice-main main

output of 6:

Updating 79e91e0..fb31aea
Fast-forward
 theme.md | 2 +
 1 file changed, 2 insertions(+)

output of 8:

Auto-merging line.md
CONFLICT (content): Merge conflict in line.md
Automatic merge failed; fix conflicts and then commit the result.

output of 9, the file:

<<<<<<< HEAD
the main version
=======
the branch version
>>>>>>> feat/conflict

output of 13, the list:

/home/ati/practice-git       fb31aea [main]
/home/ati/practice-hotfix    fb31aea [hotfix]

output of 13, the refusal at the end:

Preparing worktree (checking out 'main')
fatal: 'main' is already used by worktree at '/home/ati/practice-git'

• in step 6 it was a fast forward because main had no commits of its own since the branch was made. there was nothing to combine, so there is no merge commit. do step 8 and u get the other kind, because both sides moved.
• in step 10, --abort is the command to remember. any time a conflict confuses u, this puts u back before it started and costs u nothing.
• in step 12, --ours means the branch u are standing on, which is main. it is not “the good one”, it is “the one i am on”, and during a rebase that flips around.
• in step 13, the refusal is the lesson, not a mistake: u are standing in the worktree that already has main checked out, and a branch can only live in one worktree at a time. that is also why the first half of the step made a new branch instead.

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