title = Parallelism

[description]

In this zoo, we found a some parallel timelines. What's going on here? The ends of the timelines have little tags attached.

Especially the `bad_ending` one needs our attention! Can you travel to the `good_ending` timeline, and make a new commit where everyone involved is happy?

[congrats]

Whew, good job! This seems like a *much* better outcome.

But our next mission is already waiting...

[setup]

git checkout -b bad_ending

mkdir cage
mkdir toy_shop
echo "Looks very hungry." > cage/lion

echo "A small child.
It really loves cats!
It's holding a lollipop." > child
git add .
git commit -m "The beginning"

mv child cage
git add .
git commit -m "The child is curious"
git branch good_ending

git rm cage/child
echo "Looks happy. :)" > cage/lion
git add .
git commit -m "Oh no"

git checkout HEAD~2
git checkout -b boring_ending
mv child toy_shop
git add .
git commit -m "The child is distracted"

git checkout bad_ending

[win]

# Is the child still there, and do we have a commit that's not in bad_ending?
{ git ls-tree --name-only -r good_ending | grep child; } && { test "$(git log good_ending ^bad_ending --oneline | wc -l)" -gt 0; }