Question

When I switch my git to a branch doing a change, I suddenly found a bug that I need to fix.
What should I do?
Do I need to record the bug in a excel or piece of paper then fix it in another branch?
If that is the case, I think git is stupid.

Answer 1

If I got your question right, you need git stash, e.g.

# I have some uncommited changes!
git stash
# now I have a clean working directory, without the uncommited changes. 
# fix Your bug, commit push, etc.
git stash pop
# now my uncommited changes are back! Keep working on the feature