git create commit from diff between two branches

Question

I have two branches which have very little similar history, but are related to each other.

I want the changes between those two in one git commit.

Answer 1

A simple way to do it is:

• create and checkout branch tmp at branch_a (git branch tmp branch_a && git checkout tmp)
• git reset --soft branch_b
• git commit

that commit must have all the diff