Git: how to melt a commit to another commit? [duplicate]

Question

Let's say I have git commit history like this(newer -> older):

C -> B -> A

after C's commit, I came to realize that there is something wrong with A.Maybe a test case which is suppose to be in that commit,but actually it wasn't there. So how can I deal with this situation? Make a new commit and melt it into A?how?

Problem solved:

1. git checkout A
2. git checkout -b fix
3. edit
4. git add files
5. git commit --amend
6. git rebase fix master

Answer 1

A lot of persons will said to you to do rebase --interactive (which could be the solution) but if you plan to change some lines that had been changed in commits B or C, that will be a hell to use.

The another solution could be :

1. Create and checkout a branch on commit A
2. Amend the commit A or create a new commit (depend on what sense you give to what you want to do)
3. Checkout the previous branch which is still on commit C
4. Use rebase --onto to rebase only commit B and C on the newly created branch (that you could delete after)