changing the last commit message without committing newest changes

Question

My ideal workflow would consist of the following steps

1. edit the code
2. compile
3. git commit -a -m "commit message"
4. start running the new binaries, tests, etc. (may take 10+ minutes)
5. start new changes, while the binaries are still running
6. when step # 4 is finished, edit the commit message from step # 3, without committing the changes introduced in step # 5, by adding, say, "test FOO failed"

I cannot use git commit -a --amend -m "new commit message", because this commits the new changes as well. I'm not sure that I want to bother with staging or branching. I wish I could just edit the commit message without committing any new changes. Is it possible?

Answer 1

There's no need to stash or do anything else here.

git commit --amend -m 'Your new message.'

will not commit any new changes (note the lack of -a flag), provided that you haven't explicitly added them to the index (using git add, for example).

Answer 2

Just:

$ git stash
$ git commit --amend -m "Your Modified Message"
$ git stash apply