"un-committing" a file from a pushed changeset in gerrit

Question

I have a commit with two files changed (file a and b), I pushed it to gerrit repo (but not yet merged). Now I realize I dont need to update b. How do I push a new changeset that removes/un-commits b and only includes file a?

Answer 1

In your your local repository do the following:

1. Remove file-b from the commit

   git reset HEAD^ -- file-b
   

2. Amend the commit without the file-b

   git commit --amend
   

3. Discard file-b changes

   git checkout -- file-b
   

4. Confirm that everything is OK

   git status
   git log
   git diff HEAD^ HEAD
   

5. Push the new commit to Gerrit (new patchset)

   git push origin HEAD:refs/for/master