Signing Off Previous Commits

Useful for signing multiple previous commits in cases that you are the only author for (use the following section for multi-contributor signing)

1. Use $ git log to see which commits need to be signed off. Any commits missing a line with Signed-off-by: Example Author <[e-mail]> need to be re-signed.

2. Go into interactive rebase mode using $ git rebase -i HEAD~X where X is the number of commits up to the most current commit you would like to see.

3. You will see a list of the commits in a text file. On the line after each commit you need to sign off, add exec git commit --amend --no-edit -s with the lowercase -s adding a text signature in the commit body. Example that signs both commits:

   ​​​pick 12345 commit message
   ​​​exec git commit --amend --no-edit -s
   ​​​pick 67890 commit message
   ​​​exec git commit --amend --no-edit -s
   

4. If you need to re-sign a bunch of previous commits at once, find the earliest commit missing the sign off line using $ git log and use that the HASH of the commit before it in this command:

   ​ $ git rebase --exec 'git commit --amend --no-edit -n -s' -i HASH.
   

   This will sign off every commit from most recent to right before the HASH.

5. You will probably need to do a force push ($ git push -f) if you had previously pushed unsigned commits to remote.

Instructions for signing off previous commits authored by Daniel Bluhm, sourced from within the Aries-RFCs.

Fixing Broken Signoffs (Multi-Contributor), Commit Author Signoff Mismatch

If the DCO signoff is broken across multiple commits that include other developers or commits with co-signers, the following process can help resolve this issue. The following can also address commit authors not matching the 'Signed-off-by: name email' field.

1. Initiating a git rebase as far back as needing fixing via: git rebase -i COMMIT_HASH_HERE, and then changing all relevant lines/commits from pick to edit.

2. Once on a commit needing fixing, run:

   git commit --amend --no-edit --author="name <email>"

• Additionally, if there are co-signers or multiple signers, the commit author must be the last DCO sign-off in the commit message (including after any co-signers). In order to adjust this you can run git commit --amend --no-verify.
• These can be combined as git commit --amend --author="name <email> --no-verify

3. After the commit, run: git rebase --continue until the next commit needing fixing or the rebase is complete.

Useful StackOverflow answer detailing part of this process.