Merge #147: github-merge: Add option to overwrite user email

8d229f8 github-merge: Add option to overwrite user email (MarcoFalke)
05df58e github-merge: Set git user name to merge-script (MarcoFalke)

Pull request description:

  The merge script claims authorship of the merge commit, which is confusing:
  * The maintainer didn't author the merged code, nor the merge commit. Everything is done by the script.
  * In case of breach of a git hosting platform, such as GitHub, or the account of a maintainer, the hosting platform would allow a signed commit (signed by the hosting platform) to be pushed in the name of the maintainer. Thus, ...
  * ... the important thing to check for is the commit signature or the actual code changes, not the name (or email) of the maintainer.
  * Most modern software projects attribute their merges to a "merge" account, regardless of who triggered the merge. (For example, rust-lang)

  Solve this issue by:
  * Setting the git user name (committer and author) to "merge-script".
  * (optional) Allowing the maintainer to provide an email to use for the merge commit.

  Just as before, the merge commit is still required to be signed by the maintainer.
  Just as before, the git hosting platform will still denote which account was used to push the changes.

ACKs for top commit:
  hebasto:
    ACK 8d229f8, I have reviewed the code and it looks OK.

Tree-SHA512: 96b8468191d626cd54fab4aec26ae53109ca2967c7a1a19cd88fcb7bf6c7b43768b5e4d0677ec2228da856c75242fa3cabbc9cb7fdd5514f79af9dbe176a6a52

Author: fanquake

github-merge.py

@@ -264,6 +264,7 @@ def parse_arguments():
         githubmerge.pushmirrors (default: none, comma-separated list of mirrors to push merges of the master development branch to, e.g. `git@gitlab.com:<owner>/<repo>.git,git@github.com:<owner>/<repo>.git`),
         user.signingkey (mandatory),
         user.ghtoken (default: none).
+        githubmerge.merge-author-email (default: Email from git config),
         githubmerge.host (default: git@github.com),
         githubmerge.branch (no default),
         githubmerge.testcmd (default: none).
@@ -283,6 +284,7 @@ def main():
     repo = git_config_get('githubmerge.repository')
     host = git_config_get('githubmerge.host','git@github.com')
     opt_branch = git_config_get('githubmerge.branch',None)
+    merge_author_email = git_config_get('githubmerge.merge-author-email',None)
     testcmd = git_config_get('githubmerge.testcmd')
     ghtoken = git_config_get('user.ghtoken')
     signingkey = git_config_get('user.signingkey')
@@ -456,7 +458,10 @@ def main():
             reply = ask_prompt("Type 's' to sign off on the above merge, or 'x' to reject and exit.").lower()
             if reply == 's':
                 try:
-                    subprocess.check_call([GIT,'commit','-q','--gpg-sign','--amend','--no-edit'])
+                    config = ['-c', 'user.name=merge-script']
+                    if merge_author_email:
+                        config += ['-c', f'user.email={merge_author_email}']
+                    subprocess.check_call([GIT] + config + ['commit','-q','--gpg-sign','--amend','--no-edit','--reset-author'])
                     break
                 except subprocess.CalledProcessError:
                     print("Error while signing, asking again.",file=stderr)