You're trying to push to
refs/publish/master/dicom-heuristic and that is used when you're promoting a change from draft to published. Gerrit requires you to push to refs/for/master/dicom-hauristic for regular commits. You don't have to force anything on gerrit. This is allowed in pure git only. Gerrit will create a new changeset based on change's commit id every time you push again.
The workflow is:
[make changes]
git commit ... <== whatever git command you like
git push origin refs/for/master/dicom-heuristic <== if your origin points to main wireshark's
[make more changes]
git commit -a --amend --no-edit <== or any other git command you like, but beware: --amend is required because you have to keep the change-id
git push origin refs/for/master/dicom-heuristic <== no force of any kind required
AFAIK, you've used refs/publish/master/dicom-heuristic and you've moved your change from draft to published, then you tried to do it again and it failed. Basically gerrit's drafts are not that useful, IMHO, especially in a double-reviewer based system like wireshark's.
Hope it helps.
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