I am trying to create a review of an existing and pushed commit.
It appears that arc's automagic considers only non-pushed commits [^1]. So I need to overwrite that somehow and force it to create a revision from the commit I point it to, no matter whether it is included in any remote branch or not. I find myself unable to do so. The [arc diff documentation](https://secure.phabricator.com/book/phabricator/article/arcanist_diff/) does not seem to cover this.
[^1]: I needed to push, to get the change out of the machine where I was writing it originally.
$ arc which REPOSITORY To identify the repository associated with this working copy, arc followed this process: Configuration value "repository.callsign" is empty. Configuration value "project.name" is set to "phabricator"; this project is associated with the "P" repository. Found a unique matching repository. This working copy is associated with the P repository. COMMIT RANGE If you run 'arc diff', changes between the commit: 010dcf6afe0c4f4b Allow the LDAP authentication provider to hide its login form ...and the current working copy state will be sent to Differential, because it is the merge-base of 'origin/feat/ldap-hide-loginform' (the Git upstream of the current branch) HEAD. You can see the exact changes that will be sent by running this command: $ git diff 010dcf6afe0c4f4b..HEAD These commits will be included in the diff: (No commits.) MATCHING REVISIONS These Differential revisions match the changes in this working copy: (No revisions match.) Since there are no revisions in Differential which match this working copy, a new revision will be created if you run 'arc diff'.