tl;dr. I am working on restoring Harbormaster support for Differentials. Towards this end, GHC's Phabricator instance will soon require that you add an SSH public key to your account in order to upload patches with `arc diff`. Hello everyone, As you are no doubt aware Harbormaster has not been building Differentials for a very long time now. I am currently looking at options for restoring this service but it appears that doing so will require a bit of action on the part of our contributors. Specically, you will need to add an SSH key to Phabricator. You can do so by navigating to the Phabricator Settings [1] page, selecting the "Personal Account Settings" option, and selecting "SSH Public Keys" from the list on the left. There you can click on the "SSH Key Actions" menu on the top-right corner and click on the "Upload Public Key" item. Here you can specify a key name and paste the key contents (e.g. the contents of $HOME/.ssh/id_rsa.pub). The reason for this new requirement is that `arc diff` will soon push submitted diffs to a "staging area", a Git repository managed by Phabricator containing a branch for each submitted Differential. This will allow more reliable Harbormaster builds and merges as we will no longer need to rely on Phabricator correctly applying Differential patches (which has historically been problematic, especially for Differentials where the base commit is unavailable). If there are no objections, I would like to enable the staging area for the rGHC repository in three days, on Monday, 29 August 2016. After this date `arc diff` will try to push submitted differentials to the staging area, which will require a public key. Note, however, that pushing to the staging area can always be disabled with `arc diff`'s `--skip-staging` flag (although we won't be able to run CI builds on Differentials submitted in this way). To be clear: I would have liked to provide an option that did not require key-based authentication, but sadly neither Phabricator nor Gitolite provide any such option. I apologize for the added friction that this new requirement imposes. If enough people feel strongly that this is too onerous then I'm happy to entertain alternative solutions. Cheers, - Ben [1] https://phabricator.haskell.org/settings/