I use:

$ git checkout master
$ arc patch --nobranch Dnnn
$ git push

We should probably make arc land prompt instead of failing, though, since there's no technical reason not to let you land others' revisions if you intend to. However, we should also make it respect --author when we do that, so that patches make it to the upstream with the correct metadata.

To prune branches, you can use something like:

$ git branch | cut -c3- | grep arcpatch- | xargs -n1 git branch -D

(The match is arcpatch- instead of arcpatch-D because arc patch --patch some_file.diff generates arcpatch-1.) So you could build arc cleanup as:

$ arc alias cleanup -- '!git branch | cut -c3- | grep arcpatch- | xargs -n1 git branch -D'

You can also put this in a ".arcconfig" file, I believe:

"alias" : {
  "cleanup" : "!git branch | cut -c3- | grep arcpatch- | xargs -n1 git branch -D"
}

I'm not sure what arc cleanup would do beyond that. Git already prevents you from deleting the current branch. The only other thing I can think of is that we could maybe prompt you before deleting any changes not present in Phabricator (by comparing hashes), or provide a --dry-run flag or something, but these don't seem especially useful at first glance...

Those commands won't work under Windows since the command line sucks. Under Windows you have to manually delete all of the branches through the UI.

This use case would also be addressed with better arc land semantics, as discussed in IRC: https://secure.phabricator.com/chatlog/channel/6/?at=65077

I have written this script; it sits under
https://github.com/hach-que/Tychaia/tree/master/Build/Arcanist/workflow as
RedpointCleanupWorkflow.php. Feel free to take it and do whatever you want
with it (e.g. including it in upstream).

@epriestley FYI, I was following your example of defining aliases in arcconfig and I had to do like this.

"aliases" : {                                                                                                                                                                   
    "cleanup" : ["!git branch | cut -c3- | grep arcpatch- | xargs -n1 git branch -D"]
 }

After T182, web-landed changes tend to leave local branches around since we never run any code on the user's machine. These are handled reasonably by arc branch, but having arc cleanup clean them up (or have an option to clean them up) might be nice.

+1 for this command. We have use a web-based UI for landing so our branches stick around locally. To fix this I'm currently using:

arc branches | grep ' Closed ' | sed 's/[^ ]* //' | sed 's/ .*//' | grep -v master | grep -v '^[0-9a-f.]*$' | xargs git br -D

grep -v master | grep -v '^[0-9a-f.]*$'

This part may prove slightly trickier to implement correctly in the general case.

In T3277#254315, @epriestley wrote:

grep -v master | grep -v '^[0-9a-f.]*$'

This part may prove slightly trickier to implement correctly in the general case.

Yeah, that was because my parsing of Closed is wrong. If I have branches with multiple commits on them, arc branch shows all the commits on different lines and puts the Closed on the line of the git SHA and not the branch name. I think if I had the internal data structures present, the hash filtering wouldn't be needed. Not deleting master could probably be done by checking some default upstream things in git but even if it deleted my master branch I wouldn't be super sad.