Arcanist Workflows

Updated 4,525 Days AgoPublic

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Descriptions of Arcanist workflows.

Official epriestley Workflow

This is how I use arc with Git.

I use an amend/rebase mutable-history workflow where each idea is always represented by one commit. I never make checkpoint commits, and I never write Git commit messages, and I never merge. I have two shell aliases:

• wip: ("work in progress") git commit -a -m WIP
• squish: git status && git commit -a --amend -C HEAD

I use TextMate to edit code. The mate commands below invoke the editor, although I usually locate and open files with GUI in the Finder.

To start a new change, I work in feature branches.

$ git checkout master
$ git checkout -b newfeature
$ mate somefile.php
$ wip
$ arc diff

To update a change, I amend it into HEAD.

$ mate somefile.php
$ squish
$ arc diff

To start a new feature which depends on another feature, I branch off the branch. I do this rarely.

$ git checkout newfeature
$ git checkout -b newerfeature
$ mate newfile.php
$ wip
$ arc diff newfeature

To pull in other users' changes to a first-degree branch, I rebase. I do this very rarely.

$ git rebase master

To rebase an nth-degree branch, I cherry-pick. This is usually painless, while using rebase often isn't.

$ git checkout newerfeature
$ git show # copy commit hash
$ git reset --hard newfeature
$ git cherry-pick <hash>

Alternatively, I'll use rebase -i:

$ git checkout newerfeature
$ git rebase -i newfeature

In many cases, just deleting every commit from the interactive rebase except HEAD results in a clean rebase.

To push a change, I use arc land:

$ arc land newfeature

Facebook Workflow

This is the major workflow used at Facebook with Git. It is similar to the "epriestley" workflow, but uses commit templates and rebase -i to handle Nth-degree branches. It uses "--verbatim" and makes commit messages authoritative. It does not use merges or checkpoint commits.

Set your Git commit template to the output of echo '{"edit":"create"}' | arc call-conduit differential.getcommitmessage. When you commit, fill out the template.

To start a new change, work in a feature branch:

$ git checkout master
$ git checkout -b newfeature
$ vim file.php
$ git commit # Fill out template
$ arc diff --verbatim

To update a change, amend:

$ vim file.php
$ git commit --amend
$ arc diff --verbatim

To start a feature which depends on another feature, stack the commits:

$ vim file.php
$ git commit # Fill out template
$ arc diff --verbatim HEAD^

To edit the previous feature, use rebase -i:

$ git rebase -i master
# Now, pick "edit" for the commit you want to edit.

To rebase the stack, use git rebase:

$ git rebase

Facebook pushes changes with git svn dcommit because its backing VCS is SVN. This is unusual.