And that can be (and is) done with the stacked diffs model as well. CI is orthogonal to whether you use the PR model of the stacked diffs model.

But what commit do you run the CI against? If you run it against a commit that's stacked on top of 3-4 other unreviewed changes, then the CI will include errors from all those other commits, not just yours.

You don't stack against random commits. Only commits that have passed tests before and so are on master, or your own commits.

That's not what the article says:

> Yang sees that the Diff for the “fix” is out for review. Yang uses the Phabricator command line tool to patch that commit on top of master. This means that it’s not a branch. It’s just a throwaway local commit. Yang then starts working on the first change. Yang submits a Diff for review from the command line. Later, the “fix” has changed, so Yang drops the patch of the old version from the Git history and patches in the updated one via interactive rebase.

I guess the CI would have to cherry-pick the PR onto master before running the tests?