Bors-NG is a GitHub app that prevents merge skew: A problem where patches work at review time but don’t work when they’re actually merged because the main branch changed in the meantime. The classic example is when one patch renames a function, while another patch adds a call to it by its old name and nobody notices because they’re reviewed separately. In a traditional, continuous testing system where tests are run only after the main branch gets updated, this means reverting the faulty patch. But doing this at scale is annoying. Deciding which patch is the bad one can be complicated,…