When you modify code likely to cause severe conflicts communicate this

This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the collaboration category.

Last Updated: 2021-05-15

In Project S, I moved all of X's lab integration code to a background job. Unfortunately, he didn't pull before working on those features himself the next day. The result - massive conflicts that took two hours to fix.

When you modify a file likely to severely affect someone else on your team, alert them (even though you'd "expect" them to pull every day before starting to code, in reality they might not without reminders).