[tensorproduct]

I agree. I thought that this was the whole point of having a CI system.

I don't have a huge amount of experience in open source projects, so maybe they do it differently. Anywhere I've ever worked, not breaking the build and not causing regressions were a prerequisite to getting any pull request serviced. That's how you keep the master from breaking.

On the other hand, building a testing in a clean environment costs money. A company will pay for server time if they believe it's cheaper than developer time (it is). Maybe OS projects just don't have those resources.