Comment by zokier

I agree on build systems and CI being closely related, and could (in an ideal world) benefit from far tighter integration. But..

> So here's a thought experiment: if I define a build system in Bazel and then define a server-side Git push hook so the remote server triggers Bazel to build, run tests, and post the results somewhere, is that a CI system? I think it is! A crude one. But I think that qualifies as a CI system.

Yes the composition of hooks, build, and result posting can be thought as a CI system. But then the author goes on to say

> Because build systems are more generic than CI systems (I think a sufficiently advanced build system can do a superset of the things that a sufficiently complex CI system can do)

Which is ignoring the thing that makes CI useful, the continuous part of continuous integration. Build systems are explicitly invoked to do something, CI systems continuosly observe events and trigger actions.

In the conclusion section author mentions this for their idealized system:

> Throw a polished web UI for platform interaction, result reporting, etc on top.

I believe that platform integrations, result management, etc should be pretty central for CI system, and not a side-note that is just thrown on top.