A finished build now always publishes its approval

Before a server will serve a new version of the platform, something has to build the pieces that version needs and then record that the build finished cleanly. That record is the approval every server waits for: until it exists for the exact version a server is running, that server refuses to take traffic.

Only one machine builds at a time. It asks for the job, is handed it, does the work, and writes "done". The next machine in the queue is then handed the job and does the same.

The "done" could go missing, and everything reported success anyway.

The machine writing "done" does not own the record — it sends its change to whoever does. Before sending, it checked one thing for itself: am I still the one holding this job? It asked that of its own local copy of the record, and a local copy can be a moment behind. When the answer came back "no", the machine quietly changed nothing and sent nothing — and the call reported success. Nothing failed, nothing was logged, and the only sign was somewhere else entirely: servers that never became ready, waiting for an approval that was never going to arrive.

The copy it read was usually not merely stale — it was the previous build's own "done". Finishing a build releases the job, so the state left behind says nobody is holding this. That is exactly the answer that makes the next machine's check fail, which is why it was always the second build in a row that vanished and never the first.

Now the machine simply states what happened, and the owner decides what it means. "My build finished, here is its approval" is written unconditionally, under the reporting machine's own name, so it always travels. The owner of the record — which is never out of date about itself — reads that, checks whether the reporter really is the machine holding the job, and publishes the approval, releases the job and hands it to the next machine in one step.

Nothing is lost in the move. A machine whose job was taken away from it mid-build still cannot publish an approval or disturb its replacement's work; that check now simply happens where the answer is reliable. Failures are reported the same way and still block the version from being served, which is the safe direction. The same treatment covers the smaller per-chunk sign-offs a build produces along the way.