A deploy no longer rolls past a plugin that stopped being baked

Before an environment moves to a new platform release, it checks that every package it has installed has been prepared for that release. If something is missing, the update is held and the reason is recorded — otherwise the environment would come up recompiling that content from source on every start, slowly and sometimes not at all.

That check was passing when it should have held.

What was wrong

The check has two halves: which packages must be prepared (the expected set) and which ones actually were (what it finds). The second half was right. The first half was being worked out by looking at the same storage the check was about to inspect — a package counted as "ships content" only if it already had a prepared build there.

So the moment a package's build stopped being produced, that package quietly dropped out of the list of things being asked about. It was no longer missing; it was no longer expected. Every subsequent update went through cleanly, reporting nothing wrong, about exactly the package that had broken. In the extreme — a storage location with nothing prepared in it at all — the entire content half of the check had nothing to compare and still reported success.

This is what let environments move forward while course content had not been properly built.

What changes

The expected set is now taken from what the environment has ever been able to use — every platform build recorded in its storage, not just the one it happens to be running. A package that has once shipped a prepared build stays on the list permanently, so a build that regresses to nothing now holds the update instead of excusing itself from the question.

• Updates hold, and say which packages and why. The reason names each package that is missing a prepared build for the target release.
• A package that genuinely ships no such content is still not asked for one. Nothing that has never produced a build is suddenly demanded — an environment held forever would be a worse problem than the one being fixed.
• "Nothing is prepared here" is now stated rather than passed over. An environment whose storage holds nothing at all is reported as one the check does not apply to, with the reason written to the log, instead of quietly counting as a pass.
• The expected count is logged, so it is possible to see that the check looked at something.

No action is needed. An environment that is currently missing prepared content for a package will now hold its next update and say so, which is the intended behaviour.