Document that validators comparing state between stage life cycle operations must store that state out-of-band, not on the object

I wonder if we should make StageBase::setMetadata() and getMetadata() public, and use them for this purpose.

These two methods are specifically meant to store arbitrary metadata associated with a particular (claimed) stage. They store it safely in key-value; it's automatically cleaned up at the end of the stage's life.

#4: I wondered the same! 😊 Perhaps we can prefix key-value pairs set by this public function setMetadata() with "external-" and add a new private function setInternalMetadata() with "internal-"?

We now have \Drupal\package_manager\StageBase::setMetadata see 📌 LockFileValidator should store the lock file hash in the stage's metadata, rather than directly in state Needs work . So I think we can close this