What happens when a rule is checked out and another developer processes a case type?

When a rule is checked out in Pega, it means that a developer is making changes to that rule, and it effectively locks the rule from being altered by others until the developer checks it back in. In this situation, if another developer attempts to process a case type that involves the checked-out rule, the application will use the currently active version of the rule that has not been checked out, ignoring the changes being made by the developer who has the rule checked out. This ensures that ongoing processes remain stable and unaffected by uncommitted or in-progress changes, thereby upholding the integrity of the application during development.

The fact that the application relies on the active version reinforces Pega's collaborative environment, allowing developers to work on rules without disrupting the functionality for end users. It allows for safe editing and version control while ensuring that other developers can continue their work unaffected by changes that are not yet finalized.