intra-invariant

Intra-aggregate invariants are consistency rules that must always hold within a single aggregate instance. They are enforced by hooking custom invariant helpers into the aggregate's verifyInvariants() workflow to detect violations during a Unit of Work commit.

To add a new invariant check to an existing aggregate, create a private invariant helper returning a boolean, wire it into verifyInvariants() with the correct state scope, update the INTRA-INVARIANTS block, and add compliance tests.

When verifying invariants, ACTIVE state scope checks the rule only against currently active aggregate instances, while ALL states evaluates the invariant across every state. You select the appropriate scope when wiring the helper into verifyInvariants().

Yes, you need to write tests when adding an intra-invariant to an aggregate. You must add tests covering both compliant states where the invariant holds and violated states where an invariant violation is expected to be thrown.

Verifying invariants on commit during the Unit of Work ensures aggregate consistency regardless of the triggering operation. This approach centralizes rule enforcement and detects violations before data is persisted.