Sourcing::X::OptimisticLocked

Exception thrown when optimistic locking fails during event emission. Indicates that another process has modified the aggregate state since the expected version was read.

Attributes

Attribute	Type	Description
$.type	Mu:U	The aggregation type that failed to emit
$.ids	Hash	The projection IDs of the aggregate instance
$.expected-version	Int	The version the command expected
$.actual-version	Int	The version actually found in the store

Message

The exception message includes all context for debugging:

<sourcing optimistic locked: type=BankAccount, ids={:account-id(1)}, expected-version=2, actual-version=3>

When It's Thrown

• Inside the is command retry loop when a concurrent modification is detected
• After all 5 retry attempts have been exhausted (re-thrown to the caller)
• When calling the version-checked emit method directly with a stale version

Handling the Exception

try {
    $account.withdraw(100);
    CATCH {
        when Sourcing::X::OptimisticLocked {
            say "Concurrent modification detected";
            say "Expected version: ", .expected-version;
            say "Actual version:   ", .actual-version;
            # Retry manually or inform the user
        }
    }
}

See Also

• Optimistic Locking Concept — how concurrency control works
• Commands Concept — the automatic retry behavior
• Sourcing::Plugin::Memory — where the CAS check happens