Synthetic Step Identifiers

Synthetic steps are generated from aspects. The runtime mapping uses a deterministic identifier, so placement is stable across builds.

Canonical identifier

<AspectId>.<Type>

• AspectId: the aspect class name or declared aspect id.
• Type: the synthetic type token (e.g., SideEffect, Validation, Observe, Cache).

Examples:

• ObserveLatency.SideEffect
• Retry.Validation

Disambiguation suffix

If multiple synthetics exist for the same <AspectId>.<Type>, append a suffix:

<AspectId>.<Type>@before
<AspectId>.<Type>@after
<AspectId>.<Type>@around
<AspectId>.<Type>@<index>

Examples:

• ObserveLatency.SideEffect@before
• ObserveLatency.SideEffect@after
• ObserveLatency.SideEffect@2

Resolution rules

• If only a single synthetic exists for <AspectId>.<Type>, the unsuffixed id is valid.
• If multiple exist, the unsuffixed id is rejected with a clear error.
• @<index> is zero-based and stable based on the compiler expansion order.

Versioning considerations

• The identifier format is stable and versionable.
• Renaming an aspect or changing its expansion order should be treated as a breaking change for mapping.