feat(AIP-123): resource type and message names must align (#1473)

Author: noahdietz

aip/general/0123.md

@@ -28,15 +28,15 @@ In the guidance below, we use the following terms:
   This usually (but not necessarily) matches the hostname that users use to
   call the service. Example: `pubsub.googleapis.com`. This is equivalent to an
   [API Group][] in Kubernetes.
-- **Type:** This is the name used for the type within the API. This *should*
-  match the name of the protobuf message. This is equivalent to an [Object][] in
-  Kubernetes.
+- **Type:** This is the name used for the type within the API e.g. the name of
+  the Protobuf `message`. This is equivalent to an [Object][] in Kubernetes.
 
 ## Guidance
 
 APIs **must** define a resource type for each resource in the API, according to
 the following pattern: `{Service Name}/{Type}`. The type name **must**:
 
+- Match the containing API type's name.
 - Start with an uppercase letter.
 - Only contain alphanumeric characters.
 - Be of the singular form of the noun.
@@ -104,6 +104,15 @@ resource:
 
 ## Rationale
 
+### Type and message name alignment
+
+In addition to simple schema-resource coherence and alignment, a number of
+consumers benefit from the `{Type}` and `message` names matching. Consumers have
+simpler lookups, client libraries get the same in addition to aligned user
+experience where resource-oriented code has naming aligned with the generated
+`message` code, generated reference documentation aligns resources with
+`message` docs, etc.
+
 ### Singular and Plural
 
 Well-defined singular and plurals of a resource enable clients to determine the
@@ -124,6 +133,7 @@ such as UpperCamelCase and snake_case.
 
 ## Changelog
 
+- **2025-01-09**: Strongly align resource type and message naming.
 - **2024-08-07**: Added multi-pattern ordering compatibility requirements.
 - **2023-09-19**: Prohibited duplicate pattern variables.
 - **2023-05-06**: Added requirement of singular and plural.