Merge pull request #4758 from handrews/yaml

v3.2: Clarify JSON-compatible YAML

Author: lornajane

src/oas.md

@@ -171,12 +171,14 @@ The [schema](#schema) exposes two types of fields: _fixed fields_, which have a
 
 Patterned fields MUST have unique names within the containing object.
 
-In order to preserve the ability to round-trip between YAML and JSON formats, YAML version [1.2](https://yaml.org/spec/1.2/spec.html) is RECOMMENDED along with some additional constraints:
+**Note:** While APIs may be described by OpenAPI Descriptions in either YAML or JSON format, the API request and response bodies and other content are not required to be JSON or YAML.
 
-* Tags MUST be limited to those allowed by [YAML's JSON schema ruleset](https://yaml.org/spec/1.2/spec.html#id2803231), which defines a subset of the YAML syntax and is unrelated to [[JSON-Schema-2020-12|JSON Schema]].
-* Keys used in YAML maps MUST be limited to a scalar string, as defined by the [YAML Failsafe schema ruleset](https://yaml.org/spec/1.2/spec.html#id2802346).
+#### JSON and YAML Compatibility
 
-**Note:** While APIs may be described by OpenAPI Descriptions in either YAML or JSON format, the API request and response bodies and other content are not required to be JSON or YAML.
+In order to preserve the ability to round-trip between YAML and JSON formats, YAML version [1.2](https://yaml.org/spec/1.2/spec.html) is RECOMMENDED along with the additional constraints listed in [[!RFC9512]] [Section 3.4](https://www.rfc-editor.org/rfc/rfc9512.html#name-yaml-and-json).
+
+The recommendation in previous versions of this specification to restrict YAML to its "JSON" [schema ruleset](https://yaml.org/spec/1.2/spec.html#id2803231) allowed for the inclusion of certain values that (despite the name) cannot be represented in JSON.
+OAD authors SHOULD NOT rely on any such JSON-incompatible YAML values.
 
 ### OpenAPI Description Structure