fix(library): remove unshipped schema extension fallback

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: baywet

src/Microsoft.OpenApi/Models/OpenApiConstants.cs

@@ -135,11 +135,6 @@ public static class OpenApiConstants
         /// </summary>
         public const string UnevaluatedPropertiesExtension = "x-jsonschema-unevaluatedProperties";
 
-        /// <summary>
-        /// Legacy extension: x-oai-unevaluatedProperties
-        /// </summary>
-        public const string LegacyUnevaluatedPropertiesExtension = "x-oai-unevaluatedProperties";
-
         /// <summary>
         /// Field: Version
         /// </summary>

src/Microsoft.OpenApi/Models/OpenApiSchema.cs

@@ -599,22 +599,18 @@ private void SerializeInternal(IOpenApiWriter writer, OpenApiSpecVersion version
                 // Skip when type is explicitly set to a non-object type (array, string, number, integer, boolean, null).
                 if (!Type.HasValue || (Type.Value & JsonSchemaType.Object) != 0)
                 {
-                    var unevaluatedPropertiesExtensionName = version == OpenApiSpecVersion.OpenApi3_0
-                        ? OpenApiConstants.UnevaluatedPropertiesExtension
-                        : OpenApiConstants.LegacyUnevaluatedPropertiesExtension;
-
                     // Write UnevaluatedPropertiesSchema as extension if present
                     if (UnevaluatedPropertiesSchema is not null)
                     {
                         writer.WriteOptionalObject(
-                            unevaluatedPropertiesExtensionName,
+                            OpenApiConstants.UnevaluatedPropertiesExtension,
                             UnevaluatedPropertiesSchema,
                             callback);
                     }
                     // Write boolean false as extension if explicitly set to false
                     else if (!UnevaluatedProperties)
                     {
-                        writer.WritePropertyName(unevaluatedPropertiesExtensionName);
+                        writer.WritePropertyName(OpenApiConstants.UnevaluatedPropertiesExtension);
                         writer.WriteValue(false);
                     }
                 }

src/Microsoft.OpenApi/PublicAPI.Unshipped.txt

@@ -13,7 +13,6 @@ const Microsoft.OpenApi.OpenApiConstants.Else = "else" -> string!
 const Microsoft.OpenApi.OpenApiConstants.ElseExtension = "x-jsonschema-else" -> string!
 const Microsoft.OpenApi.OpenApiConstants.If = "if" -> string!
 const Microsoft.OpenApi.OpenApiConstants.IfExtension = "x-jsonschema-if" -> string!
-const Microsoft.OpenApi.OpenApiConstants.LegacyUnevaluatedPropertiesExtension = "x-oai-unevaluatedProperties" -> string!
 const Microsoft.OpenApi.OpenApiConstants.PropertyNames = "propertyNames" -> string!
 const Microsoft.OpenApi.OpenApiConstants.PropertyNamesExtension = "x-jsonschema-propertyNames" -> string!
 const Microsoft.OpenApi.OpenApiConstants.Then = "then" -> string!

src/Microsoft.OpenApi/Reader/V3/OpenApiSchemaDeserializer.cs

@@ -300,24 +300,6 @@ internal static partial class OpenApiV3Deserializer
                     }
                 }
             },
-            {
-                OpenApiConstants.LegacyUnevaluatedPropertiesExtension,
-                (o, n, t, c) =>
-                {
-                    if (n is JsonValue)
-                    {
-                        var value = n.GetScalarValue();
-                        if (value is not null)
-                        {
-                            o.UnevaluatedProperties = bool.Parse(value);
-                        }
-                    }
-                    else
-                    {
-                        o.UnevaluatedPropertiesSchema = LoadSchema(n, t, c);
-                    }
-                }
-            },
             {
                 OpenApiConstants.AnchorExtension,
                 (o, n, _, _) => o.Anchor = n.GetScalarValue()