fix(v3): retain full JSON pointer path on OpenAPI 3.0 schema references

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

@@ -397,7 +397,9 @@ public static IOpenApiSchema LoadSchema(JsonNode node, OpenApiDocument hostDocum
             if (pointer != null)
             {
                 var reference = GetReferenceIdAndExternalResource(pointer);
-                return new OpenApiSchemaReference(reference.Item1, hostDocument, reference.Item2);
+                var result = new OpenApiSchemaReference(reference.Item1, hostDocument, reference.Item2);
+                result.Reference.SetJsonPointerPath(pointer, context.GetLocation());
+                return result;
             }
 
             var schema = new OpenApiSchema();

test/Microsoft.OpenApi.Readers.Tests/V3Tests/OpenApiSubschemaReferenceTests.cs

@@ -0,0 +1,64 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+using Microsoft.OpenApi;
+using Microsoft.OpenApi.Reader;
+using Microsoft.OpenApi.Tests;
+using Xunit;
+
+namespace Microsoft.OpenApi.Readers.Tests.V3Tests
+{
+    [Collection("DefaultSettings")]
+    public class OpenApiSubschemaReferenceTests
+    {
+        private const string Document = @"
+openapi: 3.0.3
+info:
+  title: Subschema references
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    User:
+      type: object
+      properties:
+        name:
+          type: string
+        address:
+          type: object
+          properties:
+            city:
+              type: string
+    name:
+      type: integer
+    UserName:
+      $ref: '#/components/schemas/User/properties/name'
+    UserCity:
+      $ref: '#/components/schemas/User/properties/address/properties/city'
+";
+
+        [Fact]
+        public void ReferenceToComponentPropertyResolvesToThatProperty()
+        {
+            var document = OpenApiDocument.Parse(Document, "yaml", SettingsFixture.ReaderSettings).Document;
+
+            var userName = Assert.IsType<OpenApiSchemaReference>(document.Components.Schemas["UserName"]);
+
+            Assert.NotNull(userName.Target);
+            Assert.Equal(JsonSchemaType.String, userName.Target.Type);
+            Assert.Equal("#/components/schemas/User/properties/name", userName.Reference.ReferenceV3);
+        }
+
+        [Fact]
+        public void ReferenceToNestedComponentPropertyResolvesToThatProperty()
+        {
+            var document = OpenApiDocument.Parse(Document, "yaml", SettingsFixture.ReaderSettings).Document;
+
+            var userCity = Assert.IsType<OpenApiSchemaReference>(document.Components.Schemas["UserCity"]);
+
+            Assert.NotNull(userCity.Target);
+            Assert.Equal(JsonSchemaType.String, userCity.Target.Type);
+            Assert.Equal("#/components/schemas/User/properties/address/properties/city", userCity.Reference.ReferenceV3);
+        }
+    }
+}