fix: link reference annotations parsing

Signed-off-by: Vincent Biret <[email protected]>

Author: baywet

src/Microsoft.OpenApi/Reader/V31/OpenApiLinkDeserializer.cs

@@ -57,7 +57,9 @@ public static IOpenApiLink LoadLink(ParseNode node, OpenApiDocument hostDocument
             if (pointer != null)
             {
                 var reference = GetReferenceIdAndExternalResource(pointer);
-                return new OpenApiLinkReference(reference.Item1, hostDocument, reference.Item2);
+                var linkReference = new OpenApiLinkReference(reference.Item1, hostDocument, reference.Item2);
+                linkReference.Reference.SetMetadataFromMapNode(mapNode);
+                return linkReference;
             }
 
             ParseMap(mapNode, link, _linkFixedFields, _linkPatternFields, hostDocument);

test/Microsoft.OpenApi.Readers.Tests/V31Tests/OpenApiLinkReferenceDeserializerTests.cs

@@ -0,0 +1,38 @@
+using System.Text.Json.Nodes;
+using Microsoft.OpenApi.Reader;
+using Microsoft.OpenApi.Reader.V31;
+using Xunit;
+
+namespace Microsoft.OpenApi.Readers.Tests.V31Tests;
+
+public class OpenApiLinkReferenceDeserializerTests
+{
+    [Fact]
+    public void ShouldDeserializeLinkReferenceAnnotations()
+    {
+        var json =
+        """
+        {
+            "$ref": "#/components/links/MyLink",
+            "description": "This is a link reference"
+        }
+        """;
+
+        var hostDocument = new OpenApiDocument();
+        hostDocument.AddComponent("MyLink", new OpenApiLink
+        {
+            Description = "This is a link description",
+        });
+        var jsonNode = JsonNode.Parse(json);
+        var parseNode = ParseNode.Create(new ParsingContext(new()), jsonNode);
+
+        var result = OpenApiV31Deserializer.LoadLink(parseNode, hostDocument);
+
+        Assert.NotNull(result);
+        var resultReference = Assert.IsType<OpenApiLinkReference>(result);
+
+        Assert.Equal("MyLink", resultReference.Reference.Id);
+        Assert.Equal("This is a link reference", resultReference.Description);
+        Assert.NotNull(resultReference.Target);
+    }
+}