Preserve description and default for allOf-wrapped $ref

Instead of delegating to ParseV3SchemaReference (which reads from the
inner $ref), build the Ref from the outer schema so sibling fields
like description, default, and extensions are retained.

Author: bryantbiggs

pkg/util/proto/document_v3.go

@@ -121,9 +121,27 @@ func (d *Definitions) ParseSchemaV3(s *openapi_v3.Schema, path *Path) (Schema, e
 	// allOf containing a $ref, treat it as a reference. This is the OpenAPI 3.0
 	// compliant way to add sibling properties (description, default) alongside
 	// a $ref, since per the spec $ref siblings are ignored.
+	// We build the Ref from the outer schema so that description, default, and
+	// extensions are preserved.
 	if s.GetType() == "" && len(s.GetAllOf()) == 1 {
 		if ref, ok := s.GetAllOf()[0].GetOneof().(*openapi_v3.SchemaOrReference_Reference); ok {
-			return d.ParseV3SchemaReference(ref.Reference, path)
+			xRef := ref.Reference.GetXRef()
+			if !strings.HasPrefix(xRef, "#/components/schemas") {
+				return d.parseV3Arbitrary(s, path)
+			}
+			reference := strings.TrimPrefix(xRef, "#/components/schemas/")
+			if _, ok := d.models[reference]; !ok {
+				return nil, newSchemaError(path, "unknown model in reference: %q", reference)
+			}
+			base, err := d.parseV3BaseSchema(s, path)
+			if err != nil {
+				return nil, err
+			}
+			return &Ref{
+				BaseSchema:  *base,
+				reference:   reference,
+				definitions: d,
+			}, nil
 		}
 	}
 

pkg/util/proto/openapi_test.go

@@ -780,7 +780,7 @@ func TestV3AllOfRef(t *testing.T) {
 							}
 						],
 						"description": "field using allOf-wrapped ref",
-						"default": {}
+						"default": "some-default"
 					}
 				},
 				"x-kubernetes-group-version-kind": [
@@ -855,4 +855,14 @@ func TestV3AllOfRef(t *testing.T) {
 			t.Errorf("allOfRef reference = %q, want %q", ref.Reference(), "Child")
 		}
 	})
+
+	t.Run("allOf-wrapped ref preserves description and default", func(t *testing.T) {
+		field := parent.Fields["allOfRef"]
+		if got := field.GetDescription(); got != "field using allOf-wrapped ref" {
+			t.Errorf("description = %q, want %q", got, "field using allOf-wrapped ref")
+		}
+		if got, want := field.GetDefault(), "some-default"; got != want {
+			t.Errorf("default = %v, want %v", got, want)
+		}
+	})
 }