fix: aligns reference copy constructors

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

Author: baywet

src/Microsoft.OpenApi/Models/References/OpenApiCallbackReference.cs

@@ -27,6 +27,14 @@ public class OpenApiCallbackReference : BaseOpenApiReferenceHolder<OpenApiCallba
         /// </param>
         public OpenApiCallbackReference(string referenceId, OpenApiDocument hostDocument, string externalResource = null):base(referenceId, hostDocument, ReferenceType.Callback, externalResource)
         {
+        }
+        /// <summary>
+        /// Copy constructor
+        /// </summary>
+        /// <param name="callback">The reference to copy</param>
+        private OpenApiCallbackReference(OpenApiCallbackReference callback):base(callback)
+        {
+            
         }
 
         internal OpenApiCallbackReference(OpenApiCallback target, string referenceId):base(target, referenceId, ReferenceType.Callback)
@@ -55,9 +63,7 @@ public override void SerializeAsV2(IOpenApiWriter writer)
         /// <inheritdoc/>
         public IOpenApiCallback CreateShallowCopy()
         {
-            return _target is null ?
-                new OpenApiCallbackReference(Reference.Id, Reference.HostDocument, Reference.ExternalResource) :
-                new OpenApiCallbackReference(_target, Reference.Id);
+            return new OpenApiCallbackReference(this);
         }
     }
 }

src/Microsoft.OpenApi/Models/References/OpenApiExampleReference.cs

@@ -28,6 +28,13 @@ public class OpenApiExampleReference : BaseOpenApiReferenceHolder<OpenApiExample
         public OpenApiExampleReference(string referenceId, OpenApiDocument hostDocument, string externalResource = null):base(referenceId, hostDocument, ReferenceType.Example, externalResource)
         {
         }
+        /// <summary>
+        /// Copy constructor
+        /// </summary>
+        /// <param name="example">The example reference to copy</param>
+        private OpenApiExampleReference(OpenApiExampleReference example):base(example)
+        {
+        }
 
         internal OpenApiExampleReference(OpenApiExample target, string referenceId):base(target, referenceId, ReferenceType.Example)
         {
@@ -84,9 +91,7 @@ public override void SerializeAsV2(IOpenApiWriter writer)
         /// <inheritdoc/>
         public IOpenApiExample CreateShallowCopy()
         {
-            return _target is null ?
-                new OpenApiExampleReference(Reference.Id, Reference.HostDocument, Reference.ExternalResource) :
-                new OpenApiExampleReference(_target, Reference.Id);
+            return new OpenApiExampleReference(this);
         }
     }
 }

src/Microsoft.OpenApi/Models/References/OpenApiLinkReference.cs

@@ -31,7 +31,7 @@ public OpenApiLinkReference(string referenceId, OpenApiDocument hostDocument, st
         /// Copy constructor.
         /// </summary>
         /// <param name="reference">The reference to copy</param>
-        public OpenApiLinkReference(OpenApiLinkReference reference):base(reference)
+        private OpenApiLinkReference(OpenApiLinkReference reference):base(reference)
         {
         }
         internal OpenApiLinkReference(OpenApiLink target, string referenceId):base(target, referenceId, ReferenceType.Link)

src/Microsoft.OpenApi/Models/References/OpenApiParameterReference.cs

@@ -31,7 +31,7 @@ public OpenApiParameterReference(string referenceId, OpenApiDocument hostDocumen
         /// Copy constructor
         /// </summary>
         /// <param name="parameter">The parameter reference to copy</param>
-        public OpenApiParameterReference(OpenApiParameterReference parameter):base(parameter)
+        private OpenApiParameterReference(OpenApiParameterReference parameter):base(parameter)
         {
         }
 

src/Microsoft.OpenApi/Models/References/OpenApiSchemaReference.cs

@@ -28,6 +28,13 @@ public class OpenApiSchemaReference : BaseOpenApiReferenceHolder<OpenApiSchema,
         public OpenApiSchemaReference(string referenceId, OpenApiDocument hostDocument, string externalResource = null):base(referenceId, hostDocument, ReferenceType.Schema, externalResource)
         {
         }
+        /// <summary>
+        /// Copy constructor
+        /// </summary>
+        /// <param name="schema">The schema reference to copy</param>
+        private OpenApiSchemaReference(OpenApiSchemaReference schema):base(schema)
+        {
+        }
 
         internal OpenApiSchemaReference(OpenApiSchema target, string referenceId):base(target, referenceId, ReferenceType.Schema)
         {
@@ -196,9 +203,7 @@ public override IOpenApiSchema CopyReferenceAsTargetElementWithOverrides(IOpenAp
         /// <inheritdoc/>
         public IOpenApiSchema CreateShallowCopy()
         {
-            return _target is null ?
-                new OpenApiSchemaReference(Reference.Id, Reference.HostDocument, Reference.ExternalResource) :
-                new OpenApiSchemaReference(_target, Reference.Id);
+            return new OpenApiSchemaReference(this);
         }
     }
 }