Adding a condition to Content CopyToPublishDirectory to validate that the file exists before trying to copy it to output, to keep the same functionality as it existed in PJ. In MSBuild world, without this condition, CopyToPublishDirectory will fail.

TestAssets/TestProjects/WebAppWithMissingFileInPublishOptions/Services/ISmsSender.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace WebApplication.Services
+{
+    public interface ISmsSender
+    {
+        Task SendSmsAsync(string number, string message);
+    }
+}