Cleanup BootFailedException

src/Umbraco.Core/Exceptions/BootFailedException.cs

@@ -1,9 +1,10 @@
 using System;
+using System.Text;
 
 namespace Umbraco.Core.Exceptions
 {
     /// <summary>
-    /// An exception that is thrown if the Umbraco application cannnot boot.
+    /// An exception that is thrown if the Umbraco application cannot boot.
     /// </summary>
     public class BootFailedException : Exception
     {
@@ -29,5 +30,31 @@ namespace Umbraco.Core.Exceptions
         public BootFailedException(string message, Exception inner)
             : base(message, inner)
         { }
+
+        /// <summary>
+        /// Rethrows a captured <see cref="BootFailedException"/>.
+        /// </summary>
+        /// <remarks>The exception can be null, in which case a default message is used.</remarks>
+        public static void Rethrow(BootFailedException bootFailedException)
+        {
+            if (bootFailedException == null)
+                throw new BootFailedException(DefaultMessage);
+
+            // see https://stackoverflow.com/questions/57383
+            // would that be the correct way to do it?
+            //ExceptionDispatchInfo.Capture(bootFailedException).Throw();
+
+            Exception e = bootFailedException;
+            var m = new StringBuilder();
+            m.Append(DefaultMessage);
+            while (e != null)
+            {
+                m.Append($"\n\n-> {e.GetType().FullName}: {e.Message}");
+                if (string.IsNullOrWhiteSpace(e.StackTrace) == false)
+                    m.Append($"\n{e.StackTrace}");
+                e = e.InnerException;
+            }
+            throw new BootFailedException(m.ToString());
+        }
     }
 }

src/Umbraco.Web/Composing/ModuleInjector.cs

@@ -2,6 +2,7 @@
 using System.Web;
 using Umbraco.Core;
 using Umbraco.Core.Composing;
+using Umbraco.Core.Exceptions;
 
 namespace Umbraco.Web.Composing
 {
@@ -21,16 +22,28 @@ namespace Umbraco.Web.Composing
             {
                 // using the service locator here - no other way, really
                 Module = Current.Container.GetInstance<TModule>();
-                Module.Init(context);
             }
             catch
             {
-                var runtimeState = Current.Container.GetInstance<IRuntimeState>();
-                if (runtimeState.BootFailedException != null)
+                // if GetInstance fails, it may be because of a boot error, in
+                // which case that is the error we actually want to report
+                IRuntimeState runtimeState = null;
+
+                try
                 {
-                    throw new Exception("Failed to boot", runtimeState.BootFailedException);
+                    runtimeState = Current.Container.GetInstance<IRuntimeState>();
                 }
+                catch { /* don't make it worse */ }
+
+                if (runtimeState?.BootFailedException != null)
+                    BootFailedException.Rethrow(runtimeState.BootFailedException);
+
+                // else... throw what we have
+                throw;
             }
+
+            // initialize
+            Module.Init(context);
         }
 
         /// <inheritdoc />

src/Umbraco.Web/UmbracoInjectedModule.cs

@@ -13,6 +13,7 @@ using Umbraco.Web.Routing;
 using Umbraco.Web.Security;
 using Umbraco.Core.Exceptions;
 using Umbraco.Core.Models.PublishedContent;
+using Umbraco.Core.Persistence.FaultHandling;
 using Umbraco.Core.Security;
 using Umbraco.Core.Services;
 using Umbraco.Web.Composing;
@@ -458,19 +459,7 @@ namespace Umbraco.Web
                     // also, if something goes wrong with our DI setup, the logging subsystem may
                     // not even kick in, so here we try to give as much detail as possible
 
-                    Exception e = Core.Composing.Current.RuntimeState.BootFailedException;
-                    if (e == null)
-                        throw new BootFailedException(BootFailedException.DefaultMessage);
-                    var m = new StringBuilder();
-                    m.Append(BootFailedException.DefaultMessage);
-                    while (e != null)
-                    {
-                        m.Append($"\n\n-> {e.GetType().FullName}: {e.Message}");
-                        if (string.IsNullOrWhiteSpace(e.StackTrace) == false)
-                            m.Append($"\n{e.StackTrace}");
-                        e = e.InnerException;
-                    }
-                    throw new BootFailedException(m.ToString());
+                    BootFailedException.Rethrow(Core.Composing.Current.RuntimeState.BootFailedException);
                 };
                 return;
             }