Updates the RequiresExecution logic so we can skip steps based on some user input (i.e. skip the starter kit installation). Fixes the start kit js stuff to update the model correctly and continue. Fixes the error view to restart - it cannot just go back because there might not be a view there.

src/Umbraco.Web/Install/Controllers/InstallApiController.cs

@@ -135,9 +135,9 @@ namespace Umbraco.Web.Install.Controllers
                 {
                     instruction = installModel.Instructions[step.Name];
                 }
-
+                
                 //If this step doesn't require execution then continue to the next one, this is just a fail-safe check.
-                if (step.RequiresExecution() == false)
+                if (StepRequiresExecution(step, instruction) == false)
                 {
                     //set this as complete and continue
                     InstallStatusTracker.SetComplete(installModel.InstallId, stepStatus.Name, null);
@@ -152,7 +152,7 @@ namespace Umbraco.Web.Install.Controllers
                     InstallStatusTracker.SetComplete(installModel.InstallId, step.Name, setupData != null ? setupData.SavedStepData : null);
 
                     //Determine's the next step in the queue and dequeue's any items that don't need to execute
-                    var nextStep = IterateNextRequiredStep(step, queue, installModel.InstallId);
+                    var nextStep = IterateNextRequiredStep(step, queue, installModel.InstallId, installModel);
                     
                     //check if there's a custom view to return for this step
                     if (setupData != null && setupData.View.IsNullOrWhiteSpace() == false)
@@ -164,6 +164,9 @@ namespace Umbraco.Web.Install.Controllers
                 }
                 catch (Exception ex)
                 {
+
+                    LogHelper.Error<InstallApiController>("An error occurred during installation step " + step.Name, ex);
+
                     if (ex is TargetInvocationException && ex.InnerException != null)
                     {
                         ex = ex.InnerException;
@@ -200,23 +203,36 @@ namespace Umbraco.Web.Install.Controllers
         /// <param name="current"></param>
         /// <param name="queue"></param>
         /// <param name="installId"></param>
+        /// <param name="installModel"></param>
         /// <returns></returns>
-        private string IterateNextRequiredStep(InstallSetupStep current, Queue<InstallTrackingItem> queue, Guid installId)
+        private string IterateNextRequiredStep(InstallSetupStep current, Queue<InstallTrackingItem> queue, Guid installId, InstallInstructions installModel)
         {
             if (queue.Count > 0)
             {
                 var next = queue.Peek();
                 var step = InstallHelper.GetAllSteps().Single(x => x.Name == next.Name);
-                
+
                 //If the current step restarts the app pool then we must simply return the next one in the queue, 
                 // we cannot peek ahead as the next step might rely on the app restart and therefore RequiresExecution 
-                // will rely on that too.
-                //Otherwise if it requires execution then of course return it.
-                if (current.PerformsAppRestart || step.RequiresExecution())
+                // will rely on that too.                
+                if (current.PerformsAppRestart)
                 {                    
                     return step.Name;
                 }
-                
+
+                JToken instruction = null;
+                //If this step has any instructions then extract them
+                if (installModel.Instructions.Any(x => x.Key == step.Name))
+                {
+                    instruction = installModel.Instructions[step.Name];
+                }
+
+                //if the step requires execution then return it's name
+                if (StepRequiresExecution(step, instruction))
+                {
+                    return step.Name;
+                }
+
                 //this step no longer requires execution, this could be due to a new config change during installation,
                 // so we'll dequeue this one from the queue and recurse
                 queue.Dequeue();
@@ -225,13 +241,37 @@ namespace Umbraco.Web.Install.Controllers
                 InstallStatusTracker.SetComplete(installId, step.Name, null);
 
                 //recurse
-                return IterateNextRequiredStep(step, queue, installId);
+                return IterateNextRequiredStep(step, queue, installId, installModel);
             }
 
             //there is no more steps
             return string.Empty;
         }
 
+        /// <summary>
+        /// Check if the step requires execution
+        /// </summary>
+        /// <param name="step"></param>
+        /// <param name="instruction"></param>
+        /// <returns></returns>
+        internal bool StepRequiresExecution(InstallSetupStep step, JToken instruction)
+        {
+            var model = instruction == null ? null : instruction.ToObject(step.StepType);
+            var genericStepType = typeof(InstallSetupStep<>);
+            Type[] typeArgs = { step.StepType };
+            var typedStepType = genericStepType.MakeGenericType(typeArgs);
+            try
+            {
+                var method = typedStepType.GetMethods().Single(x => x.Name == "RequiresExecution");
+                return (bool)method.Invoke(step, new object[] { model });
+            }
+            catch (Exception ex)
+            {
+                LogHelper.Error<InstallApiController>("Checking if step requires execution (" + step.Name + ") failed.", ex);
+                throw;
+            }
+        }
+
         internal InstallSetupResult ExecuteStep(InstallSetupStep step, JToken instruction)
         {
             using (DisposableTimer.TraceDuration<InstallApiController>("Executing installation step: " + step.Name, "Step completed"))