Merge pull request #1281 from alistairjevans/docs-links-and-improvements

In-progress links in exception messages (plus misc exception msg improvements)

src/Autofac/Core/Activators/Reflection/ReflectionActivator.cs

@@ -290,12 +290,24 @@ private string GetBindingFailureMessage(BoundConstructor[] constructorBindings)
             reasons.Append(invalid.Description);
         }
 
-        return string.Format(
-            CultureInfo.CurrentCulture,
-            ReflectionActivatorResources.NoConstructorsBindable,
-            ConstructorFinder,
-            _implementationType,
-            reasons);
+        if (ConstructorFinder is DefaultConstructorFinder)
+        {
+            // Simplify the text for the common default finder case (to make the message easier to understand).
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                ReflectionActivatorResources.NoConstructorsBindableDefaultBinder,
+                _implementationType,
+                reasons);
+        }
+        else
+        {
+            return string.Format(
+                CultureInfo.CurrentCulture,
+                ReflectionActivatorResources.NoConstructorsBindable,
+                ConstructorFinder,
+                _implementationType,
+                reasons);
+        }
     }
 
     private void InjectProperties(object instance, IComponentContext context)

src/Autofac/Core/Activators/Reflection/ReflectionActivatorResources.resx

@@ -126,4 +126,9 @@
   <data name="NoConstructorsBindable" xml:space="preserve">
     <value>None of the constructors found with '{0}' on type '{1}' can be invoked with the available services and parameters:{2}</value>
   </data>
-</root>
+  <data name="NoConstructorsBindableDefaultBinder" xml:space="preserve">
+    <value>None of the constructors found on type '{0}' can be invoked with the available services and parameters:{1}
+
+See https://autofac.rtfd.io/help/no-constructors-bindable for more info.</value>
+  </data>
+</root>

test/Autofac.Test/Core/Activators/Reflection/ReflectionActivatorTests.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Autofac Project. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
+using System.Reflection;
 using Autofac.Core;
 using Autofac.Core.Activators.Reflection;
 using Autofac.Test.Scenarios.ConstructorSelection;
@@ -180,7 +181,7 @@ public void NonPublicConstructorsIgnored()
         var dx = Assert.Throws<DependencyResolutionException>(() =>
             invoker(Factory.CreateEmptyContainer(), Factory.NoParameters));
 
-        Assert.Contains(typeof(DefaultConstructorFinder).Name, dx.Message);
+        Assert.Contains(typeof(InternalDefaultConstructor).Name, dx.Message);
     }
 
     [Fact]
@@ -338,6 +339,20 @@ public void ConstructorSelectorCannotReturnInvalidBinding()
         Assert.Throws<InvalidOperationException>(() => invoker(container, Factory.NoParameters));
     }
 
+    [Fact]
+    public void CustomBinderNameIncludedInErrorMessage()
+    {
+        var target = Factory.CreateReflectionActivator(typeof(InternalDefaultConstructor), new SimpleConstructorFinder());
+
+        // Constructor finding happens at pipeline construction; not when the pipeline is invoked.
+        var invoker = target.GetPipelineInvoker(Factory.CreateEmptyComponentRegistry());
+
+        var dx = Assert.Throws<DependencyResolutionException>(() =>
+            invoker(Factory.CreateEmptyContainer(), Factory.NoParameters));
+
+        Assert.Contains(typeof(SimpleConstructorFinder).Name, dx.Message);
+    }
+
     private class MisbehavingConstructorSelector : IConstructorSelector
     {
         public BoundConstructor SelectConstructorBinding(BoundConstructor[] constructorBindings, IEnumerable<Parameter> parameters)
@@ -346,6 +361,11 @@ public BoundConstructor SelectConstructorBinding(BoundConstructor[] constructorB
         }
     }
 
+    private class SimpleConstructorFinder : IConstructorFinder
+    {
+        public ConstructorInfo[] FindConstructors(Type targetType) => targetType.GetDeclaredPublicConstructors();
+    }
+
     public class AcceptsIntParameter
     {
         public AcceptsIntParameter(int i)

test/Autofac.Test/Factory.cs

@@ -82,6 +82,16 @@ public static ReflectionActivator CreateReflectionActivator(Type implementation,
             properties);
     }
 
+    public static ReflectionActivator CreateReflectionActivator(Type implementation, IConstructorFinder customFinder)
+    {
+        return new ReflectionActivator(
+            implementation,
+            customFinder,
+            new MostParametersConstructorSelector(),
+            NoParameters,
+            NoProperties);
+    }
+
     public static ReflectionActivator CreateReflectionActivator(Type implementation, IConstructorSelector customSelector)
     {
         return new ReflectionActivator(