Fix null reference error message show in Manage Packages dialog.

Show no package sources error in Manage Packages dialog instead
of null reference error message.

src/AddIns/Misc/PackageManagement/Project/PackageManagement.csproj

@@ -225,6 +225,7 @@
     <Compile Include="Src\ManagePackagesViewTitle.cs" />
     <Compile Include="Src\MSBuildBasedProjectExtensions.cs" />
     <Compile Include="Src\IPackageFromRepositoryExtensions.cs" />
+    <Compile Include="Src\NoPackageSourcesConfiguredException.cs" />
     <Compile Include="Src\NuGetExePath.cs" />
     <Compile Include="Src\NuGetPackageRestoreCommandLine.cs" />
     <Compile Include="Src\PackageLicenseViewModel.cs" />

src/AddIns/Misc/PackageManagement/Project/Src/Design/FakeRegisteredPackageRepositories.cs

@@ -37,7 +37,7 @@ namespace ICSharpCode.PackageManagement.Design
 		
 		public FakePackageRepository FakeRecentPackageRepository = new FakePackageRepository();
 		
-		public IRecentPackageRepository RecentPackageRepository {
+		public virtual IRecentPackageRepository RecentPackageRepository {
 			get { return FakeRecentPackageRepository; }
 		}
 		

src/AddIns/Misc/PackageManagement/Project/Src/NoPackageSourcesConfiguredException.cs

@@ -0,0 +1,30 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System;
+
+namespace ICSharpCode.PackageManagement
+{
+	public class NoPackageSourcesConfiguredException : Exception
+	{
+		public NoPackageSourcesConfiguredException()
+			: base("No package sources configured")
+		{
+		}
+	}
+}

src/AddIns/Misc/PackageManagement/Project/Src/RecentPackagesViewModel.cs

@@ -39,8 +39,6 @@ namespace ICSharpCode.PackageManagement
 				packageViewModelFactory, 
 				taskFactory)
 		{
-			recentPackagesRepository = registeredPackageRepositories.RecentPackageRepository;
-			
 			this.packageManagementEvents = packageManagementEvents;
 			RegisterEvents();
 		}
@@ -52,6 +50,15 @@ namespace ICSharpCode.PackageManagement
 			packageManagementEvents.ParentPackagesUpdated += OnAddRecentPackage;
 		}
 		
+		protected override void UpdateRepositoryBeforeReadPackagesTaskStarts()
+		{
+			try {
+				recentPackagesRepository = RegisteredPackageRepositories.RecentPackageRepository;
+			} catch (Exception ex) {
+				errorMessage = ex.Message;
+			}
+		}
+		
 		protected override void OnDispose()
 		{
 			packageManagementEvents.ParentPackageInstalled -= OnAddRecentPackage;
@@ -66,6 +73,10 @@ namespace ICSharpCode.PackageManagement
 		
 		protected override IQueryable<IPackage> GetAllPackages()
 		{
+			if (recentPackagesRepository == null) {
+				throw new ApplicationException(errorMessage);
+			}
+			
 			return recentPackagesRepository.GetPackages();
 		}
 	}

src/AddIns/Misc/PackageManagement/Project/Src/RegisteredPackageRepositories.cs

@@ -94,6 +94,8 @@ namespace ICSharpCode.PackageManagement
 		
 		void CreateActiveRepository()
 		{
+			EnsureActivePackageSourceIsConfigured();
+			
 			if (ActivePackageSource.IsAggregate()) {
 				activePackageRepository = CreateAggregateRepository();
 			} else {
@@ -101,6 +103,13 @@ namespace ICSharpCode.PackageManagement
 			}
 		}
 		
+		void EnsureActivePackageSourceIsConfigured()
+		{
+			if (ActivePackageSource == null) {
+				throw new NoPackageSourcesConfiguredException();
+			}
+		}
+		
 		public void UpdatePackageSources(IEnumerable<PackageSource> updatedPackageSources)
 		{
 			PackageSources.Clear();

src/AddIns/Misc/PackageManagement/Test/Src/AvailablePackagesViewModelTests.cs

@@ -390,7 +390,7 @@ namespace PackageManagement.Tests
 			CreateViewModel(exceptionThrowingRegisteredPackageRepositories);
 			viewModel.ReadPackages();
 			
-			ApplicationException ex = Assert.Throws<ApplicationException>(() => CompleteReadPackagesTask());
+			ApplicationException ex = Assert.Throws<ApplicationException>(CompleteReadPackagesTask);
 			Assert.AreEqual("Test", ex.Message);
 		}
 		

src/AddIns/Misc/PackageManagement/Test/Src/Helpers/ExceptionThrowingRegisteredPackageRepositories.cs

@@ -17,6 +17,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System;
+using ICSharpCode.PackageManagement;
 using ICSharpCode.PackageManagement.Design;
 using NuGet;
 
@@ -34,5 +35,16 @@ namespace PackageManagement.Tests.Helpers
 				return base.ActiveRepository;
 			}
 		}
+		
+		public Exception ExeptionToThrowWhenRecentPackageRepositoryAccessed { get; set; }
+		
+		public override IRecentPackageRepository RecentPackageRepository {
+			get {
+				if (ExeptionToThrowWhenRecentPackageRepositoryAccessed != null) {
+					throw ExeptionToThrowWhenRecentPackageRepositoryAccessed;
+				}
+				return base.RecentPackageRepository;
+			}
+		}
 	}
 }

src/AddIns/Misc/PackageManagement/Test/Src/RecentPackagesViewModelTests.cs

@@ -34,7 +34,12 @@ namespace PackageManagement.Tests
 		
 		void CreateViewModel()
 		{
-			registeredPackageRepositories = new FakeRegisteredPackageRepositories();
+			CreateViewModel(new FakeRegisteredPackageRepositories());
+		}
+		
+		void CreateViewModel(FakeRegisteredPackageRepositories registeredPackageRepositories)
+		{
+			this.registeredPackageRepositories = registeredPackageRepositories;
 			taskFactory = new FakeTaskFactory();
 			var packageViewModelFactory = new FakePackageViewModelFactory();
 			packageManagementEvents = new PackageManagementEvents();
@@ -133,5 +138,19 @@ namespace PackageManagement.Tests
 			
 			Assert.AreEqual(0, viewModel.PackageViewModels.Count);
 		}
+		
+		[Test]
+		public void ReadPackages_ExceptionThrownWhenAccessingActiveRepository_ErrorMessageFromExceptionNotOverriddenByReadPackagesCall()
+		{
+			var registeredRepositories = new ExceptionThrowingRegisteredPackageRepositories();
+			registeredRepositories.ExeptionToThrowWhenRecentPackageRepositoryAccessed = 
+				new Exception("Test");
+			CreateViewModel(registeredRepositories);
+			
+			viewModel.ReadPackages();
+			
+			ApplicationException ex = Assert.Throws<ApplicationException>(CompleteReadPackagesTask);
+			Assert.AreEqual("Test", ex.Message);
+		}
 	}
 }

src/AddIns/Misc/PackageManagement/Test/Src/RegisteredPackageRepositoriesTests.cs

@@ -330,5 +330,18 @@ namespace PackageManagement.Tests
 			
 			Assert.AreEqual(expectedPackageSource, activePackageSource);
 		}
+		
+		[Test]
+		public void ActiveRepository_NullInOptionsAndNoEnabledPackageSources_ThrowsNoPackageSourcesConfiguredException()
+		{
+			CreateRegisteredPackageRepositories();
+			packageSourcesHelper.Options.ActivePackageSource = null;
+			registeredRepositories.PackageSources.Clear();
+			registeredRepositories.PackageSources.Add(new PackageSource("source") { IsEnabled = false });
+			
+			Assert.Throws<NoPackageSourcesConfiguredException>(() => {
+				IPackageRepository repository = registeredRepositories.ActiveRepository;
+			});
+		}
 	}
 }