[xbuild]: Check a <Target>'s "Returns" first, then fall-back to "Outputs".

This fixes a problem with the "Microsoft.Bcl.Build" NuGet package, which
overrides the "GetTargetPath" target in a custom .targets file and uses
"Returns" instead of "Outputs".

3 files changed, 40 insertions, 3 deletions

diff --git a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Target.cs b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Target.cs
index d0011305399..630cb4a46e1 100644
--- a/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Target.cs
+++ b/mcs/class/Microsoft.Build.Engine/Microsoft.Build.BuildEngine/Target.cs
@@ -411,9 +411,12 @@ namespace Microsoft.Build.BuildEngine {
 
 		ITaskItem [] OutputsAsITaskItems {
 			get {
-				string outputs = targetElement.GetAttribute ("Outputs");
-				if (outputs == String.Empty)
-					return new ITaskItem [0];
+				var outputs = targetElement.GetAttribute ("Returns");
+				if (string.IsNullOrEmpty (outputs)) {
+					outputs = targetElement.GetAttribute ("Outputs");
+					if (string.IsNullOrEmpty (outputs))
+						return new ITaskItem [0];
+				}
 
 				Expression e = new Expression ();
 				e.Parse (outputs, ParseOptions.AllowItemsNoMetadataAndSplit);
diff --git a/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs b/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
index bc09d366de5..faa959fae4e 100644
--- a/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
+++ b/mcs/class/Microsoft.Build.Engine/Test/Microsoft.Build.BuildEngine/TargetTest.cs
@@ -963,5 +963,26 @@ namespace MonoTests.Microsoft.Build.BuildEngine {
 		}
 #endif
 
+		[Test]
+		public void TestTargetReturns ()
+		{
+			engine = new Engine (Consts.BinPath);
+			project = engine.CreateNewProject ();
+			project.Load (Path.Combine ("Test", "resources", "TestReturns.csproj"));
+
+			var logger = new TestMessageLogger ();
+			engine.RegisterLogger (logger);
+
+			bool result = project.Build ("Main");
+			if (!result) {
+				logger.DumpMessages ();
+				Assert.Fail ("Build failed");
+			}
+
+			logger.CheckLoggedMessageHead ("Result: Bar", "A1");
+
+			Assert.AreEqual (0, logger.NormalMessageCount, "Unexpected extra messages found");
+		}
+
 	}
 }
diff --git a/mcs/class/Microsoft.Build.Engine/Test/resources/TestReturns.csproj b/mcs/class/Microsoft.Build.Engine/Test/resources/TestReturns.csproj
new file mode 100644
index 00000000000..a71ea5db7e2
--- /dev/null
+++ b/mcs/class/Microsoft.Build.Engine/Test/resources/TestReturns.csproj
@@ -0,0 +1,13 @@
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
+
+	<Target Name="GetFoo" Outputs="Out" Returns="Bar" />
+
+	<Target Name="Main">
+		<MSBuild Projects="TestReturns.csproj" Targets="GetFoo">
+			<Output TaskParameter="TargetOutputs" ItemName="FooResult"/>
+		</MSBuild>
+		
+		<Message Text="Result: %(FooResult.Identity)" />
+	</Target>
+
+</Project>