[Generator] Ensure the correct error is raised when an Export is missing on a Property. (#4604)

The generator had a small bug in which we would get a NRE when a
property missed a Export attribute and had no WrapAttr. The issue is due
to the fact that an || is being used and does not shortcut when the
attribute is missing. In that case, the first Get check would pass and a
second attempt would happen with the set. In the case the set is missing,
we would get a NRE. The correct way is to ensure that we do have the get
and the set BEFORE the attr is checked.

The added test shows an example of the issue.

src/generator.cs

@@ -2300,7 +2300,12 @@ public partial class Generator : IMemberGatherer {
 					if (AttributeManager.HasAttribute<CoreImageFilterPropertyAttribute> (pi))
 						continue;
 
-					if (AttributeManager.HasAttribute<WrapAttribute> (pi.GetGetMethod ()) || AttributeManager.HasAttribute<WrapAttribute> (pi.GetSetMethod ()))
+					// Ensure there's a [Wrap] on either (or both) the getter and setter - since we already know there's no [Export]
+					var getMethod = pi.GetGetMethod ();
+					var hasWrapGet = getMethod != null && AttributeManager.HasAttribute<WrapAttribute> (getMethod);
+					var setMethod = pi.GetSetMethod ();
+					var hasWrapSet = setMethod != null && AttributeManager.HasAttribute<WrapAttribute> (setMethod);
+					if (hasWrapGet || hasWrapSet)
 						continue;
 
 					throw new BindingException (1018, true, "No [Export] attribute on property {0}.{1}", t.FullName, pi.Name);

tests/generator/ErrorTests.cs

@@ -679,5 +679,19 @@ namespace BI1063Tests {
 				bgen.AssertNoWarnings ();
 			}
 		}
+
+		[Test]
+		[TestCase (Profile.iOS)]
+		[TestCase (Profile.macOSFull)]
+		[TestCase (Profile.macOSMobile)]
+		public void MissingExportOnProperty (Profile profile)
+		{
+			var bgen = new BGenTool ();
+			bgen.Profile = profile;
+			bgen.Defines = BGenTool.GetDefaultDefines (profile);
+			bgen.CreateTemporaryBinding (File.ReadAllText (Path.Combine (Configuration.SourceRoot, "tests", "generator", "missing-export-property.cs")));
+			bgen.AssertExecuteError ("build");
+			bgen.AssertError (1018, "No [Export] attribute on property Test.NSTextInputClient.SelectedRange");
+		}
 	}
 }

tests/generator/missing-export-property.cs

@@ -0,0 +1,12 @@
+using Foundation;
+
+namespace Test
+{
+	[BaseType (typeof (NSObject))]
+	[Protocol, Model]
+	public interface NSTextInputClient
+	{
+		// missing [Export ("selectRange")] should report an error
+		NSRange SelectedRange { get; }
+	}
+}