[generator] Fix an issue with regards to attributes from inlined prot…

…ocols. Fixes #17268. (#17269)

In the following scenario:

* Type T is not available on a platform (say tvOS).
* Protocol P is available on said platform.
* A member M of P has its own availability attribute for said platform (for
  instance if P is available on tvOS 11.0, and the member is available on tvOS
  12.0).
* The protocol P is inlined into the type T.

We'd include the SupportedOSPlatform attribute from the inlined member on
generated code on other platforms (so the iOS assembly would say that the
inlined member M in T is available on tvOS).

Fixes #17268.

src/generator.cs

@@ -3699,8 +3699,12 @@ AvailabilityBaseAttribute [] GetPlatformAttributesToPrint (MemberInfo mi, Type t
 			List<AvailabilityBaseAttribute> availabilityToConsider = new List<AvailabilityBaseAttribute> ();
 			if (inlinedTypeAvailability != null) {
 				availabilityToConsider.AddRange (inlinedTypeAvailability);
+				// Don't copy parent attributes if the conflict with the type we're inlining members into
+				// Example: don't copy Introduced on top of Unavailable.
+				CopyValidAttributes (availabilityToConsider, parentContextAvailability);
+			} else {
+				availabilityToConsider.AddRange (parentContextAvailability);
 			}
-			availabilityToConsider.AddRange (parentContextAvailability);
 
 			// We do not support Watch, so strip from both our input sources before any processing
 			memberAvailability = memberAvailability.Where (x => x.Platform != PlatformName.WatchOS).ToList ();
@@ -3712,6 +3716,23 @@ AvailabilityBaseAttribute [] GetPlatformAttributesToPrint (MemberInfo mi, Type t
 			// Copy down any unavailable from the parent before expanding, since a [NoMacCatalyst] on the type trumps [iOS] on a member
 			CopyValidAttributes (memberAvailability, availabilityToConsider.Where (attr => attr.AvailabilityKind != AvailabilityKind.Introduced));
 
+			if (inlinedType is not null && inlinedType != mi.DeclaringType && memberAvailability.Count > 1) {
+				// We might have gotten conflicting availability attributes for inlined members, where the inlined member
+				// might be available on a platform the target type isn't. The target type's unavailability will come
+				// later in the list, which means that if we have an unavailable attribute after an introduced attribute,
+				// then we need to remove the introduced attribute.
+				for (var i = memberAvailability.Count - 1; i >= 0; i--) {
+					if (memberAvailability [i].AvailabilityKind != AvailabilityKind.Unavailable)
+						continue;
+					for (var k = i - 1; k >= 0; k--) {
+						if (memberAvailability [k].AvailabilityKind == AvailabilityKind.Introduced && memberAvailability [k].Platform == memberAvailability [i].Platform) {
+							memberAvailability.RemoveAt (k);
+							i--;
+						}
+					}
+				}
+			}
+
 			// Add implied catalyst\TVOS from [iOS] _before_ copying down from parent if no catalyst\TVOS attributes
 			// As those take precedent. We will do this a second time later in a moment..
 			AddImpliedPlatforms (memberAvailability);

tests/common/Configuration.cs

@@ -715,6 +715,13 @@ public static string GetBaseLibrary (Profile profile)
 			}
 		}
 
+		public static string GetBaseLibrary (ApplePlatform platform, bool isDotNet)
+		{
+			if (isDotNet)
+				return Path.Combine (GetRefDirectory (platform), GetBaseLibraryName (platform, isDotNet));
+			return GetBaseLibrary (platform.AsProfile ());
+		}
+
 		static string GetBaseLibraryName (TargetFramework targetFramework)
 		{
 			return GetBaseLibraryName (targetFramework.Platform, targetFramework.IsDotNet);

tests/common/Profile.cs

@@ -11,6 +11,7 @@ public enum Profile {
 		macOSMobile,
 		macOSFull,
 		macOSSystem,
+		MacCatalyst,
 	}
 
 	public static class ProfileExtensions {
@@ -33,5 +34,25 @@ public static ApplePlatform AsPlatform (this Profile profile)
 				throw new NotImplementedException (profile.ToString ());
 			}
 		}
+
+		public static Profile AsProfile (this ApplePlatform platform)
+		{
+			switch (platform) {
+			case ApplePlatform.iOS:
+				return Profile.iOS;
+			case ApplePlatform.MacCatalyst:
+				return Profile.MacCatalyst;
+			case ApplePlatform.MacOSX:
+				return Profile.macOSMobile;
+			case ApplePlatform.None:
+				return Profile.None;
+			case ApplePlatform.TVOS:
+				return Profile.tvOS;
+			case ApplePlatform.WatchOS:
+				return Profile.watchOS;
+			default:
+				throw new NotImplementedException (platform.ToString ());
+			}
+		}
 	}
 }

tests/generator/BGenTests.cs

@@ -1009,6 +1009,63 @@ public void CSharp10Syntax ()
 			BuildFile (Profile.iOS, "tests/csharp10syntax.cs");
 		}
 
+		[Test]
+		[TestCase (Profile.iOS)]
+#if !NET
+		[Ignore ("This only applies to .NET")]
+#endif
+		public void AttributesFromInlinedProtocols (Profile profile)
+		{
+			Configuration.IgnoreIfIgnoredPlatform (profile.AsPlatform ());
+
+			var bgen = new BGenTool ();
+			bgen.Profile = profile;
+			bgen.AddTestApiDefinition ("tests/attributes-from-inlined-protocols.cs");
+			bgen.CreateTemporaryBinding ();
+			bgen.AssertExecute ("build");
+
+			var type = bgen.ApiAssembly.MainModule.GetType ("NS", "TypeA");
+			var someMethod1 = type.Methods.Single (v => v.Name == "SomeMethod1");
+			var someMethod2 = type.Methods.Single (v => v.Name == "SomeMethod2");
+			var someMethod3 = type.Methods.Single (v => v.Name == "SomeMethod3");
+			var someMethod4 = type.Methods.Single (v => v.Name == "SomeMethod4");
+
+			var renderedSomeMethod1 = string.Join ("\n", someMethod1.CustomAttributes.Select (ca => RenderSupportedOSPlatformAttribute (ca)).OrderBy (v => v));
+			var renderedSomeMethod2 = string.Join ("\n", someMethod2.CustomAttributes.Select (ca => RenderSupportedOSPlatformAttribute (ca)).OrderBy (v => v));
+			var renderedSomeMethod3 = string.Join ("\n", someMethod3.CustomAttributes.Select (ca => RenderSupportedOSPlatformAttribute (ca)).OrderBy (v => v));
+			var renderedSomeMethod4 = string.Join ("\n", someMethod4.CustomAttributes.Select (ca => RenderSupportedOSPlatformAttribute (ca)).OrderBy (v => v));
+
+			const string expectedAttributes1 =
+@"[BindingImpl(3)]
+[Export(""someMethod1:"")]
+[SupportedOSPlatform(""ios12.0"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[UnsupportedOSPlatform(""tvos"")]";
+			const string expectedAttributes2 =
+@"[BindingImpl(3)]
+[Export(""someMethod2:"")]
+[SupportedOSPlatform(""ios12.0"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[UnsupportedOSPlatform(""tvos"")]";
+			const string expectedAttributes3 =
+@"[BindingImpl(3)]
+[Export(""someMethod3:"")]
+[SupportedOSPlatform(""ios11.0"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[UnsupportedOSPlatform(""tvos"")]";
+			const string expectedAttributes4 =
+@"[BindingImpl(3)]
+[Export(""someMethod4:"")]
+[SupportedOSPlatform(""ios11.0"")]
+[SupportedOSPlatform(""maccatalyst"")]
+[UnsupportedOSPlatform(""tvos"")]";
+
+			Assert.AreEqual (expectedAttributes1, renderedSomeMethod1, "SomeMethod1");
+			Assert.AreEqual (expectedAttributes2, renderedSomeMethod2, "SomeMethod2");
+			Assert.AreEqual (expectedAttributes3, renderedSomeMethod3, "SomeMethod3");
+			Assert.AreEqual (expectedAttributes4, renderedSomeMethod4, "SomeMethod4");
+		}
+
 		[Test]
 		public void NFloatType ()
 		{

tests/generator/BGenTool.cs

@@ -380,7 +380,11 @@ AssemblyDefinition LoadAssembly ()
 			if (assembly is null) {
 				var parameters = new ReaderParameters ();
 				var resolver = new DefaultAssemblyResolver ();
+#if NET
+				var searchdir = Path.GetDirectoryName (Configuration.GetBaseLibrary (Profile.AsPlatform (), true));
+#else
 				var searchdir = Path.GetDirectoryName (Configuration.GetBaseLibrary (Profile));
+#endif
 				resolver.AddSearchDirectory (searchdir);
 				parameters.AssemblyResolver = resolver;
 				assembly = AssemblyDefinition.ReadAssembly (Out ?? (Path.Combine (TmpDirectory, Path.GetFileNameWithoutExtension (ApiDefinitions [0]).Replace ('-', '_') + ".dll")), parameters);

tests/generator/tests/attributes-from-inlined-protocols.cs

@@ -0,0 +1,32 @@
+using System;
+
+using Foundation;
+using ObjCRuntime;
+
+namespace NS {
+	[NoTV]
+	[BaseType (typeof (NSObject))]
+	interface TypeA : ProtocolA {
+	}
+
+	[Introduced (PlatformName.iOS, 11, 0)]
+	[Introduced (PlatformName.TvOS, 11, 0)]
+	[Protocol]
+	interface ProtocolA {
+		[Introduced (PlatformName.iOS, 12, 0)]
+		[Introduced (PlatformName.TvOS, 12, 0)]
+		[Export ("someMethod1:")]
+		void SomeMethod1 (nint row);
+
+		[Introduced (PlatformName.iOS, 12, 0)]
+		[Export ("someMethod2:")]
+		void SomeMethod2 (nint row);
+
+		[Introduced (PlatformName.TvOS, 12, 0)]
+		[Export ("someMethod3:")]
+		void SomeMethod3 (nint row);
+
+		[Export ("someMethod4:")]
+		void SomeMethod4 (nint row);
+	}
+}