[mmp][mtouch] Better guard framework SDK checks (#3757)

- https://github.com/xamarin/xamarin-macios/issues/3725
- These frameworks "CoreAudioKit Metal MetalKit MetalPerformanceShaders CoreNFC DeviceCheck"
 were special cased, but that special case did do an SDK check.
- Create a helper method to share check
- Add test for MM0135

docs/website/mmp-errors.md

@@ -146,6 +146,15 @@ For more details: https://developer.apple.com/news/?id=06282017a
 
 Consider updating your application and any dependencies to 64-bit.
 
+### <a name="MM0135"/>MM0135: Did not link system framework '{0}' (referenced by assembly '{1}') because it was introduced in {2} {3}, and we're using the {2} {4} SDK.
+
+To build your application, Xamarin.Mac must link against system libraries, some of which depend upon the SDK version specified in the error message. Since you are using an older version of the SDK, invocations to those APIs may fail at runtime.
+
+The recommended way to fix this error is to upgrade Xcode to get the needed SDK. If you have multiple versions of Xcode installed or want to use an Xcode in a non-default location, make sure to set the correct Xcode location in your IDE's preferences.
+
+Alternatively, enable the managed [linker](https://docs.microsoft.com/xamarin/mac/deploy-test/linker) to remove unused APIs, including (in most cases) the new ones which require the specified library. However, this will not work if your project requires APIs introduced in a newer SDK than the one your Xcode provides.
+
+As a last-straw solution, use an older version of Xamarin.Mac that does not require these new SDKs to be present during the build process.
 
 # MM1xxx: file copy / symlinks (project related)
 

docs/website/mtouch-errors.md

@@ -673,6 +673,16 @@ When using --recursive-directories, only 1 assembly should match
 
 <!-- 0134 used by mmp -->
 
+### <a name="MT0135"/>MT0135: Did not link system framework '{0}' (referenced by assembly '{1}') because it was introduced in {2} {3}, and we're using the {2} {4} SDK.
+
+To build your application, Xamarin.iOS must link against system libraries, some of which depend upon the SDK version specified in the error message. Since you are using an older version of the SDK, invocations to those APIs may fail at runtime.
+
+The recommended way to fix this error is to upgrade Xcode to get the needed SDK. If you have multiple versions of Xcode installed or want to use an Xcode in a non-default location, make sure to set the correct Xcode location in your IDE's preferences.
+
+Alternatively, enable the managed [linker](https://docs.microsoft.com/en-us/xamarin/ios/deploy-test/linker) to remove unused APIs, including (in most cases) the new ones which require the specified library. However, this will not work if your project requires APIs introduced in a newer SDK than the one your Xcode provides.
+
+As a last-straw solution, use an older version of Xamarin.iOS that does not require these new SDKs to be present during the build process.
+
 # MT1xxx: Project related error messages
 
 ### MT10xx: Installer / mtouch

tests/common/Configuration.cs

@@ -29,6 +29,7 @@ namespace Xamarin.Tests
 		public static string xcode5_root;
 		public static string xcode6_root;
 		public static string xcode72_root;
+		public static string xcode83_root;
 #if MONOMAC
 		public static string mac_xcode_root;
 #endif
@@ -208,6 +209,7 @@ namespace Xamarin.Tests
 			xcode5_root = GetVariable ("XCODE5_DEVELOPER_ROOT", "/Applications/Xcode511.app/Contents/Developer");
 			xcode6_root = GetVariable ("XCODE6_DEVELOPER_ROOT", "/Applications/Xcode601.app/Contents/Developer");
 			xcode72_root = GetVariable ("XCODE72_DEVELOPER_ROOT", "/Applications/Xcode72.app/Contents/Developer");
+			xcode83_root = GetVariable ("XCODE83_DEVELOPER_ROOT", "/Applications/Xcode83.app/Contents/Developer");
 			include_ios = !string.IsNullOrEmpty (GetVariable ("INCLUDE_IOS", ""));
 			include_mac = !string.IsNullOrEmpty (GetVariable ("INCLUDE_MAC", ""));
 			include_tvos = !string.IsNullOrEmpty (GetVariable ("INCLUDE_TVOS", ""));

tests/mmptest/mmptest.csproj

@@ -103,6 +103,7 @@
     <Compile Include="..\..\tools\common\StringUtils.cs">
       <Link>StringUtils.cs</Link>
     </Compile>
+    <Compile Include="src\WarningTests.cs" />
     <Compile Include="src\SmokeTests.cs" />
     <Compile Include="src\RegistrarTests.cs" />
     <Compile Include="src\AssemblyReferencesTests.cs" />

tests/mmptest/src/WarningTests.cs

@@ -0,0 +1,25 @@
+using System;
+using System.IO;
+using NUnit.Framework;
+
+namespace Xamarin.MMP.Tests
+{
+	[TestFixture]
+	public class WarningTests
+	{
+		[Test]
+		public void MM0135 ()
+		{
+			var oldXcode = Xamarin.Tests.Configuration.xcode83_root;
+
+			if (!Directory.Exists (oldXcode))
+				Assert.Ignore ("This test requires Xcode 8.3 (or updated to a newer one that still warns MM0135).");
+
+			MMPTests.RunMMPTest (tmpDir => {
+				TI.UnifiedTestConfig test = new TI.UnifiedTestConfig (tmpDir);
+				var output = TI.TestUnifiedExecutable (test, environment: new string[] { "MD_APPLE_SDK_ROOT", Path.GetDirectoryName (Path.GetDirectoryName (oldXcode)) });
+				output.Messages.AssertWarningPattern (135, $"Did not link system framework");
+			});
+		}
+	}
+}

tools/common/Assembly.cs

@@ -328,6 +328,14 @@ namespace Xamarin.Bundler {
 			return linkWith;
 		}
 
+		void AddFramework (string file)
+		{
+			if (Driver.GetFrameworks (App).TryGetValue (file, out var framework) && framework.Version > App.SdkVersion)
+				ErrorHelper.Warning (135, "Did not link system framework '{0}' (referenced by assembly '{1}') because it was introduced in {2} {3}, and we're using the {2} {4} SDK.", file, FileName, App.PlatformName, framework.Version, App.SdkVersion);
+			else if (Frameworks.Add (file))
+				Driver.Log (3, "Linking with the framework {0} because it's referenced by a module reference in {1}", file, FileName);
+		}
+
 		public void ComputeLinkerFlags ()
 		{
 			foreach (var m in AssemblyDefinition.Modules) {
@@ -382,8 +390,7 @@ namespace Xamarin.Bundler {
 #if MTOUCH
 						if (!App.IsSimulatorBuild) {
 #endif
-							if (Frameworks.Add (file))
-								Driver.Log (3, "Linking with the framework {0} because it's referenced by a module reference in {1}", file, FileName);
+							AddFramework (file);
 #if MTOUCH
 						}
 #endif
@@ -415,11 +422,7 @@ namespace Xamarin.Bundler {
 						// detect frameworks
 						int f = name.IndexOf (".framework/", StringComparison.Ordinal);
 						if (f > 0) {
-							Framework framework;
-							if (Driver.GetFrameworks (App).TryGetValue (file, out framework) && framework.Version > App.SdkVersion)
-								Driver.Log (3, "Not linking with the framework {0} (referenced by a module reference in {1}) because it was introduced in {2} {3}, and we're using the {2} {4} SDK.", file, FileName, App.PlatformName, framework.Version, App.SdkVersion);
-							else if (Frameworks.Add (file))
-								Driver.Log (3, "Linking with the framework {0} because it's referenced by a module reference in {1}", file, FileName);
+							AddFramework (file);
 						} else {
 							if (UnresolvedModuleReferences == null)
 								UnresolvedModuleReferences = new HashSet<ModuleReference> ();