[XM] Fix crash in mmp when native reference path matches dllimport found

- When native_libs.Add (nr, null) was hit above and then we later matched
 we would call methods.AddRange (kvp.Value) on an empty methods

tests/common/mac/ProjectTestHelpers.cs

@@ -35,6 +35,7 @@ namespace Xamarin.MMP.Tests
 			public bool DiagnosticMSBuild { get; set; }
 			public string ProjectName { get; set; }
 			public string TestCode { get; set; }
+			public string TestDecl { get; set; }
 			public string CSProjConfig { get; set; }
 			public string References { get; set; }
 			public string AssemblyName { get; set; }
@@ -53,6 +54,7 @@ namespace Xamarin.MMP.Tests
 				TmpDir = tmpDir;
 				ProjectName = "";
 				TestCode = "";
+				TestDecl = "";
 				CSProjConfig = "";
 				References = "";
 				AssemblyName = "";
@@ -144,7 +146,7 @@ namespace Xamarin.MMP.Tests
 
 		public static string GenerateEXEProject (UnifiedTestConfig config)
 		{
-			WriteMainFile (config.TestCode, true, config.FSharp, Path.Combine (config.TmpDir, config.FSharp ? "Main.fs" : "Main.cs"));
+			WriteMainFile (config.TestDecl, config.TestCode, true, config.FSharp, Path.Combine (config.TmpDir, config.FSharp ? "Main.fs" : "Main.cs"));
 
 			string sourceDir = FindSourceDirectory ();
 			File.Copy (Path.Combine (sourceDir, "Info-Unified.plist"), Path.Combine (config.TmpDir, "Info.plist"), true);
@@ -258,7 +260,7 @@ namespace Xamarin.MMP.Tests
 
 		public static string GenerateClassicEXEProject (string tmpDir, string projectName, string testCode, string csprojConfig = "", string references = "", string assemblyName = null)
 		{
-			WriteMainFile (testCode, false, false, Path.Combine (tmpDir, "Main.cs"));
+			WriteMainFile ("", testCode, false, false, Path.Combine (tmpDir, "Main.cs"));
 
 			string sourceDir = FindSourceDirectory ();
 			File.Copy (Path.Combine (sourceDir, "Info-Classic.plist"), Path.Combine (tmpDir, "Info.plist"), true);
@@ -277,7 +279,7 @@ namespace Xamarin.MMP.Tests
 
 		public static string GenerateSystemMonoEXEProject (UnifiedTestConfig config)
 		{
-			WriteMainFile (config.TestCode, true, false, Path.Combine (config.TmpDir, "Main.cs"));
+			WriteMainFile (config.TestDecl, config.TestCode, true, false, Path.Combine (config.TmpDir, "Main.cs"));
 
 			string sourceDir = FindSourceDirectory ();
 			File.Copy (Path.Combine (sourceDir, "Info-Unified.plist"), Path.Combine (config.TmpDir, "Info.plist"), true);
@@ -325,7 +327,7 @@ namespace Xamarin.MMP.Tests
 			}
 		}
 
-		static void WriteMainFile (string content, bool isUnified, bool fsharp, string location)
+		static void WriteMainFile (string decl, string content, bool isUnified, bool fsharp, string location)
 		{
 			const string FSharpMainTemplate = @"
 namespace FSharpUnifiedExample
@@ -333,6 +335,8 @@ open System
 open AppKit
 
 module main =
+    %DECL%
+ 
     [<EntryPoint>]
     let main args =
         NSApplication.Init ()
@@ -347,6 +351,8 @@ namespace TestCase
 {
 	class MainClass
 	{
+		%DECL%
+
 		static void Main (string[] args)
 		{
 			NSApplication.Init ();
@@ -355,7 +361,7 @@ namespace TestCase
 	}
 }";
 			string currentTemplate = fsharp ? FSharpMainTemplate : MainTemplate;
-			string testCase = currentTemplate.Replace("%CODE%", content);
+			string testCase = currentTemplate.Replace ("%CODE%", content).Replace ("%DECL%", decl);
 			if (isUnified)
 				testCase = testCase.Replace ("MonoMac.", string.Empty);
 			using (StreamWriter s = new StreamWriter (location))

tests/common/mac/SimpleClass.h

@@ -1,5 +1,7 @@
 #import <Cocoa/Cocoa.h>
 
+int GetFour ();
+
 @interface SimpleClass : NSObject
 
 - (int) doIt;

tests/common/mac/SimpleClass.m

@@ -1,5 +1,10 @@
 #import "SimpleClass.h"
 
+int GetFour ()
+{
+	return 4;
+}
+
 @implementation SimpleClass
 
 - (int)doIt {

tests/mmptest/src/NativeReferencesTests.cs

@@ -145,5 +145,25 @@ namespace Xamarin.MMP.Tests
 			if (libraryName != null)
 				Assert.IsTrue (Directory.GetFiles (xm45BundlePath).Any (x => x.Contains (libraryName) == !libraryShouldNotBeCopied), string.Format ("{0} - XM45 - We did not pull in native lib: {1}", testName, libraryName));
 		}
+
+		[Test]
+		public void NativeReference_WithDllImportOfSamePath_Builds ()
+		{
+			RunMMPTest (tmpDir =>
+			{
+				string dylibPath = Path.Combine (tmpDir, "dll/");
+				string filePath = Path.Combine (dylibPath, "SimpleClassDylib.dylib");
+				Directory.CreateDirectory (dylibPath);
+				File.Copy (Path.Combine (TI.AssemblyDirectory, TI.TestDirectory + "mac-binding-project/bin/SimpleClassDylib.dylib"), filePath);
+
+				// Use absolute path here and in TestDecl to trigger bug
+				string itemGroup = string.Format ("<ItemGroup><NativeReference Include=\"{0}\"> <IsCxx>False</IsCxx><Kind>Dynamic</Kind> </NativeReference> </ItemGroup>", filePath);
+				TI.UnifiedTestConfig test = new TI.UnifiedTestConfig (tmpDir) { ProjectName = "UnifiedExample.csproj", ItemGroup = itemGroup };
+
+				test.TestDecl = string.Format ("[System.Runtime.InteropServices.DllImport (\"{0}\")]public static extern int GetFour ();", filePath);
+				test.TestCode = "GetFour ();";
+				NativeReferenceTestCore (tmpDir, test, "NativeReference_WithDllImportOfSamePath_Builds", null, true, true);
+			});
+		}
 	}
 }

tools/mmp/driver.cs

@@ -612,10 +612,16 @@ namespace Xamarin.Bundler {
 				var linked_native_libs = Link ();
 				foreach (var kvp in linked_native_libs) {
 					List<MethodDefinition> methods;
-					if (native_libs.TryGetValue (kvp.Key, out methods))
+					if (native_libs.TryGetValue (kvp.Key, out methods)) {
+						if (methods == null) {
+							methods = new List<MethodDefinition> (); 
+							native_libs [kvp.Key] = methods;
+						}
 						methods.AddRange (kvp.Value);
-					else
+					}
+					else {
 						native_libs.Add (kvp.Key, kvp.Value);
+					}
 				}
 				internalSymbols.UnionWith (BuildTarget.LinkContext.RequiredSymbols.Keys);
 				Watch (string.Format ("Linking (mode: '{0}')", App.LinkMode), 1);