[Xamarin.Android.Build.Tasks] merge two targets to fix AndroidX.Migra…

…tion (#4151)

Context: https://github.com/xamarin/XamarinAndroidXMigration
Fixes: #4068

Developers have been reporting an error when using AndroidX.Migration:

    The "CopyGeneratedJavaResourceClasses" task was not given a value for the required parameter "SourceTopDirectory".

It is reported another build fixes the issue, and it "randomly"
happens on incremental builds.

The error seems to indicate either `$(AaptTemporaryDirectory)` or
`$(ResgenTemporaryDirectory)` are blank? But it only happens when
using the AndroidX.Migration NuGet package.

From a user's build log:

    Skipping target "_PrepareCreateBaseApk" because all output files are up-to-date with respect to the input files.

Which would indicate in the case of AndroidX.Migration:

* `_PrepareCreateBaseApk` was skipped.
* `_AndroidXJetifyManifest` was injected, it came along and modified
  `$(IntermediateOutputPath)android\AndroidManifest.xml`.
* `_CreateBaseApk` ran (with updated inputs), and
  `$(AaptTemporaryDirectory)` is blank!

I could reproduce the problem in a test:

* Build a project with AndroidX.Migration
* Change C# code (a non-Java.Lang.Object class)
* Build the project again

Reviewing the MSBuild targets: `_PrepareCreateBaseApk` and
`_CreateBaseApk`. They define a property that is passed between two
targets. The following sets of targets have nearly identical
`Input`/`Output`:

* `_PrepareCreateBaseApk` and `_CreateBaseApk`
* `_PrepareUpdateAndroidResgen` and `_UpdateAndroidResgen`

This was done to workaround a long-lived bug in MSBuild:

dotnet/msbuild#1006

A fix that doesn't seem break anything is to just run
`_PrepareCreateBaseApk` *after* `$(AfterGenerateAndroidManifest)`. So
if something triggers `_CreateBaseApk`, `_PrepareCreateBaseApk` will
always run as well.

I wrote a test for this scenario, and updated the AndroidX NuGets in
our tests to use the RC now.

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/BuildTest.cs

@@ -242,6 +242,7 @@ public void AndroidXMigration ([Values (true, false)] bool isRelease)
 			proj.PackageReferences.Add (KnownPackages.AndroidXBrowser);
 			proj.PackageReferences.Add (KnownPackages.AndroidXMediaRouter);
 			proj.PackageReferences.Add (KnownPackages.AndroidXLegacySupportV4);
+			proj.PackageReferences.Add (KnownPackages.AndroidXLifecycleLiveData);
 			proj.PackageReferences.Add (KnownPackages.XamarinGoogleAndroidMaterial);
 
 			using (var b = CreateApkBuilder (Path.Combine ("temp", TestName))) {

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/IncrementalBuildTest.cs

@@ -1078,5 +1078,29 @@ public void AndroidResourceChange ()
 				}
 			}
 		}
+
+		[Test]
+		[NonParallelizable]
+		public void AndroidXMigrationBug ()
+		{
+			var proj = new XamarinFormsAndroidApplicationProject ();
+			proj.PackageReferences.Add (KnownPackages.AndroidXMigration);
+			proj.PackageReferences.Add (KnownPackages.AndroidXAppCompat);
+			proj.PackageReferences.Add (KnownPackages.AndroidXBrowser);
+			proj.PackageReferences.Add (KnownPackages.AndroidXMediaRouter);
+			proj.PackageReferences.Add (KnownPackages.AndroidXLegacySupportV4);
+			proj.PackageReferences.Add (KnownPackages.AndroidXLifecycleLiveData);
+			proj.PackageReferences.Add (KnownPackages.XamarinGoogleAndroidMaterial);
+
+			string source = "class Foo { }";
+			proj.Sources.Add (new BuildItem.Source ("Foo.cs") { TextContent = () => source });
+
+			using (var b = CreateApkBuilder ()) {
+				Assert.IsTrue (b.Build (proj), "first build should have succeeded.");
+				source = source.Replace ("Foo", "Bar");
+				proj.Touch ("Foo.cs");
+				Assert.IsTrue (b.Build (proj, doNotCleanupOnUpdate: true), "second build should have succeeded.");
+			}
+		}
 	}
 }

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Android/KnownPackages.cs

@@ -223,51 +223,61 @@ public static class KnownPackages
 		};
 		public static Package AndroidXMigration = new Package {
 			Id = "Xamarin.AndroidX.Migration",
-			Version = "1.0.0-preview04",
+			Version = "1.0.0-rc1",
 			TargetFramework = "MonoAndroid10",
 		};
 		public static Package AndroidXAppCompat = new Package {
 			Id = "Xamarin.AndroidX.AppCompat",
-			Version = "1.0.2-preview02",
+			Version = "1.1.0-rc1",
 			TargetFramework = "MonoAndroid10",
 		};
 		public static Package AndroidXBrowser = new Package {
 			Id = "Xamarin.AndroidX.Browser",
-			Version = "1.0.0-preview02",
+			Version = "1.0.0-rc1",
 			TargetFramework = "MonoAndroid90",
 			References =  {
 				new BuildItem.Reference ("Xamarin.AndroidX.Browser") {
-					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.Browser.1.0.0-preview02\\lib\\MonoAndroid90\\Xamarin.AndroidX.Browser.dll"
+					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.Browser.1.0.0-rc1\\lib\\MonoAndroid90\\Xamarin.AndroidX.Browser.dll"
 				},
 			}
 		};
 		public static Package AndroidXMediaRouter = new Package {
 			Id = "Xamarin.AndroidX.MediaRouter",
-			Version = "1.0.0-preview02",
+			Version = "1.1.0-rc1",
 			TargetFramework = "MonoAndroid90",
 			References =  {
 				new BuildItem.Reference ("Xamarin.AndroidX.MediaRouter") {
-					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.MediaRouter.1.0.0-preview02\\lib\\MonoAndroid90\\Xamarin.AndroidX.MediaRouter.dll"
+					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.MediaRouter.1.1.0-rc1\\lib\\MonoAndroid90\\Xamarin.AndroidX.MediaRouter.dll"
 				},
 			}
 		};
 		public static Package AndroidXLegacySupportV4 = new Package {
 			Id = "Xamarin.AndroidX.Legacy.Support.V4",
-			Version = "1.0.0-preview02",
+			Version = "1.0.0-rc1",
 			TargetFramework = "MonoAndroid90",
 			References =  {
 				new BuildItem.Reference ("Xamarin.AndroidX.Legacy.Support.V4") {
-					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.Legacy.Support.V4.1.0.0-preview02\\lib\\MonoAndroid90\\Xamarin.AndroidX.Legacy.Support.V4.dll"
+					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.Legacy.Support.V4.1.0.0-rc1\\lib\\MonoAndroid90\\Xamarin.AndroidX.Legacy.Support.V4.dll"
+				},
+			}
+		};
+		public static Package AndroidXLifecycleLiveData = new Package {
+			Id = "Xamarin.AndroidX.Lifecycle.LiveData",
+			Version = "2.1.0-rc1",
+			TargetFramework = "MonoAndroid90",
+			References =  {
+				new BuildItem.Reference ("Xamarin.AndroidX.Lifecycle.LiveData") {
+					MetadataValues = "HintPath=..\\packages\\Xamarin.AndroidX.Lifecycle.LiveData.2.1.0-rc1\\lib\\MonoAndroid90\\Xamarin.AndroidX.Lifecycle.LiveData.dll"
 				},
 			}
 		};
 		public static Package XamarinGoogleAndroidMaterial = new Package {
 			Id = "Xamarin.Google.Android.Material",
-			Version = "1.0.0-preview02",
+			Version = "1.0.0-rc1",
 			TargetFramework = "MonoAndroid90",
 			References =  {
 				new BuildItem.Reference ("Xamarin.Google.Android.Material") {
-					MetadataValues = "HintPath=..\\packages\\Xamarin.Google.Android.Material.1.0.0-preview02\\lib\\MonoAndroid90\\Xamarin.Google.Android.Material.dll"
+					MetadataValues = "HintPath=..\\packages\\Xamarin.Google.Android.Material.1.0.0-rc1\\lib\\MonoAndroid90\\Xamarin.Google.Android.Material.dll"
 				},
 			}
 		};

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -2265,7 +2265,6 @@ because xbuild doesn't support framework reference assemblies.
 		_CheckDuplicateJavaLibraries;
 		UpdateAndroidAssets;
 		$(_AfterCreateBaseApkDependsOnTargets);
-		_PrepareCreateBaseApk;
 	</_CreateBaseApkDependsOnTargets>
 	<_CreateBaseApkInputs>
 		$(MSBuildAllProjects)
@@ -2279,7 +2278,7 @@ because xbuild doesn't support framework reference assemblies.
 </PropertyGroup>
 
 <Target Name="_CreateBaseApk"
-  DependsOnTargets="$(_CreateBaseApkDependsOnTargets);$(AfterGenerateAndroidManifest)"
+  DependsOnTargets="$(_CreateBaseApkDependsOnTargets);$(AfterGenerateAndroidManifest);_PrepareCreateBaseApk"
   Inputs="$(_CreateBaseApkInputs)"
   Outputs="$(_PackagedResources)">