Require JDK 8 on CI?

XML output changed between JDK 8 and JDK 11, breaking some unit tests.

Constrain CI to using JDK 8, so that tests pass.

Additionally, *for consistency*, update `TestJVM` to look for
`JdkInfo.props`.  If found, use the `$(JdkJvmPath)` value at
`/Project/Chooose/When/PropertyGroup/JdkJvmPath` instead of using
`JdkInfo.GetKnownSystemJdkInfos()`, so that the JVM that we built
against is also used for unit test execution.

Author: jonpryor

build-tools/automation/azure-pipelines.yaml

@@ -18,6 +18,7 @@ pr:
 variables:
   RunningOnCI: true
   Build.Configuration: Release
+  MaxJdkVersion: 8
   DotNetCoreVersion: 5.0.103
   HostedMacImage: macOS-10.15
   HostedWinVS2019: Hosted Windows 2019 with VS2019
@@ -108,15 +109,15 @@ jobs:
 
   - template: templates\install-dependencies.yaml
 
-  - script: make prepare CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=11
+  - script: make prepare CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=$(MaxJdkVersion)
     displayName: make prepare
 
-  - script: make all CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=11
+  - script: make all CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=$(MaxJdkVersion)
     displayName: make all
 
   - script: |
       r=0
-      make run-all-tests CONFIGURATION=$(Build.Configuration) || r=$?
+      make run-all-tests CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=$(MaxJdkVersion) || r=$?
       jar cf xatb.jar -C tests/Xamarin.Android.Tools.Bytecode-Tests/obj/*/classes .
       zip -r bin.zip bin
       exit $r
@@ -158,7 +159,7 @@ jobs:
 
   - template: templates\install-dependencies.yaml
 
-  - script: make prepare-core CONFIGURATION=$(Build.Configuration)
+  - script: make prepare-core CONFIGURATION=$(Build.Configuration) JI_MAX_JDK=$(MaxJdkVersion)
     displayName: make prepare-core
 
   - template: templates\core-build.yaml

build-tools/automation/templates/core-build.yaml

@@ -6,7 +6,7 @@ steps:
   displayName: Prepare Solution
   inputs:
     projects: Java.Interop.sln
-    arguments: '-c $(Build.Configuration) -target:Prepare'
+    arguments: '-c $(Build.Configuration) -target:Prepare -p:MaxJdkVersion=$(MaxJdkVersion)'
 
 - task: DotNetCoreCLI@2
   displayName: Build Solution

build-tools/scripts/Prepare.targets

@@ -7,10 +7,14 @@
   <Target Name="Prepare">
     <Exec Command="git submodule update --init --recursive" WorkingDirectory="$(_TopDir)" />
     <MSBuild Projects="$(MSBuildThisFileDirectory)..\..\build-tools\Java.Interop.BootstrapTasks\Java.Interop.BootstrapTasks.csproj" />
+    <PropertyGroup>
+      <_MaxJdk>$(MaxJdkVersion)</_MaxJdk>
+      <_MaxJdk Condition=" '$(_MaxJdk)' == '' ">$(JI_MAX_JDK)</_MaxJdk>
+    </PropertyGroup>
     <JdkInfo
         JdksRoot="$(ProgramFiles)\Java"
         MakeFragmentFile="$(MSBuildThisFileDirectory)..\..\bin\Build$(Configuration)\JdkInfo.mk"
-        MaximumJdkVersion="$(JI_MAX_MDK)"
+        MaximumJdkVersion="$(_MaxJdk)"
         PropertyFile="$(_TopDir)\bin\Build$(Configuration)\JdkInfo.props">
       <Output TaskParameter="JavaHomePath" PropertyName="_JavaSdkDirectory" />
     </JdkInfo>

tests/TestJVM/TestJVM.cs

@@ -6,6 +6,7 @@
 using System.Reflection;
 using System.Threading;
 using System.Text;
+using System.Xml.Linq;
 
 using Xamarin.Android.Tools;
 
@@ -47,14 +48,47 @@ static TextWriter GetLogOutput (string envVar, string prefix, Assembly caller)
 
 		static string GetJvmLibraryPath ()
 		{
-			var env = Environment.GetEnvironmentVariable ("JI_JVM_PATH");
-			if (!string.IsNullOrEmpty (env))
-				return env;
+			var jdkDir  = ReadJavaSdkDirectoryFromJdkInfoProps ();
+			if (jdkDir != null) {
+				return jdkDir;
+			}
 			var jdk = JdkInfo.GetKnownSystemJdkInfos ()
 				.FirstOrDefault ();
 			return jdk?.JdkJvmPath;
 		}
 
+		static string ReadJavaSdkDirectoryFromJdkInfoProps ()
+		{
+			var location    = typeof (TestJVM).Assembly.Location;
+			var binDir      = Path.GetDirectoryName (Path.GetDirectoryName (location));
+			var testDir     = Path.GetFileName (Path.GetDirectoryName (location));
+			if (!testDir.StartsWith ("Test", StringComparison.OrdinalIgnoreCase)) {
+				return null;
+			}
+			var buildName   = testDir.Replace ("Test", "Build");
+			if (buildName.Contains ('-')) {
+				buildName   = buildName.Substring (0, buildName.IndexOf ('-'));
+			}
+			var jdkPropFile = Path.Combine (binDir, buildName, "JdkInfo.props");
+			if (!File.Exists (jdkPropFile)) {
+				return null;
+			}
+
+			var msbuild     = XNamespace.Get ("http://schemas.microsoft.com/developer/msbuild/2003");
+
+			var jdkProps    = XDocument.Load (jdkPropFile);
+			var jdkJvmPath  = jdkProps.Elements ()
+				.Elements (msbuild + "Choose")
+				.Elements (msbuild + "When")
+				.Elements (msbuild + "PropertyGroup")
+				.Elements (msbuild + "JdkJvmPath")
+				.FirstOrDefault ();
+			if (jdkJvmPath == null) {
+				return null;
+			}
+			return jdkJvmPath.Value;
+		}
+
 		Dictionary<string, Type> typeMappings;
 
 		public TestJVM (string[] jars = null, Dictionary<string, Type> typeMappings = null)