Fix Java 8 support

EMF has open version ranges pulling in whatever the latest core runtime
version is, thereby breaking Java 8 compatibility. This change fixes those
versions back up. For newer Xtext/Gradle versions it uses the Xtext BOM.
For older versions it does some hand-picked version fixes.

To test this properly, we're now not just testing against  different Gradle versions.
I've also raised the maximum versions to the latest ones that we can support without
major test rewrites.

Fixes #187
Fixes #189

gradle.properties

@@ -1,6 +1,8 @@
 minimumXtextVersion = 2.9.0
 #We can't use 2.11 while we still want Java 6 support
 bootstrapXtextVersion = 2.9.1
-latestXtextVersion = 2.14.0
+latestXtextVersion = 2.25.0
+minimumGradleVersion = 4.3
+latestGradleVersion = 6.9.1
 systemProp.http.connectionTimeout=120000
 systemProp.http.socketTimeout=120000

xtext-gradle-builder/src/main/java/org/xtext/gradle/builder/InstallDebugInfoRequest.xtend

@@ -5,7 +5,6 @@ import java.util.Collection
 import java.util.Map
 import org.eclipse.emf.ecore.resource.ResourceSet
 import org.eclipse.xtend.lib.annotations.Accessors
-import org.gradle.api.file.FileCollection
 
 //TODO move to Xtext
 @Accessors

xtext-gradle-plugin/build.gradle

@@ -93,12 +93,14 @@ tasks.withType(Test) {
 minimumIntegrationTest {
 	reports.html.destination = file("$testReportDir/$name")
 	reports.junitXml.destination = file("$testResultsDir/$name")
+	systemProperty 'gradle.version', minimumGradleVersion
 	systemProperty 'xtext.version', minimumXtextVersion
 }
 
 task latestIntegrationTest(type: Test) {
 	classpath = minimumIntegrationTest.classpath
 	testClassesDirs = minimumIntegrationTest.testClassesDirs
+	systemProperty 'gradle.version', latestGradleVersion
 	systemProperty 'xtext.version', latestXtextVersion
 	enabled = JavaVersion.current().java8Compatible
 }

xtext-gradle-plugin/src/integTest/java/org/xtext/gradle/test/AbstractIntegrationTest.xtend

@@ -5,12 +5,12 @@ import org.gradle.testkit.runner.BuildTask
 import org.junit.Before
 import org.junit.Rule
 import org.xtext.gradle.test.GradleBuildTester.ProjectUnderTest
+import java.io.File
 
 abstract class AbstractIntegrationTest {
 
 	@Rule public extension GradleBuildTester tester = new GradleBuildTester
 	protected extension ProjectUnderTest rootProject
-	protected val extension XtextBuilderAssertions = new XtextBuilderAssertions
 
 	public final static String XTEXT_VERSION = System.getProperty("xtext.version", "2.9.0")
 
@@ -25,6 +25,7 @@ abstract class AbstractIntegrationTest {
 				«repositories»
 			}
 		'''
+		createFile('gradle.properties', 'org.gradle.jvmargs=-XX:MaxMetaspaceSize=512m')
 	}
 
 	protected def CharSequence getRepositories() '''
@@ -42,4 +43,8 @@ abstract class AbstractIntegrationTest {
 		return buildResult.task(taskName)
 	}
 
+	def OutputSnapshot snapshot(File baseDir) {
+		new OutputSnapshot(baseDir)
+	}
+
 }

xtext-gradle-plugin/src/integTest/java/org/xtext/gradle/test/BuildingAMultiModulePlainLanguageProject.xtend

@@ -2,7 +2,9 @@ package org.xtext.gradle.test
 
 import org.junit.Test
 import org.xtext.gradle.test.GradleBuildTester.ProjectUnderTest
+
 import static org.junit.Assert.*
+
 //TODO use a different language than Xtend
 class BuildingAMultiModulePlainLanguageProject extends AbstractIntegrationTest {
 
@@ -15,12 +17,12 @@ class BuildingAMultiModulePlainLanguageProject extends AbstractIntegrationTest {
 			subprojects {
 				apply plugin: 'org.xtext.builder'
 				apply plugin: 'java-base'
-				
+
 				dependencies {
 					add('default', 'org.eclipse.xtend:org.eclipse.xtend.lib:«XTEXT_VERSION»')
 					xtextLanguages 'org.eclipse.xtend:org.eclipse.xtend.core:«XTEXT_VERSION»'
 				}
-				
+
 				xtext {
 					version = '«XTEXT_VERSION»'
 					languages {
@@ -34,13 +36,13 @@ class BuildingAMultiModulePlainLanguageProject extends AbstractIntegrationTest {
 						}
 					}
 				}
-				
+
 				generateXtext.classpath = configurations.'default'
-				
+
 				task jar(type:Jar) {
 					from(xtext.sourceSets.main.files)
 				}
-				
+
 				artifacts {
 					'default' jar
 				}
@@ -61,7 +63,7 @@ class BuildingAMultiModulePlainLanguageProject extends AbstractIntegrationTest {
 		downStreamProject.createFile("src/main/java/B.xtend", '''class B extends A {}''')
 		build("generateXtext")
 	}
-	
+
 	@Test
 	def void generatorOnlyRunsForLocalModels() {
 		upStreamProject.createFile("src/main/java/A.xtend", '''class A {}''')
@@ -74,13 +76,14 @@ class BuildingAMultiModulePlainLanguageProject extends AbstractIntegrationTest {
 	@Test
 	def void upStreamChangesArePickedUpDownStream() {
 		val upStream = upStreamProject.createFile("src/main/java/A.xtend", '''class A {}''')
-		val downStream = downStreamProject.createFile("src/main/java/B.xtend", '''class B extends A {}''')
+		downStreamProject.createFile("src/main/java/B.xtend", '''class B extends A {}''')
 		build("generateXtext")
+		val snapshot = snapshot(downStreamProject.projectDir)
 
 		upStream.content = '''
 			class A implements Cloneable {}
 		'''
-		val result = build("generateXtext", "-i")
-		result.hasRunGeneratorFor(downStream)
+		build("generateXtext", "-i")
+		snapshot.assertChangedClasses("B")
 	}
 }

xtext-gradle-plugin/src/integTest/java/org/xtext/gradle/test/BuildingAMultiModuleXtendProject.xtend

@@ -52,14 +52,15 @@ class BuildingAMultiModuleXtendProject extends AbstractXtendIntegrationTest {
 	@Test
 	def void upStreamChangesArePickedUpDownStream() {
 		val upStream = upStreamProject.createFile("src/main/java/A.xtend", '''class A {}''')
-		val downStream = downStreamProject.createFile("src/main/java/B.xtend", '''class B extends A {}''')
+		downStreamProject.createFile("src/main/java/B.xtend", '''class B extends A {}''')
 		build("build")
-
+        val snapshot = snapshot(downStreamProject.projectDir)
+
 		upStream.content = '''
 			class A implements Cloneable {}
 		'''
-		val result = build("build", "-i")
-		result.hasRunGeneratorFor(downStream)
+		build("build")
+		snapshot.assertChangedClasses("B")
 	}
 
 }

xtext-gradle-plugin/src/integTest/java/org/xtext/gradle/test/BuildingAPlainLanguageProject.xtend

@@ -9,16 +9,16 @@ class BuildingAPlainLanguageProject extends AbstractIntegrationTest {
 		super.setup
 		buildFile << '''
 			apply plugin: 'org.xtext.builder'
-			
+
 			configurations {
 				compile
 			}
-			
+
 			dependencies {
 				compile 'org.eclipse.xtend:org.eclipse.xtend.lib:«XTEXT_VERSION»'
 				xtextLanguages 'org.eclipse.xtend:org.eclipse.xtend.core:«XTEXT_VERSION»'
 			}
-			
+
 			xtext {
 				version = '«XTEXT_VERSION»'
 				languages {
@@ -32,7 +32,7 @@ class BuildingAPlainLanguageProject extends AbstractIntegrationTest {
 					}
 				}
 			}
-			
+
 			generateXtext.classpath = configurations.compile
 		'''
 	}
@@ -65,28 +65,27 @@ class BuildingAPlainLanguageProject extends AbstractIntegrationTest {
 		val upStream = createFile('src/main/xtend/UpStream.xtend', '''
 			class UpStream {}
 		''')
-		val downStream = createFile('src/main/xtend/DownStream.xtend', '''
+		createFile('src/main/xtend/DownStream.xtend', '''
 			class DownStream {
 				UpStream upStream
 			}
 		''')
-		val unrelated = createFile('src/main/xtend/Unrelated.xtend', '''
+		createFile('src/main/xtend/Unrelated.xtend', '''
 			class Unrelated {}
 		''')
-
 		build("generateXtext")
+		val snapshot = snapshot(projectDir)
+
 		upStream.content = '''
 			class UpStream {
 				def void foo() {}
 			}
 		'''
-		val secondResult = build("generateXtext", "-i")
-
-		secondResult.hasRunGeneratorFor(upStream)
-		secondResult.hasRunGeneratorFor(downStream)
-		secondResult.hasNotRunGeneratorFor(unrelated)
+		build("generateXtext")
+
+		snapshot.assertChangedClasses("UpStream", "DownStream")
 	}
-	
+
 	@Test
 	def void generateOnceFoldersAreNotCleanedByCleanBuilds() {
 		buildFile << '''xtext.languages.xtend.generator.outlet.cleanAutomatically = false'''
@@ -106,7 +105,7 @@ class BuildingAPlainLanguageProject extends AbstractIntegrationTest {
 		// then
 		staleFile.shouldExist
 	}
-	
+
 	@Test
 	def void generateOnceFoldersAreNotCleanedByGradleClean() {
 		buildFile << '''xtext.languages.xtend.generator.outlet.cleanAutomatically = false'''