Build with Tycho 3.0.4 and set up Maven toolchains

General guide for Maven toolchains:
https://maven.apache.org/guides/mini/guide-using-toolchains.html
Using the Maven-Toolchain-Plugin and its 'toolchain' goal the
maven-compiler-plugin is configured to use a JDK from the toolchain that
matches the specified release version.

Configure the Tycho-Compiler-Plugin to use the JDK in the toolchain that
matches the Bundle-RequiredExecutionEnvironment:
https://tycho.eclipseprojects.io/doc/3.0.4/tycho-compiler-plugin/compile-mojo.html#useJDK

Configure the Maven-Surefire-Plugin to use a specific JDK version from
the toolchain to launch a test runtime:
https://maven.apache.org/surefire/maven-surefire-plugin/test-mojo.html#jdkToolchain

Configure the Tycho-Surefire-Plugin to use a specific JDK version from
the toolchain to launch a test runtime:
https://tycho.eclipseprojects.io/doc/3.0.4/tycho-surefire-plugin/test-mojo.html#useJDK

About the toolchains.xml generated by the setup-java Github action and
the exported JAVA_HOME_ environment variables:
- https://github.com/actions/setup-java/#install-multiple-jdks
- https://github.com/actions/setup-java/blob/main/docs/advanced-usage.md#Modifying-Maven-Toolchains

Fixes eclipse-xtext#2216

Co-authored-by: Lorenzo Bettini <[email protected]>

Jenkinsfile

@@ -28,7 +28,7 @@ pipeline {
 
   tools {
      maven "apache-maven-3.8.6"
-     jdk "${params.JDK_VERSION}"
+     jdk "temurin-jdk17-latest"
   }
 
   stages {
@@ -59,10 +59,15 @@ pipeline {
     stage('Maven/Tycho Build & Test') {
       environment {
         MAVEN_OPTS = "-Xmx1500m"
+        JAVA_HOME_11_X64 = tool(type:'jdk', name:'temurin-jdk11-latest')
+        JAVA_HOME_17_X64 = tool(type:'jdk', name:'temurin-jdk17-latest')
       }
       steps {
         xvnc(useXauthority: true) {
-          sh "./full-build.sh --tp=${selectedTargetPlatform()} ${javaVersionBasedProperties()}"
+          sh """
+            ./full-build.sh --tp=${selectedTargetPlatform()} \
+              ${javaVersion() == 17 ? '' : '--toolchains releng/toolchains.xml -Pstrict-release-jdk'}
+          """
         }
       }// END steps
     } // END stage
@@ -161,20 +166,3 @@ def selectedTargetPlatform() {
         return tp
     }
 }
-
-/**
- * Tycho 3 requires Java 17.
- * If the build uses Java version 11, we return the proper tycho-version override.
- * Otherwise, we return an empty string.
- */
-def javaVersionBasedProperties() {
-    def javaVersion = javaVersion()
-
-    if (javaVersion<17) {
-        println("Switching to Tycho 2.7.5 with Java ${javaVersion}")
-        return '-Dtycho-version=2.7.5'
-    } else {
-        return ''
-    }
-}
-

pom.xml

@@ -400,6 +400,33 @@
 				</plugins>
 			</build>
 		</profile>
+		<profile>
+			<id>strict-release-jdk</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>org.apache.maven.plugins</groupId>
+						<artifactId>maven-toolchains-plugin</artifactId>
+						<version>3.1.0</version>
+						<executions>
+							<execution>
+								<goals>
+									<goal>toolchain</goal>
+								</goals>
+							</execution>
+						</executions>
+						<configuration>
+							<toolchains>
+								<jdk>
+									<!-- Toolchain selected by maven/tycho-compiler for compilation and maven/tycho-surefire as JRE of launched test-runtimes-->
+									<version>${maven.compiler.release</version>
+								</jdk>
+							</toolchains>
+						</configuration>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
 	</profiles>
 
 	<build>

releng/toolchains.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF8"?>
+<toolchains xmlns="https://maven.apache.org/TOOLCHAINS/1.1.0"
+	xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="https://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+	<toolchain>
+		<type>jdk</type>
+		<provides>
+			<id>JavaSE-11</id>
+			<version>11</version>
+		</provides>
+		<configuration>
+			<jdkHome>${env.JAVA_HOME_11_X64}</jdkHome>
+		</configuration>
+	</toolchain>
+	<toolchain>
+		<type>jdk</type>
+		<provides>
+			<id>JavaSE-17</id>
+			<version>17</version>
+		</provides>
+		<configuration>
+			<jdkHome>${env.JAVA_HOME_17_X64}</jdkHome>
+		</configuration>
+	</toolchain>
+</toolchains>