Add 'AspectJ_JDK_Update' hint in various places

The hint is meant to help AspectJ developers identify the places where
there are to-dos for releases supporting new Java versions. This is work
in progress, new tags can be added wherever necessary in the future. But
for now, the most important places should be covered:

 - AJC version string
 - Test infrastructure (test suites, classes and XML files)
 - BCEL class file version MAJOR_*, MINOR_* constants
 - AjcTask constants for compiler source, target, release
 - LangUtil::is*VMOrGreater methods
 - ASM and JDT Core dependency versions
 - CI workflow file
 - Release notes

The to-do to check the tagged places is also mentioned in RELEASE.md.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

.github/workflows/maven.yml

@@ -22,6 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        # AspectJ_JDK_Update
         # Check for available Temurin releases on https://adoptium.net/releases.html
         java: [ 17, 21 ]
 

bcel-builder/src/main/java/org/aspectj/apache/bcel/Constants.java

@@ -106,6 +106,7 @@ public interface Constants {
 	short MINOR_20 = 0;
 	short MAJOR_21 = 65;
 	short MINOR_21 = 0;
+	// AspectJ_JDK_Update
 //	short MAJOR_22 = 66;
 //	short MINOR_22 = 0;
 

docs/developer/RELEASE.md

@@ -73,6 +73,10 @@ manual versioning process without using Maven Release plugin. It might work usin
   - committing the snapshot POMs,
   - pushing the previous commits and the release tag to the upstream Git repository.
 
+If the AspectJ release also includes support for a new Java version, then before releasing AspectJ, search for the
+term `AspectJ_JDK_Update` across all files in the code base, also non-Java ones. Check, that you have not forgotten to
+add any necessary infrastructure or to increment version numbers as appropriate.  
+
 In order to show the details and give you more control over the process, you can do it step by step as follows:
 
 ```shell

docs/release/README-1.9.21.adoc

@@ -2,6 +2,9 @@
 :doctype: book
 :leveloffset: +1
 
+// AspectJ_JDK_Update: Each a.b.c release needs a new release notes document. For a.b.c.d minors, the existing a.b.c
+// document can be updated. After copying this document, remove the comment from the previous one.
+
 The releases 1.9.21 and 1.9.21.1 are described together in this document.
 
 = AspectJ 1.9.21.1

org.aspectj.ajdt.core/src/main/resources/org/aspectj/org/eclipse/jdt/internal/compiler/batch/messages_aspectj.properties

@@ -1,4 +1,6 @@
 compiler.name = AspectJ Compiler
+# AspectJ_JDK_Update: Update not only for new Java versions, but each time JDT Core is updated with an upstream merge.
+# Always make sure to update to the latest merge commit ID and date of the latest upstream commit.
 compiler.version = Eclipse Compiler 8398f6c1210ec3 (13Feb2024) - Java21
 compiler.copyright =
 

pom.xml

@@ -27,8 +27,8 @@
 		<maven.javadoc.skip>true</maven.javadoc.skip>
 
 		<!-- Dependency versions -->
-		<jdt.core.version>1.9.21.1</jdt.core.version>
-		<asm.version>9.6</asm.version>
+		<jdt.core.version>1.9.21.1</jdt.core.version> <!-- AspectJ_JDK_Update -->
+		<asm.version>9.6</asm.version> <!-- AspectJ_JDK_Update -->
 		<lib.ant.version>1.6.3</lib.ant.version>
 		<lib.ant.xerces.version>2.6.2</lib.ant.xerces.version>
 		<lib.regexp.version>1.2</lib.regexp.version>

taskdefs/src/main/java/org/aspectj/tools/ant/taskdefs/AjcTask.java

@@ -250,14 +250,17 @@ public class AjcTask extends MatchingTask {
 
 	public static final String COMMAND_EDITOR_NAME = AjcTask.class.getName() + ".COMMAND_EDITOR";
 
+	// AspectJ_JDK_Update
 	static final String[] TARGET_INPUTS = new String[] {
 		"1.1", "1.2", "1.3", "1.4", "1.5", "1.6", "1.7", "1.8", "1.9", "9",
 		"10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21"
 	};
+	// AspectJ_JDK_Update
 	static final String[] SOURCE_INPUTS = new String[] {
 		"1.3", "1.4", "1.5", "1.6", "1.7", "1.8", "1.9", "9",
 		"10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21"
 	};
+	// AspectJ_JDK_Update
 	static final String[] COMPLIANCE_INPUTS = new String[] {
 		"-1.3", "-1.4", "-1.5", "-1.6", "-1.7", "-1.8", "-1.9", "-9",
 		"-10", "-11", "-12", "-13", "-14", "-15", "-16", "-17", "-18", "-19", "-20", "-21"

testing/src/test/java/org/aspectj/testing/XMLBasedAjcTestCaseForJava21Only.java

@@ -19,6 +19,7 @@ public abstract class XMLBasedAjcTestCaseForJava21Only extends XMLBasedAjcTestCa
 
 	@Override
 	public void setUp() throws Exception {
+		// AspectJ_JDK_Update
 		// Activate this block after upgrading to JDT Core Java 22
 		/*
 		throw new IllegalStateException(
@@ -27,6 +28,7 @@ public abstract class XMLBasedAjcTestCaseForJava21Only extends XMLBasedAjcTestCa
 				"This compiler does not support preview features of a previous version anymore."
 		);
 		*/
+		// AspectJ_JDK_Update
 		// Activate this block before upgrading to JDT Core Java 22
 		if (!LangUtil.is21VMOrGreater() || LangUtil.is22VMOrGreater()) {
 			throw new IllegalStateException(

tests/src/test/java/org/aspectj/systemtest/AllTests19.java

@@ -43,6 +43,7 @@ public class AllTests19 {
 		suite.addTest(AllTestsAspectJ199.suite());
 		suite.addTest(AllTestsAspectJ1919.suite());
 		suite.addTest(AllTestsAspectJ1920.suite());
+		// AspectJ_JDK_Update
 		suite.addTest(AllTestsAspectJ1921.suite());
 		suite.addTest(AllTests18.suite());
 		// $JUnit-END$

tests/src/test/java/org/aspectj/systemtest/ajc1921/AllTestsAspectJ1921.java

@@ -11,6 +11,18 @@ import junit.framework.Test;
 import junit.framework.TestSuite;
 import org.aspectj.util.LangUtil;
 
+// AspectJ_JDK_Update
+//  - Copy 'ajc*' package with all classes to a new package, incrementing the version number in the package
+//  - Rename all classes, incrementing version numbers
+//  - Add this class to the suite in class AllTests19
+//  - Increment version numbers in strings, method calls and constants to the appropriate values, creating necessary
+//    methods and constants classes providing them, if they do not exist yet
+//  - Also increment references to 'ajc*.xml' and 'sanity-tests-*.xml' test definition, copying the previous
+//    tests/src/test/resources/org/aspectj/systemtest/ajc* directory, incrementing all names and adjusting the XML
+//    file contents appropriately
+//  - Search for other 'AspectJ_JDK_Update' hints in the repository, also performing the necessary to-dos there
+//  - Remove this comment from the previous class version after copying this one
+
 /**
  * @author Alexander Kriegisch
  */
@@ -23,6 +35,7 @@ public class AllTestsAspectJ1921 {
 			suite.addTest(SanityTestsJava21.suite());
 			suite.addTest(Ajc1921TestsJava.suite());
 		}
+		// AspectJ_JDK_Update
 		// Do not run tests using a previous compiler's preview features anymore. They would all fail.
 		// TODO: Comment out the following block when upgrading JDT Core to Java 22
 		if (LangUtil.is21VMOrGreater() && !LangUtil.is22VMOrGreater()) {

util/src/main/java/org/aspectj/util/LangUtil.java

@@ -191,6 +191,7 @@ public class LangUtil {
 		return 21 <= vmVersion;
 	}
 
+	// AspectJ_JDK_Update
 	public static boolean is22VMOrGreater() {
 		return 22 <= vmVersion;
 	}