[MCOMPILER-542] rework log and conditions to run

Author: hboutemy

Diff for: src/it/MCOMPILER-542/pom.xml

@@ -48,11 +48,46 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
           <version>@project.version@</version>
-          <configuration>
-            <release>${java.specification.version}</release>
-          </configuration>
         </plugin>
       </plugins>
     </pluginManagement>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <executions>
+          <execution>
+            <id>default-compile</id>
+            <goals>
+              <goal>compile</goal>
+            </goals>
+            <configuration>
+              <release>${java.specification.version}</release>
+            </configuration>
+          </execution>
+          <execution>
+            <id>compile-release-9</id>
+            <goals>
+              <goal>compile</goal>
+            </goals>
+            <configuration>
+              <release>9</release>
+              <outputDirectory>${project.build.outputDirectory}-9</outputDirectory>
+            </configuration>
+          </execution>
+          <execution>
+            <id>compile-target</id>
+            <goals>
+              <goal>compile</goal>
+            </goals>
+            <configuration>
+              <source>${java.specification.version}</source>
+              <target>${java.specification.version}</target>
+              <outputDirectory>${project.build.outputDirectory}-target</outputDirectory>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
   </build>
 </project>

Diff for: src/it/MCOMPILER-542/verify.groovy

@@ -47,7 +47,8 @@ if (javaVersion != javaSpecVersion) { // handle the case when is the first relea
 }
 assert out.contains('// ' + javaSpecVersion) : "java specification version not found in module descriptor"
 
-// Additional validation that the checksum is always the same
+// Additional validation that the checksum is always the same: useful because constant pool reordering happens when
+// transforming bytecode, then we need to check results precisely
 def checksumMap = [
     '21': 'SHA-256 checksum ccc6515c8fc1bf4e675e205b2a5200d02545b06014b304c292eeddc68cffee8d',
     '17': 'SHA-256 checksum 102f24c71aff97210d66ef791b7d56f8a25ff8692d2c97b21682bc7170aaca9c',

Diff for: src/main/java/org/apache/maven/plugin/compiler/AbstractCompilerMojo.java

@@ -598,6 +598,16 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
 
     @Parameter(defaultValue = "false", property = "maven.compiler.showCompilationChanges")
     private boolean showCompilationChanges = false;
+
+    /**
+     * Timestamp for reproducible output archive entries, either formatted as ISO 8601
+     * <code>yyyy-MM-dd'T'HH:mm:ssXXX</code> or as an int representing seconds since the epoch (like
+     * <a href="https://reproducible-builds.org/docs/source-date-epoch/">SOURCE_DATE_EPOCH</a>).
+     * @since 3.12.0
+     */
+    @Parameter(defaultValue = "${project.build.outputTimestamp}")
+    private String outputTimestamp;
+
     /**
      * Resolves the artifacts needed.
      */
@@ -1186,7 +1196,10 @@ public void execute() throws MojoExecutionException, CompilationFailureException
             }
         }
 
-        patchJdkModuleVersion(compilerResult, sources);
+        if (outputTimestamp != null && (outputTimestamp.length() > 1 || Character.isDigit(outputTimestamp.charAt(0)))) {
+            // if Reproducible Builds mode, apply workaround
+            patchJdkModuleVersion(compilerResult, sources);
+        }
 
         if (useIncrementalCompilation) {
             if (incrementalBuildHelperRequest.getOutputDirectory().exists()) {
@@ -1811,7 +1824,7 @@ final String getImplicit() {
     }
 
     /**
-     * Patch module-info.class to set the java release version for java/jdk modules.
+     * JDK-8318913 workaround: Patch module-info.class to set the java release version for java/jdk modules.
      *
      * @param compilerResult should succeed.
      * @param sources the list of the source files to check for the "module-info.java"
@@ -1827,7 +1840,9 @@ private void patchJdkModuleVersion(CompilerResult compilerResult, Set<File> sour
                     final byte[] descriptorOriginal = Files.readAllBytes(moduleDescriptor);
                     final byte[] descriptorMod =
                             ModuleInfoTransformer.transform(descriptorOriginal, getRelease(), getLog());
-                    Files.write(moduleDescriptor, descriptorMod);
+                    if (descriptorMod != null) {
+                        Files.write(moduleDescriptor, descriptorMod);
+                    }
                 } catch (IOException ex) {
                     throw new MojoExecutionException("Error reading or writing module-info.class", ex);
                 }

Diff for: src/main/java/org/apache/maven/plugin/compiler/ModuleInfoTransformer.java

@@ -19,7 +19,9 @@
 package org.apache.maven.plugin.compiler;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import org.apache.maven.plugin.logging.Log;
 import org.objectweb.asm.ClassReader;
@@ -28,12 +30,18 @@
 import org.objectweb.asm.ModuleVisitor;
 import org.objectweb.asm.Opcodes;
 
+/**
+ * {@code module-info.class} bytecode transformer for
+ * <a href="https://issues.apache.org/jira/browse/MCOMPILER-542">MCOMPILER-542</a>:
+ * drops detailed JDK version.
+ */
 final class ModuleInfoTransformer {
 
     private ModuleInfoTransformer() {}
 
     static byte[] transform(byte[] originalBytecode, String javaVersion, Log log) {
         List<String> modulesModified = new ArrayList<>();
+        Set<String> foundVersions = new HashSet<>();
         ClassReader reader = new ClassReader(originalBytecode);
         ClassWriter writer = new ClassWriter(0);
 
@@ -45,10 +53,11 @@ public ModuleVisitor visitModule(String name, int access, String version) {
                     @Override
                     public void visitRequire(String module, int access, String version) {
                         // Check if the module name matches the java/jdk modules
-                        if (module.startsWith("java.") || module.startsWith("jdk.")) {
+                        if (version != null && (module.startsWith("java.") || module.startsWith("jdk."))) {
                             // Patch the version from the java.* and jdk.* modules
                             // with the --release N version.
                             super.visitRequire(module, access, javaVersion);
+                            foundVersions.add(version);
                             modulesModified.add(module);
                         } else {
                             // Keep the original require statement
@@ -61,7 +70,14 @@ public void visitRequire(String module, int access, String version) {
 
         reader.accept(classVisitor, 0);
 
-        log.info(String.format("Patch module-info.class %s with version %s", modulesModified, javaVersion));
+        if (modulesModified.isEmpty()) {
+            return null;
+        }
+
+        log.info(String.format(
+                "JDK-8318913 workaround: patched module-info.class requires version from %s to [%s] on %d JDK modules %s",
+                foundVersions, javaVersion, modulesModified.size(), modulesModified));
+
         return writer.toByteArray();
     }
 }