Fix Windows jvm.config parsing and add debug logging to scripts

gnodet · gnodet · commit 9de4237b627a · 2025-12-10T11:57:39.000+01:00
- mvn.cmd: Use 'cmd /c' to run JvmConfigParser in a subshell, ensuring
  file handles are properly released before reading the temp file.
  The previous 'for /f' with backticks approach did not correctly
  capture the Java output on Windows.

- mvn, mvn.cmd: Add debug logging controlled by MAVEN_DEBUG_SCRIPT
  environment variable. When set, both scripts will output detailed
  information about jvm.config parsing, including:
  - Path to jvm.config file
  - Java command and arguments
  - Parser exit code and output
  - Final MAVEN_OPTS/JVM_CONFIG_MAVEN_OPTS value
  - Full JVM command line before launching Maven

This helps diagnose jvm.config issues on CI systems where the log
files are the primary debugging tool.
diff --git a/apache-maven/src/assembly/maven/bin/JvmConfigParser.java b/apache-maven/src/assembly/maven/bin/JvmConfigParser.java
@@ -18,6 +18,7 @@
  */
 
 import java.io.IOException;
+import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -29,29 +30,53 @@
  * Parses .mvn/jvm.config file for Windows batch/Unix shell scripts.
  * This avoids the complexity of parsing special characters (pipes, quotes, etc.) in scripts.
  *
- * Usage: java JvmConfigParser.java <jvm.config-path> <maven-project-basedir>
+ * Usage: java JvmConfigParser.java <jvm.config-path> <maven-project-basedir> [output-file]
+ *
+ * If output-file is provided, writes result to that file (avoids Windows file locking issues).
+ * Otherwise, outputs to stdout.
  *
  * Outputs: Single line with space-separated quoted arguments (safe for batch scripts)
  */
 public class JvmConfigParser {
     public static void main(String[] args) {
-        if (args.length != 2) {
-            System.err.println("Usage: java JvmConfigParser.java <jvm.config-path> <maven-project-basedir>");
+        if (args.length < 2 || args.length > 3) {
+            System.err.println("Usage: java JvmConfigParser.java <jvm.config-path> <maven-project-basedir> [output-file]");
             System.exit(1);
         }
 
         Path jvmConfigPath = Paths.get(args[0]);
         String mavenProjectBasedir = args[1];
+        Path outputFile = args.length == 3 ? Paths.get(args[2]) : null;
 
         if (!Files.exists(jvmConfigPath)) {
-            // No jvm.config file - output nothing
+            // No jvm.config file - output nothing (create empty file if output specified)
+            if (outputFile != null) {
+                try {
+                    Files.writeString(outputFile, "", StandardCharsets.UTF_8);
+                } catch (IOException e) {
+                    System.err.println("ERROR: Failed to write output file: " + e.getMessage());
+                    System.err.flush();
+                    System.exit(1);
+                }
+            }
             return;
         }
 
         try {
             String result = parseJvmConfig(jvmConfigPath, mavenProjectBasedir);
-            System.out.print(result);
-            System.out.flush();
+            if (outputFile != null) {
+                // Write directly to file - this ensures proper file handle cleanup on Windows
+                // Add newline at end for Windows 'for /f' command compatibility
+                try (Writer writer = Files.newBufferedWriter(outputFile, StandardCharsets.UTF_8)) {
+                    writer.write(result);
+                    if (!result.isEmpty()) {
+                        writer.write(System.lineSeparator());
+                    }
+                }
+            } else {
+                System.out.print(result);
+                System.out.flush();
+            }
         } catch (IOException e) {
             // If jvm.config exists but can't be read, this is a configuration error
             // Print clear error and exit with error code to prevent Maven from running
diff --git a/apache-maven/src/assembly/maven/bin/mvn b/apache-maven/src/assembly/maven/bin/mvn
@@ -294,4 +294,9 @@ for arg in "$@"; do
     cmd="$cmd \"$arg\""
 done
 
+if [ -n "$MAVEN_DEBUG_SCRIPT" ]; then
+  echo "[DEBUG] Launching JVM with command:" >&2
+  echo "[DEBUG]   $cmd" >&2
+fi
+
 eval exec "$cmd"
diff --git a/apache-maven/src/assembly/maven/bin/mvn.cmd b/apache-maven/src/assembly/maven/bin/mvn.cmd
@@ -193,11 +193,11 @@ if defined MAVEN_DEBUG_SCRIPT (
   echo [DEBUG] Found .mvn\jvm.config file at: %MAVEN_PROJECTBASEDIR%\.mvn\jvm.config
   echo [DEBUG] Using temp file: %JVM_CONFIG_TEMP%
   echo [DEBUG] Running JvmConfigParser with Java: %JAVACMD%
-  echo [DEBUG] Parser arguments: "%MAVEN_HOME%\bin\JvmConfigParser.java" "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%"
+  echo [DEBUG] Parser arguments: "%MAVEN_HOME%\bin\JvmConfigParser.java" "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%" "%JVM_CONFIG_TEMP%"
 )
 
-rem Run parser in a subshell (cmd /c) to ensure file handles are released before we read
-cmd /c ""%JAVACMD%" "%MAVEN_HOME%\bin\JvmConfigParser.java" "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%" > "%JVM_CONFIG_TEMP%" 2>&1"
+rem Run parser with output file as third argument - Java writes directly to file to avoid Windows file locking issues
+"%JAVACMD%" "%MAVEN_HOME%\bin\JvmConfigParser.java" "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" "%MAVEN_PROJECTBASEDIR%" "%JVM_CONFIG_TEMP%"
 set JVM_CONFIG_EXIT=%ERRORLEVEL%
 
 if defined MAVEN_DEBUG_SCRIPT (
@@ -210,8 +210,6 @@ if %JVM_CONFIG_EXIT% neq 0 (
   echo   jvm.config path: %MAVEN_PROJECTBASEDIR%\.mvn\jvm.config 1>&2
   echo   Java command: %JAVACMD% 1>&2
   if exist "%JVM_CONFIG_TEMP%" (
-    echo   Parser output: 1>&2
-    type "%JVM_CONFIG_TEMP%" 1>&2
     del "%JVM_CONFIG_TEMP%" 2>nul
   )
   exit /b 1
@@ -272,6 +270,11 @@ for %%i in ("%MAVEN_HOME%"\boot\plexus-classworlds-*) do set LAUNCHER_JAR="%%i"
 set LAUNCHER_CLASS=org.codehaus.plexus.classworlds.launcher.Launcher
 if "%MAVEN_MAIN_CLASS%"=="" @set MAVEN_MAIN_CLASS=org.apache.maven.cling.MavenCling
 
+if defined MAVEN_DEBUG_SCRIPT (
+  echo [DEBUG] Launching JVM with command:
+  echo [DEBUG]   "%JAVACMD%" %INTERNAL_MAVEN_OPTS% %MAVEN_OPTS% %JVM_CONFIG_MAVEN_OPTS% %MAVEN_DEBUG_OPTS% --enable-native-access=ALL-UNNAMED -classpath %LAUNCHER_JAR% "-Dclassworlds.conf=%CLASSWORLDS_CONF%" "-Dmaven.home=%MAVEN_HOME%" "-Dmaven.mainClass=%MAVEN_MAIN_CLASS%" "-Dlibrary.jline.path=%MAVEN_HOME%\lib\jline-native" "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %LAUNCHER_CLASS% %MAVEN_ARGS% %*
+)
+
 "%JAVACMD%" ^
   %INTERNAL_MAVEN_OPTS% ^
   %MAVEN_OPTS% ^
diff --git a/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh10937QuotedPipesInMavenOptsTest.java b/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh10937QuotedPipesInMavenOptsTest.java
@@ -42,6 +42,8 @@ void testIt() throws Exception {
 
         Verifier verifier = newVerifier(basedir.toString());
         verifier.setEnvironmentVariable("MAVEN_OPTS", "-Dprop.maven-opts=\"foo|bar\"");
+        // Enable debug logging for launcher script to diagnose jvm.config parsing issues
+        verifier.setEnvironmentVariable("MAVEN_DEBUG_SCRIPT", "1");
         verifier.addCliArguments("validate");
         verifier.execute();
         verifier.verifyErrorFreeLog();
diff --git a/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh11363PipeSymbolsInJvmConfigTest.java b/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh11363PipeSymbolsInJvmConfigTest.java
@@ -42,6 +42,8 @@ void testPipeSymbolsInJvmConfig() throws Exception {
 
         Verifier verifier = newVerifier(basedir.toString());
         verifier.setForkJvm(true); // Use forked JVM to test .mvn/jvm.config processing
+        // Enable debug logging for launcher script to diagnose jvm.config parsing issues
+        verifier.setEnvironmentVariable("MAVEN_DEBUG_SCRIPT", "1");
         verifier.addCliArguments("validate");
         verifier.execute();
         verifier.verifyErrorFreeLog();
diff --git a/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh11485AtSignInJvmConfigTest.java b/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITgh11485AtSignInJvmConfigTest.java
@@ -40,6 +40,8 @@ public void testAtSignInJvmConfig() throws Exception {
         verifier.addCliArgument(
                 "-Dexpression.outputFile=" + new File(testDir, "target/pom.properties").getAbsolutePath());
         verifier.setForkJvm(true); // custom .mvn/jvm.config
+        // Enable debug logging for launcher script to diagnose jvm.config parsing issues
+        verifier.setEnvironmentVariable("MAVEN_DEBUG_SCRIPT", "1");
         verifier.addCliArgument("validate");
         verifier.execute();
         verifier.verifyErrorFreeLog();
diff --git a/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4559SpacesInJvmOptsTest.java b/its/core-it-suite/src/test/java/org/apache/maven/it/MavenITmng4559SpacesInJvmOptsTest.java
@@ -42,6 +42,8 @@ void testIt() throws Exception {
 
         Verifier verifier = newVerifier(basedir.toString());
         verifier.setEnvironmentVariable("MAVEN_OPTS", "-Dprop.maven-opts=\"foo bar\"");
+        // Enable debug logging for launcher script to diagnose jvm.config parsing issues
+        verifier.setEnvironmentVariable("MAVEN_DEBUG_SCRIPT", "1");
         verifier.addCliArguments("validate");
         verifier.execute();
         verifier.verifyErrorFreeLog();
