[patch] enable debug

build.gradle

@@ -83,6 +83,8 @@ jar {
 	}
 	}
 
+
+
 shadowJar {
 	minimize()
 	// warning is printed about deprecation in 7.0 but if I fix this shadowjar turns into a bogus file
@@ -93,6 +95,12 @@ test {
 	useJUnitPlatform()
 }
 
+task copyTestResources(type: Copy) {
+	from "${projectDir}/examples"
+	into "${buildDir}/classes/java/test/examples"
+}
+processTestResources.dependsOn copyTestResources
+
 task createChecksum(type: Checksum) {
 	dependsOn(assembleDist)
 	files = distZip.outputs.files

readme.adoc

@@ -11,7 +11,7 @@ Then try `jbang` which gives you:
 
 * Dependency declarations using `//DEPS <gav>` for automatic dependency resolution
 * Dependency resolution caching
-* (PLANNED) Launch with debug enabled for instant debugging from your favorite IDE
+* Launch with debug enabled for instant debugging from your favorite IDE
 * (PLANNED) Generate gradle/maven file with dependencies for easy editing in your favorite IDE
 * (PLANNED) Lookup dependencies with a short-hand name, i.e. `// DEPS log4j:1.2+,picocli` for quick getting started.
 
@@ -124,6 +124,18 @@ $ ./classpath_example.java
 1 [main] INFO classpath_example  - Hello from Java!
 ```
 
+## Debugging
+
+When running `.java` scripts with `jbang` you can pass the `--debug`-flag and the script will enable debug,
+suspend the execution and wait until you connect a debugger to port 5005.
+
+```
+jbang --debug helloworld.java
+Listening for transport dt_socket at address: 5005
+```
+
+NOTE: Be sure to put a breakpoint in your IDE/debugger before you connect to make the debugger actually stop when you need it.
+
 ## FAQ
 
 [qanda]

src/main/java/dk/xam/jbang/ExitException.java

@@ -1,6 +1,17 @@
 package dk.xam.jbang;
 
-public class ExitException extends Throwable {
-    public ExitException(int status) {
-    }
+/**
+ * Used when wanting to exit app from a command.
+ */
+public class ExitException extends RuntimeException {
+
+	private final int status;
+
+	public ExitException(int status) {
+		this.status = status;
+	}
+
+	public int getStatus() {
+		return status;
+	}
 }

src/main/java/dk/xam/jbang/Main.java

@@ -13,13 +13,13 @@
 import picocli.CommandLine;
 import picocli.CommandLine.Model.CommandSpec;
 
-@Command(name="jbang", mixinStandardHelpOptions = false, versionProvider = VersionProvider.class, description = "Compiles and runs .java/.jsh scripts.")
+@Command(name = "jbang", footer = "\nCopyright: 2020 Max Rydahl Andersen, License: MIT\nWebsite: https://github.com/maxandersen/jbang", mixinStandardHelpOptions = false, versionProvider = VersionProvider.class, description = "Compiles and runs .java/.jsh scripts.")
 public class Main implements Callable<Integer> {
 
 	@Spec
 	CommandSpec spec;
 
-	@Option(names = {"-d", "--debug"}, arity = "0", description = "Launch with java debug enabled.")
+	@Option(names = {"-d", "--debug"}, description = "Launch with java debug enabled.")
 	boolean debug;
 
 	@Option(names = {"-h", "--help"}, usageHelp = true, description = "Display help/info")
@@ -28,20 +28,23 @@ public class Main implements Callable<Integer> {
 	@Option(names = {"--version"}, versionHelp = true, arity = "0", description = "Display version info")
 	boolean versionRequested;
 
-	@Parameters
-	String script;
-
-	@Parameters(arity = "1..*")
-	List<String> params;
+	@Parameters(index = "0", description = "A file with java code or if named .jsh will be run with jshell")
+	String scriptOrFile;
 
+	@Parameters(index = "1..*", arity = "0..*", description = "Parameters to pass on to the script")
+	List<String> params = new ArrayList<String>();
 
 	void info(String msg) {
 		spec.commandLine().getErr().println(msg);
 	}
 
+	void warn(String msg) {
+		info("[jbang] [WARNING] " + msg);
+	}
+
 	void quit(int status) {
 		out.println(status == 0 ? "true" : "false");
-		exit(status);
+		throw new ExitException(status);
 	}
 
 	static String USAGE = "j'bang - Enhanced scripting support for Java on *nix-based systems.\n" + "\n"
@@ -52,12 +55,15 @@ void quit(int status) {
 	private static File prepareScript;
 
 	public static void main(String... args) throws FileNotFoundException {
-		var main = new Main();
-
-		int exitcode = new CommandLine(main).setStopAtPositional(true).setOut(new PrintWriter(err, true)).setErr(new PrintWriter(err, true)).execute(args);
+		int exitcode = getCommandLine().execute(args);
 		System.exit(exitcode);
 	}
 
+	static CommandLine getCommandLine() {
+		return new CommandLine(new Main()).setExitCodeExceptionMapper(new VersionProvider()).setStopAtPositional(true)
+				.setOut(new PrintWriter(err, true)).setErr(new PrintWriter(err, true));
+	}
+
 	@Override
 	public Integer call() throws FileNotFoundException {
 
@@ -69,7 +75,15 @@ public Integer call() throws FileNotFoundException {
 			quit(0);
 		}
 
-		prepareScript = prepareScript(script);
+		String cmdline = generateCommandLine();
+
+		out.println(cmdline);
+
+		return 0;
+	}
+
+	String generateCommandLine() throws FileNotFoundException {
+		prepareScript = prepareScript(scriptOrFile);
 
 		Scanner sc = new Scanner(prepareScript);
 		sc.useDelimiter("\\Z");
@@ -79,32 +93,35 @@ public Integer call() throws FileNotFoundException {
 		List<String> dependencies = script.collectDependencies();
 
 		var classpath = new DependencyUtil().resolveDependencies(dependencies, Collections.emptyList(), true);
-		StringBuffer optionalArgs = new StringBuffer(" ");
+		List<String> optionalArgs = new ArrayList<String>();
 
 		var javacmd = "java";
-		var sourceargs = " --source 11";
 		if (prepareScript.getName().endsWith(".jsh")) {
 			javacmd = "jshell";
-			sourceargs = "";
 			if (!classpath.isBlank()) {
-				optionalArgs.append("--class-path " + classpath);
+				optionalArgs.add("--class-path " + classpath);
+			}
+			if (debug) {
+				info("debug not possible when running via jshell.");
 			}
 
 		} else {
-			// optionalArgs.append("
-			// -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005");
+			optionalArgs.add("--source 11");
+			if (debug) {
+				optionalArgs.add("-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005");
+			}
 			if (!classpath.isBlank()) {
-				optionalArgs.append("-classpath " + classpath);
+				optionalArgs.add("-classpath " + classpath);
 			}
 		}
 
-		var cmdline = new StringBuffer(javacmd).append(optionalArgs).append(sourceargs)
-				.append(" " + getenv("JBANG_FILE"))
-				.append(" " + params.stream().skip(1).collect(Collectors.joining(" ")));
+		List<String> fullArgs = new ArrayList<>();
+		fullArgs.add(javacmd);
+		fullArgs.addAll(optionalArgs);
+		fullArgs.add(scriptOrFile);
+		fullArgs.addAll(params);
 
-		out.println(cmdline);
-
-		return 0;
+		return fullArgs.stream().collect(Collectors.joining(" "));
 	}
 
 	/**
@@ -201,5 +218,4 @@ private static File prepareScript(String scriptresouce) {
 		return scriptFile;
 	}
 
-
 }

src/main/java/dk/xam/jbang/Util.java

@@ -20,7 +20,7 @@ static public void errorMsg(String msg) {
 
 	static public void quit(int status) {
 		System.out.print(status > 0 ? "true" : "false");
-		System.exit(status);
+		throw new ExitException(status);
 	}
 
 }

src/main/java/dk/xam/jbang/VersionProvider.java

@@ -2,9 +2,17 @@
 
 import picocli.CommandLine;
 
-public class VersionProvider implements CommandLine.IVersionProvider {
+public class VersionProvider implements CommandLine.IVersionProvider, CommandLine.IExitCodeExceptionMapper {
 	@Override
 	public String[] getVersion() throws Exception {
 		return new String[]{dk.xam.jbang.BuildConfig.VERSION};
 	}
+
+	@Override
+	public int getExitCode(Throwable t) {
+		if (t instanceof ExitException) {
+			return ((ExitException) t).getStatus();
+		}
+		return CommandLine.ExitCode.SOFTWARE;
+	}
 }

src/test/java/dk/xam/jbang/TestArguments.java

@@ -1,47 +1,78 @@
 package dk.xam.jbang;
 
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+import java.util.Arrays;
+
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import picocli.CommandLine;
 
-import static org.junit.jupiter.api.Assertions.*;
-import static org.hamcrest.Matchers.*;
-import static org.hamcrest.MatcherAssert.assertThat;
-
 class TestArguments {
 
+	private CommandLine cli;
+	private Main main;
+
+	@BeforeEach
+	void setup() {
+		cli = Main.getCommandLine();
+		main = cli.getCommand();
+	}
+
 	@Test
 	public void testBasicArguments() {
-		var arg = new Main();
-		new CommandLine(arg).parseArgs("-h", "--debug", "myfile.java");
+		cli.parseArgs("-h", "--debug", "myfile.java");
 
-		assert arg.helpRequested;
-		assert arg.debug;
-		assertEquals(1, arg.params.size());
+		assert main.helpRequested;
+		assertThat(main.debug, is(true));
+		assertThat(main.scriptOrFile, is("myfile.java"));
+		assertThat(main.params.size(), is(0));
 
 	}
 
 	@Test
-	public void testArgumentsForJbang() {
-
-		var a = Main.argsForJbang("test.java");
-		assertThat(a, is(new String[] {"test.java"}));
-
-		a = Main.argsForJbang("--debug", "test.java");
-		assertThat(a, is(new String[]{"--debug", "--", "test.java"}));
+	public void testDoubleDebug() {
+		cli.parseArgs("--debug", "test.java", "--debug", "wonka");
+		assertThat(main.debug, is(true));
+		assertThat(main.scriptOrFile, is("test.java"));
+		assertThat(main.params, is(Arrays.asList("--debug", "wonka")));
+	}
 
-		a = Main.argsForJbang("test.java", "-h");
-		assertThat(a, is(new String[]{"test.java", "-h"}));
+	/**
+	 * @Test public void testInit() { cli.parseArgs("--init", "x.java", "y.java");
+	 *       assertThat(main.script, is("x.java")); assertThat(main.params,
+	 *       is(Arrays.asList("x.java", "y.java"))); }
+	 **/
 
-		a = Main.argsForJbang("-", "--help");
-		assertThat(a, is(new String[]{"-", "--help"}));
+	@Test
+	public void testStdInWithHelpParam() {
+		cli.parseArgs("-", "--help");
+		assertThat(main.scriptOrFile, is("-"));
+		assertThat(main.helpRequested, is(false));
+		assertThat(main.params, is(Arrays.asList("--help")));
+	}
 
-		a = Main.argsForJbang("--init", "x.java", "y.java");
-		assertThat(a, is(new String[]{"--init", "--", "x.java", "y.java"}));
+	@Test
+	public void testScriptWithHelpParam() {
+		cli.parseArgs("test.java", "-h");
+		assertThat(main.scriptOrFile, is("test.java"));
+		assertThat(main.helpRequested, is(false));
+		assertThat(main.params, is(Arrays.asList("-h")));
+	}
 
-		a = Main.argsForJbang("--debug", "test.java", "--debug", "wonka");
-		assertThat(a, is(new String[]{"--debug", "--", "test.java", "--debug", "wonka"}));
+	@Test
+	public void testDebugWithScript() {
+		cli.parseArgs("--debug", "test.java");
+		assertThat(main.scriptOrFile, is("test.java"));
+		assertThat(main.debug, is(true));
+	}
 
+	@Test
+	public void testSimpleScript() {
+		cli.parseArgs("test.java");
+		assertThat(main.scriptOrFile, is("test.java"));
 	}
 
 }