Improve error and traceback reporting.

src/core/org/luaj/vm2/LuaClosure.java

@@ -431,13 +431,9 @@ public class LuaClosure extends LuaFunction {
 				}
 			}
 		} catch ( LuaError le ) {
-			if ( p.lineinfo!=null && p.lineinfo.length>=pc )
-				le.addTracebackLine(p.source+":"+p.lineinfo[pc-1]);
 			throw le;
 		} catch ( Throwable t ) {
 			LuaError le = new LuaError(t);
-			if ( p.lineinfo!=null && p.lineinfo.length>=pc )
-				le.addTracebackLine(p.source+":"+p.lineinfo[pc-1]);
 			throw le;
 		} finally {
 			LuaThread.onReturn();

src/core/org/luaj/vm2/LuaError.java

@@ -23,6 +23,8 @@ package org.luaj.vm2;
 
 import java.util.Vector;
 
+import org.luaj.vm2.lib.DebugLib;
+
 /**
  * RuntimeException that is thrown and caught in response to a lua error. 
  * This error does not indicate any problem with the normal functioning 
@@ -34,7 +36,7 @@ public class LuaError extends RuntimeException {
 	private static final long serialVersionUID = 1L;
 	
 	private LuaValue msgvalue = null;
-	private Vector traceback = null;
+	private String traceback;
 
 	/** Run the error hook if there is one */
 	private static String errorHook(String msg) {
@@ -62,8 +64,9 @@ public class LuaError extends RuntimeException {
 	 * All errors generated from lua code should throw LuaError(String) instead. 
 	 */
 	public LuaError(Throwable cause) {
-		this( errorHook( "vm error: "+cause ) );
+		super( errorHook( addFileLine( "vm error: "+cause ) ) );
 		this.cause = cause;
+		this.traceback = DebugLib.traceback(1);
 	}
 
 	/**
@@ -73,7 +76,8 @@ public class LuaError extends RuntimeException {
 	 * @param message message to supply
 	 */
 	public LuaError(String message) {
-		super( errorHook( message ) );
+		super( errorHook( addFileLine( message ) ) );
+		this.traceback = DebugLib.traceback(1);
 	}		
 
 	/**
@@ -82,38 +86,35 @@ public class LuaError extends RuntimeException {
 	 */
 	public LuaError(String message, int level) {
 		super( errorHook( addFileLine( message, level ) ) );
+		this.traceback = DebugLib.traceback(1);
 	}	
 
-	/** Add file and line info to a message */
+	/** Add file and line info to a message at a particular level */
 	private static String addFileLine( String message, int level ) {
-		if ( message == null ) return message;
-		LuaFunction f = LuaThread.getCallstackFunction(level);
-		return f!=null? f+": "+message: message;		
+		if ( message == null ) return null;
+		if ( level == 0 ) return message;
+		String fileline = DebugLib.fileline(level-1);
+		return fileline!=null? fileline+": "+message: message;		
 	}
 
-	/** Get the message, including source line info if there is any */
-	public String getMessage() {		
-		String msg = super.getMessage();
-		return msg!=null && traceback!=null? traceback.elementAt(0)+": "+msg: msg;
+	/** Add file and line info for the nearest enclosing closure */
+	private static String addFileLine( String message ) {
+		if ( message == null ) return null;
+		String fileline = DebugLib.fileline();
+		return fileline!=null? fileline+": "+message: message;		
 	}
 	
-	/** Add a line of traceback info */
-	public void addTracebackLine( String line ) {
-		if ( traceback == null ) {
-			traceback = new Vector();
-		}
-		traceback.addElement( line );
-	}
+//	/** Get the message, including source line info if there is any */
+//	public String getMessage() {		
+//		String msg = super.getMessage();
+//		return msg!=null && traceback!=null? traceback+": "+msg: msg;
+//	}
 
 	/** Print the message and stack trace */
 	public void printStackTrace() {
 		System.out.println( toString() );
-		if ( traceback != null ) {
-			for ( int i=0,n=traceback.size(); i<n; i++ ) {
-				System.out.print("\t");
-				System.out.println(traceback.elementAt(i));
-			}
-		}
+		if ( traceback != null )
+			System.out.println( traceback );
 	}
 
 	/** 

src/core/org/luaj/vm2/LuaValue.java

@@ -351,7 +351,7 @@ public class LuaValue extends Varargs {
 				if ((!res.isnil()) || (tm = t.metatag(INDEX)).isnil())
 					return res;
 			} else if ((tm = t.metatag(INDEX)).isnil())
-				t.typerror("index");
+				t.typerror("table");
 			if (tm.isfunction())
 				return tm.call(t, key);
 			t = tm;

src/core/org/luaj/vm2/lib/DebugLib.java

@@ -190,7 +190,7 @@ public class DebugLib extends VarArgFunction {
 			int stackpos = (closure.p.code[pc] >> 6) & 0xff; 
 			return getobjname(this, stackpos);
 		}
-		public Object sourceline() {
+		public String sourceline() {
 			if ( closure == null ) return func.tojstring();
 			String s = closure.p.source.tojstring();
 			int line = currentline();
@@ -209,7 +209,7 @@ public class DebugLib extends VarArgFunction {
 			return closure.p.getlocalname(index, pc);
 		}
 		public String tojstring() {
-			return sourceline()+": in "+tracename();
+			return tracename()+" "+sourceline();
 		}
 	}
 	
@@ -605,10 +605,10 @@ public class DebugLib extends VarArgFunction {
 	static LuaValue _traceback(Varargs args) {
 		int a=1;
 		LuaThread thread = args.isthread(a)? args.checkthread(a++): LuaThread.getRunning(); 
-		String message = args.optjstring(a++, "stack traceback:");
+		String message = args.optjstring(a++, null);
 		int level = args.optint(a++,1);
-		String tb = DebugLib.traceback(thread, level);
-		return valueOf(message+"\n"+tb);
+		String tb = DebugLib.traceback(thread, level-1);
+		return valueOf(message!=null? message+"\n"+tb: tb);
 	}
 	
 	// =================== public utilities ====================
@@ -622,26 +622,59 @@ public class DebugLib extends VarArgFunction {
 	
 	/**
 	 * Get a traceback for a particular thread.
-	 * @param thread
-	 * @param level
-	 * @return
+	 * @param thread LuaThread to provide stack trace for
+	 * @param level 0-based level to start reporting on
+	 * @return String containing the stack trace.
 	 */
 	public static String traceback(LuaThread thread, int level) {
 		StringBuffer sb = new StringBuffer();
 		DebugState ds = getDebugState(thread);
-		DebugInfo di;
-		for ( int i=level, n=ds.debugCalls; i<n; i++ ) {
-			di = ds.getDebugInfo(i);
-			if ( di != null ) {
-				sb.append( "\t" );
-				sb.append( di.tojstring() );
-				if ( i<n )
-					sb.append( "\n" );
+		sb.append( "stack traceback:" );
+		DebugInfo di = ds.getDebugInfo(level);
+		if ( di != null ) {
+			sb.append( "\n\t" );
+			sb.append( di.sourceline() );
+			sb.append( " in " );
+			while ( (di = ds.getDebugInfo(++level)) != null ) {
+				sb.append( di.tracename() );
+				sb.append( "\n\t" );
+				sb.append( di.sourceline() );
+				sb.append( " in " );
 			}
+			sb.append( "main chunk" );
 		}
 		return sb.toString();
 	}
 
+
+	/**
+	 * Get file and line for the nearest calling closure.
+	 * @return String identifying the file and line of the nearest lua closure,
+	 * or the function name of the Java call if no closure is being called.
+	 */
+	public static String fileline() {
+		DebugState ds = getDebugState(LuaThread.getRunning());
+		DebugInfo di;
+		for ( int i=0, n=ds.debugCalls; i<n; i++ ) {
+			di = ds.getDebugInfo(i);
+			if ( di != null && di.func.isclosure() )
+				return di.sourceline();
+		}
+		return fileline(0);
+	}
+
+	/**
+	 * Get file and line for a particular level, even if it is a java function.
+	 * 
+	 * @param level 0-based index of level to get
+	 * @return
+	 */
+	public static String fileline(int level) {
+		DebugState ds = getDebugState(LuaThread.getRunning());
+		DebugInfo di = ds.getDebugInfo(level);
+		return di!=null? di.sourceline(): null;
+	}
+
 	// =======================================================
 	
 	static void lua_assert(boolean x) {

src/jse/lua.java

@@ -64,7 +64,7 @@ public class lua {
 	public static void main( String[] args ) throws IOException {
 
 		// new lua state
-		_G = JsePlatform.standardGlobals();
+		_G = JsePlatform.debugGlobals();
 		LuaC.install();
 		
 		// process args