Allow error() function to pass any lua object including non-strings.

README.html

@@ -967,6 +967,7 @@ Files are no longer hosted at LuaForge.
 <li>Fix __len metatag processing for tables.</li>
 <li>Add fallback to __lt when pocessing __le metatag.</li>
 <li>Convert anonymous classes to inner classes (gradle build support).</li>
+<li>Allow error() function to pass any lua object including non-strings.</li>
 
 </ul></td></tr>
 </table></td></tr></table>

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

@@ -33,6 +33,10 @@ package org.luaj.vm2;
  * be thrown on almost any luaj Java operation.
  * This is analagous to the fact that any lua script can throw a lua error at any time.
  * <p> 
+ * The LuaError may be constructed with a message object, in which case the message
+ * is the string representation of that object.  getMessageObject will get the object
+ * supplied at construct time, or a LuaString containing the message of an object 
+ * was not supplied.
  */
 public class LuaError extends RuntimeException {
 	private static final long serialVersionUID = 1L;
@@ -45,6 +49,11 @@ public class LuaError extends RuntimeException {
 	
 	protected Throwable cause;
 
+	private LuaValue object;
+	
+	/** Get the string message if it was supplied, or a string 
+	 * representation of the message object if that was supplied.
+	 */
 	public String getMessage() {
 		if (traceback != null)
 			return traceback;
@@ -56,6 +65,17 @@ public class LuaError extends RuntimeException {
 		return m;
 	}
 
+	/** Get the LuaValue that was provided in the constructor, or 
+	 * a LuaString containing the message if it was a string error argument.
+	 * @return LuaValue which was used in the constructor, or a LuaString
+	 * containing the message.
+	 */
+	public LuaValue getMessageObject() {
+		if (object != null) return object;
+		String m = getMessage();
+		return m != null ? LuaValue.valueOf(m): null;
+	}
+	
 	/** Construct LuaError when a program exception occurs. 
 	 * <p> 
 	 * All errors generated from lua code should throw LuaError(String) instead.
@@ -87,6 +107,18 @@ public class LuaError extends RuntimeException {
 		this.level = level;
 	}	
 
+	/**
+	 * Construct a LuaError with a LuaValue as the message object,
+	 * and level to draw line number information from.
+	 * @param message message to supply
+	 * @param level where to supply line info from in call stack
+	 */
+	public LuaError(LuaValue message_object) {
+		super( message_object.tojstring() );
+		this.object = message_object;
+		this.level = 1;
+	}	
+
 
 	/** 
 	 * Get the cause, if any.

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

@@ -167,7 +167,9 @@ public class BaseLib extends TwoArgFunction implements ResourceFinder {
 	// "error", // ( message [,level] ) -> ERR
 	static final class error extends TwoArgFunction {
 		public LuaValue call(LuaValue arg1, LuaValue arg2) {
-			throw new LuaError( arg1.isnil()? null: arg1.tojstring(), arg2.optint(1) );
+			throw arg1.isnil()? new LuaError(null, arg2.optint(1)): 
+				arg1.isstring()? new LuaError(arg1.tojstring(), arg2.optint(1)): 
+					new LuaError(arg1);
 		}
 	}
 
@@ -216,8 +218,8 @@ public class BaseLib extends TwoArgFunction implements ResourceFinder {
 			try {
 				return varargsOf(TRUE, func.invoke(args.subargs(2)));
 			} catch ( LuaError le ) {
-				final String m = le.getMessage();
-				return varargsOf(FALSE, m!=null? valueOf(m): NIL);
+				final LuaValue m = le.getMessageObject();
+				return varargsOf(FALSE, m!=null? m: NIL);
 			} catch ( Exception e ) {
 				final String m = e.getMessage();
 				return varargsOf(FALSE, valueOf(m!=null? m: e.toString()));
@@ -369,8 +371,8 @@ public class BaseLib extends TwoArgFunction implements ResourceFinder {
 				try {
 					return varargsOf(TRUE, args.arg1().invoke(args.subargs(3)));
 				} catch ( LuaError le ) {
-					final String m = le.getMessage();
-					return varargsOf(FALSE, m!=null? valueOf(m): NIL);
+					final LuaValue m = le.getMessageObject();
+					return varargsOf(FALSE, m!=null? m: NIL);
 				} catch ( Exception e ) {
 					final String m = e.getMessage();
 					return varargsOf(FALSE, valueOf(m!=null? m: e.toString()));

test/junit/org/luaj/vm2/FragmentsTest.java

@@ -563,7 +563,6 @@ public class FragmentsTest extends TestSuite {
 					"return pcall(error)\n");
 		}
 
-		
 		public void testFindWithOffset() {
 			runFragment(LuaValue.varargsOf(LuaValue.valueOf(8), LuaValue.valueOf(5)),
 					"string = \"abcdef:ghi\"\n" +
@@ -571,5 +570,26 @@ public class FragmentsTest extends TestSuite {
 					"idx = substring:find(\":\")\n" +
 					"return #substring, idx\n");
 		}
+
+		public void testErrorArgIsString() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("string"), LuaValue.valueOf("c")),
+					"a,b = pcall(error, 'c'); return type(b), b\n");
+		}
+		public void testErrorArgIsNil() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("nil"), LuaValue.NIL),
+					"a,b = pcall(error); return type(b), b\n");
+		}
+		public void testErrorArgIsTable() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("table"), LuaValue.valueOf("d")),
+					"a,b = pcall(error, {c='d'}); return type(b), b.c\n");
+		}
+		public void testErrorArgIsNumber() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("string"), LuaValue.valueOf("1")),
+					"a,b = pcall(error, 1); return type(b), b\n");
+		}
+		public void testErrorArgIsBool() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("boolean"), LuaValue.TRUE),
+					"a,b = pcall(error, true); return type(b), b\n");
+		}
 	}
 }