From 4c2add3832097ffee44e438c81200fb1c332985c Mon Sep 17 00:00:00 2001
From: UnlegitDqrk <finn.abadi@outlook.de>
Date: Sun, 1 Mar 2026 19:36:19 +0100
Subject: [PATCH] Fixed issue: #94

---
 .../src/main/java/org/luaj/vm2/LuaClosure.java | 18 ++++++++++--------
 core/src/main/java/org/luaj/vm2/LuaError.java  |  4 ++++
 .../test/java/org/luaj/vm2/FragmentsTest.java  | 11 +++++++++++
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/core/src/main/java/org/luaj/vm2/LuaClosure.java b/core/src/main/java/org/luaj/vm2/LuaClosure.java
index b9bb652e..d862a2b5 100644
--- a/core/src/main/java/org/luaj/vm2/LuaClosure.java
+++ b/core/src/main/java/org/luaj/vm2/LuaClosure.java
@@ -591,19 +591,19 @@ public class LuaClosure extends LuaFunction {
 	 *  Run the error hook if there is one
 	 *  @param msg the message to use in error hook processing.
 	 * */
-	String errorHook(String msg, int level) {
-		if (globals == null ) return msg;
+	LuaValue errorHook(LuaValue msgobj, String msg, int level) {
+		if (globals == null ) return LuaValue.valueOf(msg);
 		final LuaThread r = globals.running;
 		if (r.errorfunc == null)
-			return globals.debuglib != null?
+			return LuaValue.valueOf(globals.debuglib != null?
 					msg + "\n" + globals.debuglib.traceback(level):
-					msg;
+					msg);
 		final LuaValue e = r.errorfunc;
 		r.errorfunc = null;
 		try {
-			return e.call( LuaValue.valueOf(msg) ).tojstring();
+			return e.call(msgobj != null ? msgobj : LuaValue.NIL);
 		} catch ( Throwable t ) {
-			return "error in error handling";
+			return LuaValue.valueOf("error in error handling");
 		} finally {
 			r.errorfunc = e;
 		}
@@ -628,7 +628,9 @@ public class LuaClosure extends LuaFunction {
 			}
 		}
 		le.fileline = file + ":" + line;
-		le.traceback = errorHook(le.getMessage(), le.level);
+		LuaValue error = errorHook(le.getMessageObject(), le.getMessage(), le.level);
+		le.setMessageObject(error);
+		le.traceback = error != null ? error.tojstring() : null;
 	}
 
 	private UpValue findupval(LuaValue[] stack, short idx, UpValue[] openups) {
@@ -656,4 +658,4 @@ public class LuaClosure extends LuaFunction {
 	}
 
 
-}
\ No newline at end of file
+}
diff --git a/core/src/main/java/org/luaj/vm2/LuaError.java b/core/src/main/java/org/luaj/vm2/LuaError.java
index 37a8df8d..c6708017 100644
--- a/core/src/main/java/org/luaj/vm2/LuaError.java
+++ b/core/src/main/java/org/luaj/vm2/LuaError.java
@@ -75,6 +75,10 @@ public class LuaError extends RuntimeException {
 		String m = getMessage();
 		return m != null ? LuaValue.valueOf(m): null;
 	}
+
+	public void setMessageObject(LuaValue messageObject) {
+		this.object = messageObject;
+	}
 	
 	/** Construct LuaError when a program exception occurs. 
 	 * <p> 
diff --git a/jse/src/test/java/org/luaj/vm2/FragmentsTest.java b/jse/src/test/java/org/luaj/vm2/FragmentsTest.java
index 33846915..bf343ace 100644
--- a/jse/src/test/java/org/luaj/vm2/FragmentsTest.java
+++ b/jse/src/test/java/org/luaj/vm2/FragmentsTest.java
@@ -591,6 +591,17 @@ public class FragmentsTest extends TestSuite {
 			runFragment(LuaValue.varargsOf(LuaValue.valueOf("boolean"), LuaValue.TRUE),
 					"a,b = pcall(error, true); return type(b), b\n");
 		}
+		public void testXpcallHandlerResultReplacesStringError() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("table"), LuaValue.valueOf(1)),
+					"local ok, err = xpcall(function() error('oh no') end, function(e) return { marker = 1, original = e } end)\n" +
+					"return type(err), err.marker\n");
+		}
+		public void testXpcallHandlerGetsOriginalErrorObject() {
+			runFragment(LuaValue.varargsOf(LuaValue.valueOf("table"), LuaValue.valueOf(1)),
+					"local source = { marker = 1 }\n" +
+					"local ok, err = xpcall(function() error(source) end, function(e) return e end)\n" +
+					"return type(err), err.marker\n");
+		}
 		public void testBalancedMatchOnEmptyString() {
 			runFragment(LuaValue.NIL, "return (\"\"):match(\"%b''\")\n");
 		}