From 4f3cd304a1bc61cfa4d363a36009f8170ee4b8d0 Mon Sep 17 00:00:00 2001
From: James Roseborough <james.roseborough@luaj.org>
Date: Mon, 19 Apr 2010 16:11:55 +0000
Subject: [PATCH] Improve error handling in coroutines.

---
 src/core/org/luaj/vm2/LuaThread.java | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/core/org/luaj/vm2/LuaThread.java b/src/core/org/luaj/vm2/LuaThread.java
index dbcf67bc..1d75b2ac 100644
--- a/src/core/org/luaj/vm2/LuaThread.java
+++ b/src/core/org/luaj/vm2/LuaThread.java
@@ -36,6 +36,7 @@ public class LuaThread extends LuaValue implements Runnable {
 	private static final int STATUS_RUNNING       = 1;
 	private static final int STATUS_NORMAL        = 2;
 	private static final int STATUS_DEAD          = 3;
+	private static final int STATUS_ERROR         = 4;
 	private static final String[] STATUS_NAMES = { 
 		"suspended", 
 		"running", 
@@ -158,8 +159,12 @@ public class LuaThread extends LuaValue implements Runnable {
 		synchronized ( this ) {
 			try {
 				this.args = func.invoke(this.args);
-			} finally {
 				status = STATUS_DEAD;
+			} catch ( Throwable t ) {
+				String msg = t.getMessage();
+				this.args = valueOf(msg!=null? msg: t.toString());
+				status = STATUS_ERROR;
+			} finally {
 				this.notify();
 			}
 		}
@@ -214,7 +219,12 @@ public class LuaThread extends LuaValue implements Runnable {
 				this.wait();
 				
 				// copy return values from yielding stack state
-				return varargsOf(LuaValue.TRUE, this.args);
+				if ( status == STATUS_ERROR ) {
+					status = STATUS_DEAD;
+					return varargsOf(FALSE, this.args);
+				} else {
+					return varargsOf(TRUE, this.args);
+				}
 	
 			} catch ( Throwable t ) {
 				status = STATUS_DEAD;