Improve error reporting.

src/test/java/org/luaj/vm/LuaJTest.java

@@ -70,6 +70,10 @@ public class LuaJTest extends TestCase {
 		runTest( "compare" );
 	}
 
+	public void testErrors() throws IOException, InterruptedException {
+		runTest( "errors" );
+	}
+
 	public void testMathLib() throws IOException, InterruptedException {
 		runTest( "mathlib" );
 	}
@@ -129,7 +133,7 @@ public class LuaJTest extends TestCase {
 	public void testUpvalues2() throws IOException, InterruptedException {
 		runTest( "upvalues2" );
 	}
-
+//*/
 	private void runTest( String testName ) throws IOException, InterruptedException {
 
 		// new lua state 

src/test/res/errors.lua

@@ -0,0 +1,88 @@
+-- object ids
+require 'ids'
+ids = {}
+
+-- test of common types of errors
+local function c(f,...) return f(...) end
+local function b(...) return c(...) end
+local function a(...) return pcall(b,...) end
+s = 'some string'
+local t = {}
+
+-- error message tests
+print( 'a(error)', a(error) )
+print( 'a(error,"msg")', a(error,"msg") )
+print( 'a(error,"msg",0)', a(error,"msg",0) )
+print( 'a(error,"msg",1)', a(error,"msg",1) )
+print( 'a(error,"msg",2)', a(error,"msg",2) )
+print( 'a(error,"msg",3)', a(error,"msg",3) )
+print( 'a(error,"msg",4)', a(error,"msg",4) )
+print( 'a(error,"msg",5)', a(error,"msg",5) )
+print( 'a(error,"msg",6)', a(error,"msg",6) )
+
+-- call errors
+print( 'a(nil())', a(function() return n() end) )
+print( 'a(t())  ', a(function() return t() end) )
+print( 'a(s())  ', a(function() return s() end) )
+print( 'a(true())', a(function() local b = true; return b() end) )
+
+-- arithmetic errors
+print( 'a(nil+1)', a(function() return nil+1 end) )
+print( 'a(a+1)  ', a(function() return a+1 end) )
+print( 'a(s+1)  ', a(function() return s+1 end) )
+print( 'a(true+1)', a(function() local b = true; return b+1 end) )
+
+-- table errors
+print( 'a(nil.x)', a(function() return n.x end) )
+print( 'a(a.x)  ', a(function() return a.x end) )
+print( 'a(s.x)  ', a(function() return s.x end) )
+print( 'a(true.x)', a(function() local b = true; return b.x end) )
+print( 'a(nil.x=5)', a(function() n.x=5 end) )
+print( 'a(a.x=5)  ', a(function() a.x=5 end) )
+print( 'a(s.x=5)  ', a(function() s.x=5 end) )
+print( 'a(true.x=5)', a(function() local b = true; b.x=5 end) )
+
+-- len operator 
+print( 'a(#nil) ', a(function() return #n end) )
+print( 'a(#t)   ', a(function() return #t end) )
+print( 'a(#s)   ', a(function() return #s end) )
+print( 'a(#a)   ', a(function() return #a end) )
+print( 'a(#true)', a(function() local b = true; return #b end) )
+
+-- comparison errors
+print( 'a(nil>1)', a(function() return nil>1 end) )
+print( 'a(a>1)  ', a(function() return a>1 end) )
+print( 'a(s>1)  ', a(function() return s>1 end) )
+print( 'a(true>1)', a(function() local b = true; return b>1 end) )
+
+-- unary minus errors
+print( 'a(-nil)', a(function() return -n end) )
+print( 'a(-a)  ', a(function() return -a end) )
+print( 'a(-s)  ', a(function() return -s end) )
+print( 'a(-true)', a(function() local b = true; return -b end) )
+
+-- pairs
+print( 'a(pairs(nil))', a(function() return id(pairs(nil,{})) end) )
+print( 'a(pairs(a))  ', a(function() return id(pairs(a,{})) end) )
+print( 'a(pairs(s))  ', a(function() return id(pairs(s,{})) end) )
+print( 'a(pairs(t))  ', a(function() return id(pairs(t,{})) end) )
+print( 'a(pairs(true))', a(function() local b = true; return id(pairs(b,{})) end) )
+
+-- setmetatable
+function sm(...)
+	return id(setmetatable(...))
+end
+print( 'a(setmetatable(nil))', a(function() return sm(nil,{}) end) )
+print( 'a(setmetatable(a))  ', a(function() return sm(a,{}) end) )
+print( 'a(setmetatable(s))  ', a(function() return sm(s,{}) end) )
+print( 'a(setmetatable(true))', a(function() local b = true; return sm(b,{}) end) )
+print( 'a(setmetatable(t))  ', a(function() return sm(t,{}) end) )
+print( 'a(setmetatable(t*))  ', a(function() return sm(t,{__metatable={}}) end) )
+print( 'a(setmetatable(t))  ', a(function() return sm(t,{}) end) )
+t = {}
+print( 'a(setmetatable(t))  ', a(function() return sm(t,{}) end) )
+print( 'a(setmetatable(t*))  ', a(function() return sm(t,{__metatable='some string'}) end) )
+print( 'a(setmetatable(t))  ', a(function() return sm(t,{}) end) )
+
+-- bad args to error!
+print( 'error("msg","arg")', a(function() error('some message', 'some bad arg') end) )

src/test/res/ids.lua

@@ -0,0 +1,14 @@
+-- utility to give tables and functions uniform ids for testing
+ids = {}
+function id(obj)
+	if not obj or type(obj) == 'number' or type(obj) == 'string' or type(obj) == 'boolean' then
+		return obj
+	end
+	local v = ids[obj]
+	if v then
+		return v
+	end
+	table.insert(ids,obj)
+	ids[obj] = type(obj)..'.'..tostring(#ids)
+	return ids[obj]
+end