Tests and fixes for debug.setupvalue, getupvalue, setmetatable, and getmetatable

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

@@ -31,7 +31,7 @@ import org.luaj.vm.LPrototype;
 import org.luaj.vm.LString;
 import org.luaj.vm.LTable;
 import org.luaj.vm.LValue;
-import org.luaj.vm.LocVars;
+import org.luaj.vm.LuaErrorException;
 import org.luaj.vm.LuaState;
 
 public class DebugLib extends LFunction {
@@ -348,15 +348,27 @@ public class DebugLib extends LFunction {
 	private void getmetatable(LuaState vm) {
 		LValue object = vm.topointer(2);
 		vm.resettop();
-		vm.pushlvalue( object.luaGetMetatable() );
+		LValue mt = object.luaGetMetatable();
+		if ( mt != null )
+			vm.pushlvalue( object.luaGetMetatable() );
+		else
+			vm.pushnil();
 	}
 
 	private void setmetatable(LuaState vm) {
 		LValue object = vm.topointer(2);
-		LValue table  = vm.totable(3);
-		object.luaSetMetatable(table);
-		vm.resettop();
-		vm.pushlvalue( object );
+		try {
+			if ( ! vm.isnoneornil(3) )
+				object.luaSetMetatable(vm.checktable(3));
+			else
+				object.luaSetMetatable(null);
+			vm.resettop();
+			vm.pushboolean(true);
+		} catch ( LuaErrorException e ) {
+			vm.resettop();
+			vm.pushboolean(false);
+			vm.pushstring(e.toString());
+		}
 	}
 
 	private void getregistry(LuaState vm) {
@@ -364,14 +376,26 @@ public class DebugLib extends LFunction {
 		vm.pushlvalue( new LTable() );
 	}
 
+	private LString findupvalue(LClosure c, int up) {
+		if ( c.upVals != null && up > 0 && up <= c.upVals.length ) {
+			if ( c.p.upvalues != null && up <= c.p.upvalues.length )
+				return c.p.upvalues[up-1];
+			else
+				return new LString( "."+up+"" );
+		}
+		return null;
+	}
+
 	private void getupvalue(LuaState vm) {
 		LFunction func = vm.checkfunction(2);
 		int up = vm.checkint(3);
 		vm.resettop();
 		if ( func instanceof LClosure ) {
 			LClosure c = (LClosure) func;
-			if ( c.upVals != null && up > 0 && up < c.upVals.length ) {
-				vm.pushlvalue(c.upVals[up].getValue());
+			LString name = findupvalue(c, up);
+			if ( name != null ) {
+				vm.pushlstring(name);
+				vm.pushlvalue(c.upVals[up-1].getValue());
 				return;
 			}
 		}
@@ -385,12 +409,10 @@ public class DebugLib extends LFunction {
 		vm.resettop();
 		if ( func instanceof LClosure ) {
 			LClosure c = (LClosure) func;
-			if ( c.upVals != null && up > 0 && up < c.upVals.length ) {
-				c.upVals[up].setValue(value);
-				if ( c.p.upvalues != null && up < c.p.upvalues.length )
-					vm.pushlvalue( c.p.upvalues[up] );
-				else
-					vm.pushstring( "."+up+"" );
+			LString name = findupvalue(c, up);
+			if ( name != null ) {
+				c.upVals[up-1].setValue(value);
+				vm.pushlstring(name);
 				return;
 			}
 		}

src/core/org/luaj/vm/LValue.java

@@ -181,7 +181,7 @@ public class LValue {
 	 * @return this if unchanged, or new LTable if copied using weak table 
 	 */
 	public LTable luaSetMetatable(LValue metatable) {
-		throw new LuaErrorException( "cannot set metatable for "+metatable.luaGetTypeName());
+		throw new LuaErrorException( "cannot set metatable for "+this.luaGetTypeName());
 	}
 
 	/** Valid for all types: return the int value identifying the type of this value */

src/test/res/debuglib.lua

@@ -1,5 +1,5 @@
 
-local print,tostring,_G = print,tostring,_G
+local print,tostring,_G,pcall,ipairs,isnumber = print,tostring,_G,pcall,ipairs,isnumber
 local e,f,g,h,s
 print( 'has debug', debug~=nil )
 if not debug then error( 'no debug' ) end
@@ -49,6 +49,75 @@ do lvl=2,3
 	end
 end
 
+
+print( '----- debug.getupvalue, debug.setupvalue' )
+local m,n,o = 101,102,103
+f = function(p,q,r)
+	local p,q,r = 104,105,106
+	local g = function(s,t,u)
+		local v,w,x = 107,108,109
+		return function()
+			return m,n,o,p,q,r,v,w,x
+		end
+	end
+	return g
+end
+g = f()
+h = g()
+local callh = function()
+	local t = {}
+	for i,v in ipairs( { pcall(h) } ) do
+		t[i] = tostring(v)
+	end
+	return table.concat(t,',')
+end 
+print( 'h', h() )
+local funs = { f, g, h }
+local names = { 'f', 'g', 'h' }
+for i=1,3 do
+	local fun,name = funs[i],names[i]	
+	for index=0,10 do
+		local s1,x1,y1 = pcall( debug.getupvalue, fun, index )
+		local s2,x2,y2 = pcall( debug.setupvalue, fun, index, 666000+i*111000+index )
+		local s3,x3,y3 = pcall( debug.getupvalue, fun, index )
+		print( name..' -> '..i..'-'..index..' '.. 
+			'get='..tostring(s1)..','..tostring(x1)..','..tostring(y1)..' '.. 
+			'set='..tostring(s2)..','..tostring(x2)..','..tostring(y2)..' '.. 
+			'get='..tostring(s3)..','..tostring(x3)..','..tostring(y3)..' '..
+			'tbl='..callh() )
+	end
+end
+
+print( '----- debug.setmetatable, debug.getmetatable' )
+local a = {a='bbb'}
+local b = {}
+local mt = {__index={b='ccc'}}
+print( 'a.a='..tostring(a.a)..' a.b='..tostring(a.b)..' b.a='..tostring(b.a)..' b.b='..tostring(b.b)) 
+local s1,x1,y1 = pcall( debug.getmetatable, a )
+local s2,x2,y2 = pcall( debug.setmetatable, a, mt )
+print( 'a.a='..tostring(a.a)..' a.b='..tostring(a.b)..' b.a='..tostring(b.a)..' b.b='..tostring(b.b)) 
+local s3,x3,y3 = pcall( debug.getmetatable, a )
+local s4,x4,y4 = pcall( debug.getmetatable, b )
+local s5,x5,y5 = pcall( debug.setmetatable, a, nil )
+print( 'a.a='..tostring(a.a)..' a.b='..tostring(a.b)..' b.a='..tostring(b.a)..' b.b='..tostring(b.b)) 
+local s6,x6,y6 = pcall( debug.getmetatable, a )
+if not s1 then print( 's1 error', x1 ) end
+if not s2 then print( 's2 error', x2 ) end
+if not s3 then print( 's3 error', x3 ) end
+if not s4 then print( 's4 error', x4 ) end
+if not s5 then print( 's5 error', x5 ) end
+if not s6 then print( 's6 error', x6 ) end
+print( 'get='..tostring(s1)..','..tostring(x1==nil)..','..tostring(y1) )
+print( 'set='..tostring(s2)..','..tostring(x2==a)..','..tostring(y2) ) 
+print( 'get='..tostring(s3)..','..tostring(x3==mt)..','..tostring(y3) ) 
+print( 'get='..tostring(s4)..','..tostring(x4==nil)..','..tostring(y4) ) 
+print( 'set='..tostring(s5)..','..tostring(x5==a)..','..tostring(y5) ) 
+print( 'get='..tostring(s6)..','..tostring(x6==nil)..','..tostring(y6) ) 
+print( pcall( debug.getmetatable, 1 ) )
+-- print( pcall( debug.setmetatable, 1, {} ) )
+-- print( pcall( debug.setmetatable, 1, nil ) )
+
+
 --[[
 local f = function(a)
 	return 'f:'..tostring(a)..'|'..tostring(b)