Fixed issue: #86

core/src/main/java/org/luaj/vm2/libs/DebugLib.java

@@ -173,10 +173,16 @@ public class DebugLib extends TwoArgFunction {
 			// find the stack info
 			DebugLib.CallFrame frame;
 			if ( func.isnumber() ) {
-				frame = callstack.getCallFrame(func.toint());
-				if (frame == null)
-					return NONE;
-				func = frame.f;
+				int level = func.toint();
+				if (level == 0) {
+					frame = null;
+					func = this;
+				} else {
+					frame = callstack.getCallFrame(level);
+					if (frame == null)
+						return NONE;
+					func = frame.f;
+				}
 			} else if ( func.isfunction() ) {
 				frame = callstack.findCallFrame(func);
 			} else {
@@ -453,12 +459,14 @@ public class DebugLib extends TwoArgFunction {
 		if (s.inhook || s.hookfunc == null) return;
 		s.inhook = true;
 		try {
+			callstack().onCall(s.hookfunc.checkfunction());
 			s.hookfunc.call(type, arg);
 		} catch (LuaError e) {
 			throw e;
 		} catch (RuntimeException e) {
 			throw new LuaError(e);
 		} finally {
+			callstack().onReturn();
 			s.inhook = false;
 		}
 	}

jse/src/test/java/org/luaj/vm2/FragmentsTest.java

@@ -140,6 +140,28 @@ public class FragmentsTest extends TestSuite {
 				"return sum\n");
 		}
 
+		public void testDebugGetInfoLevelZeroReturnsGetInfoFunction() {
+			runFragment(
+				LuaValue.TRUE,
+				"return debug.getinfo(0, 'f').func == debug.getinfo\n");
+		}
+
+		public void testDebugGetInfoInsideHookSeesHookFunction() {
+			runFragment(
+				LuaValue.TRUE,
+				"local ok = false\n" +
+				"local hook\n" +
+				"hook = function()\n" +
+				"  local info = debug.getinfo(1, 'f')\n" +
+				"  ok = info ~= nil and info.func == hook\n" +
+				"  debug.sethook()\n" +
+				"end\n" +
+				"debug.sethook(hook, 'c')\n" +
+				"local function foo() end\n" +
+				"foo()\n" +
+				"return ok\n");
+		}
+
 		public void testLongIntegerLiteralPrecision() {
 			runFragment(
 				LuaValue.varargsOf(new LuaValue[] {