LuaItemStack: Fix and document behavior of set_name, set_count, set_wear, set_metadata

doc/lua_api.txt

@@ -2152,13 +2152,16 @@ ItemStack: A stack of items.
 methods:
 - is_empty(): return true if stack is empty
 - get_name(): returns item name (e.g. "default:stone")
-- set_name(itemname)
+- set_name(itemname): returns true/false (success)
+  ^ clears item on failure
 - get_count(): returns number of items on the stack
-- set_count(count)
+- set_count(count): returns true/false (success)
+  ^ clears item on failure
 - get_wear(): returns tool wear (0-65535), 0 for non-tools
-- set_wear(wear)
+- set_wear(wear): returns true/false (success)
+  ^ clears item on failure
 - get_metadata(): returns metadata (a string attached to an item stack)
-- set_metadata(metadata)
+- set_metadata(metadata): returns true
 - clear(): removes all items from the stack, making it empty
 - replace(item): replace the contents of this stack (item can also
     be an itemstring or table)

src/script/lua_api/l_item.cpp

@@ -63,11 +63,15 @@ int LuaItemStack::l_set_name(lua_State *L)
 	NO_MAP_LOCK_REQUIRED;
 	LuaItemStack *o = checkobject(L, 1);
 	ItemStack &item = o->m_stack;
+
+	bool status = true;
 	item.name = luaL_checkstring(L, 2);
-
-	if (item.name == "" || item.empty())
+	if (item.name == "" || item.empty()) {
 		item.clear();
+		status = false;
+	}
 
+	lua_pushboolean(L, status);
 	return 1;
 }
 
@@ -87,11 +91,18 @@ int LuaItemStack::l_set_count(lua_State *L)
 	NO_MAP_LOCK_REQUIRED;
 	LuaItemStack *o = checkobject(L, 1);
 	ItemStack &item = o->m_stack;
-	item.count = luaL_checkinteger(L, 2);
 
-	if (item.name == "" || item.empty())
+	bool status;
+	lua_Integer count = luaL_checkinteger(L, 2);
+	if (count <= 65535) {
+		item.count = count;
+		status = true;
+	} else {
 		item.clear();
+		status = false;
+	}
 
+	lua_pushboolean(L, status);
 	return 1;
 }
 
@@ -111,11 +122,18 @@ int LuaItemStack::l_set_wear(lua_State *L)
 	NO_MAP_LOCK_REQUIRED;
 	LuaItemStack *o = checkobject(L, 1);
 	ItemStack &item = o->m_stack;
-	item.wear = luaL_checkinteger(L, 2);
 
-	if (item.wear > 65535)
+	bool status;
+	lua_Integer wear = luaL_checkinteger(L, 2);
+	if (wear <= 65535) {
+		item.wear = wear;
+		status = true;
+	} else {
 		item.clear();
+		status = false;
+	}
 
+	lua_pushboolean(L, status);
 	return 1;
 }
 
@@ -138,11 +156,9 @@ int LuaItemStack::l_set_metadata(lua_State *L)
 
 	size_t len = 0;
 	const char *ptr = luaL_checklstring(L, 2, &len);
-	if (ptr)
 	item.metadata.assign(ptr, len);
-	else
-		item.metadata = "";
 
+	lua_pushboolean(L, true);
 	return 1;
 }