Player attrs: permits to remove an attribute by setting value to nil (#5716)

* Player attrs: permits to remove an attribute by setting value to nil

When doing player:set_attribute("attr", nil) remove attribute

Also remove a useless check on C++ API part (already done by checkplayer)

Fix #5709

2 files changed, 14 insertions, 3 deletions

diff --git a/src/content_sao.h b/src/content_sao.h
index e08795579..0dad54805 100644
--- a/src/content_sao.h
+++ b/src/content_sao.h
@@ -277,6 +277,16 @@ public:
 		return true;
 	}
 
+	inline void removeExtendedAttribute(const std::string &attr)
+	{
+		PlayerAttributes::iterator it = m_extra_attributes.find(attr);
+		if (it == m_extra_attributes.end())
+			return;
+
+		m_extra_attributes.erase(it);
+		m_extended_attributes_modified = true;
+	}
+
 	inline const PlayerAttributes &getExtendedAttributes()
 	{
 		return m_extra_attributes;
diff --git a/src/script/lua_api/l_object.cpp b/src/script/lua_api/l_object.cpp
index 6f61ab55c..c7a31d048 100644
--- a/src/script/lua_api/l_object.cpp
+++ b/src/script/lua_api/l_object.cpp
@@ -1202,9 +1202,10 @@ int ObjectRef::l_set_attribute(lua_State *L)
 	}
 
 	std::string attr = luaL_checkstring(L, 2);
-	std::string value = luaL_checkstring(L, 3);
-
-	if (co->getType() == ACTIVEOBJECT_TYPE_PLAYER) {
+	if (lua_isnil(L, 3)) {
+		co->removeExtendedAttribute(attr);
+	} else {
+		std::string value = luaL_checkstring(L, 3);
 		co->setExtendedAttribute(attr, value);
 	}
 	return 1;