parser_pyx: build value maps for requied messages (#939)

can/parser_pyx.pyx

@@ -46,13 +46,6 @@ cdef class CANParser:
       msg_name_to_address[name] = msg.address
       address_to_msg_name[msg.address] = name
 
-      self.vl[msg.address] = {}
-      self.vl[name] = self.vl[msg.address]
-      self.vl_all[msg.address] = {}
-      self.vl_all[name] = self.vl_all[msg.address]
-      self.ts_nanos[msg.address] = {}
-      self.ts_nanos[name] = self.ts_nanos[msg.address]
-
     # Convert message names into addresses and check existence in DBC
     cdef vector[pair[uint32_t, int]] message_v
     for i in range(len(messages)):
@@ -62,6 +55,14 @@ cdef class CANParser:
         raise RuntimeError(f"could not find message {repr(c[0])} in DBC {self.dbc_name}")
       message_v.push_back((address, c[1]))
 
+      name = address_to_msg_name[address]
+      self.vl[address] = {}
+      self.vl[name] = self.vl[address]
+      self.vl_all[address] = {}
+      self.vl_all[name] = self.vl_all[address]
+      self.ts_nanos[address] = {}
+      self.ts_nanos[name] = self.ts_nanos[address]
+
     self.can = new cpp_CANParser(bus, dbc_name, message_v)
     self.update_strings([])