Publishing a message of the wrong type can cause a hard error

[rotu]

Bug report

Required Info:

• Operating System:
  • Windows 10
• Installation type:
  • binaries
• Version or commit hash:
• DDS implementation:
• Client library (if applicable):
  • rclpy

Steps to reproduce issue

import rclpy
rclpy.init()
import std_msgs.msg

n = rclpy.create_node('mynode')
p = n.create_publisher(std_msgs.msg.UInt32,'mytopic')
p.publish(42)

Expected behavior

Either the value is converted silently to the compatible message type or a catchable error is thrown.

Actual behavior

The python interpreter crashes and the following is found in Event Viewer:

Faulting application name: python.exe, version: 3.7.3150.1013, time stamp: 0x5c9954fa
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0xc0000005
Fault offset: 0x0000000000000000
Faulting process id: 0x73b0
Faulting application start time: 0x01d4f4e426ff3935
Faulting application path: C:\Python37\python.exe
Faulting module path: unknown
Report Id: 682bc596-629a-4933-962f-ffe339ad65c1
Faulting package full name: 
Faulting package-relative application ID: 

Additional information

In the file publisher.py, there should probably be a check isinstance(msg, self.msg_type) or type(msg) is self.msg_type and a TypeError thrown.

[dirk-thomas]

Thanks for the report. PR #317 address this for publishing messages as well as various other API.

In the future when you have a specific proposal please consider to create a pull request for it.