Receiving rosout messages from rosbag2_recorder when running rosbag2_player

[scn-nmsc]

Description

ros2 bag play /testbag results in "rosbag2_recorder" actively publishing discovery log messages.

Expected Behavior

When starting rosbag2_player then "rosbag2_recorder" should not appear to be subscribing to messages according to /rosout topic.

Actual Behavior

When starting rosbag2_player (ros2 bag play /testbag) then "rosbag2_recorder" appears in the /rosout to be subscribing to topics (e.g. rosbag2_recorder: All requested topics are subscribed. Stopping discovery...)

To Reproduce

** Steps to reproduce the behavior, e.g.

1. run "ros2 bag play /testbag"
2. and subscribe to /rosout topic

System (please complete the following information)

• OS: Ubuntu 24.04
• ROS 2 Distro: Jazzy
• Install Method: APT
• Version: 0.26.4

[MichaelOrlov]

@scn-nmsc The Expected behaviour is unclear

When starting rosbag2_player then "rosbag2_recorder" should not appear to be subscribing to messages according to /rosout topic.

In the form how it is written is impossible to implement in the current design because rosbag2_recorder can't know that messages on the /rosout topic coming from the rosbag2_player

[fujitatomoya]

I am not sure what the problem is with this issue report... can you rephrase the issue header?

Are you saying that ros2 bag play /testbag should not play rosout topic according to the To Reproduce section in the issue header? if that is so, why do you not specify or exclude the topic to play? the same can be don on ros2 bag record as well, so user can have the full control what needs to be recorded and played?