Formatting error when printing badly formatted messages

[DarrenBookless]

Description
I'm trying to debug some code which (on my end) is currently sending a badly formatted JSON message to the ROSBridge server. Naturally, the rosbridge server prints an error in response to this:

[rosbridge_websocket]: [Client 3f20257e-00de-480c-8438-ed6579be69ad] Received a message without an op. All messages require 'op' field with value one of: ['advertise', 'unadvertise', 'publish', 'subscribe', 'unsubscribe', 'fragment', 'advertise_service', 'call_service', 'service_response', 'unadvertise_service', 'advertise_action', 'action_feedback', 'action_result', 'send_action_goal', 'cancel_action_goal', 'unadvertise_action']. Original message was: {message_string}

Two problems with this:

• This isn't an accurate description of my problem - my message is actually just missing its back half and so doesn't close all of its "{"/"}" pairs
• As you can see, rather than printing the malformed message, it just says "Original message was: {message_string}"

From local testing, the problem is just a missing "f" from what should be an f-string here:

rosbridge_suite/rosbridge_library/src/rosbridge_library/protocol.py

Line 223 in 949d7c3

"Original message was: {message_string}",

• Library Version: (unsure how to check this, but current at the time of writing!)
• ROS Version: Humble
• Platform / OS: Ubuntu 24.04

Steps To Reproduce
Send a malformed json message to the rosbridge server.

Expected Behavior
Error message identifies cause of error and prints the malformed message.

Actual Behavior
Prints the literal text "{message_string}" without variable substitution.