RViz may crash when TF's childFrameId is " "

[qinshichao]

When the childframeid of TF is ' ' and subscribed, RViz will crash.

When the childframeid of TF is '\a' or '\e' or other strings starting with' \ ',Abnormal display of RViz.

Your environment

• OS Version: e.g. Ubuntu 18.04
• ROS Distro: [Melodic]
• RViz, Qt, OGRE, OpenGl version as printed by rviz:

[rhaschke]

I cannot confirm these issues:
TF already rejects/ignores an empty child transform with the following error message on console:
[ERROR] ros.rosconsole_bridge.TF_NO_CHILD_FRAME_ID: Ignoring transform from authority "unknown_publisher" because child_frame_id not set

When sending a child frame with a non-printable control character in its name (e.g. \a), what exactly do you expect to happen?

[qinshichao]

I cannot confirm these issues: TF already rejects/ignores an empty child transform with the following error message on console: [ERROR] ros.rosconsole_bridge.TF_NO_CHILD_FRAME_ID: Ignoring transform from authority "unknown_publisher" because child_frame_id not set

When sending a child frame with a non-printable control character in its name (e.g. \a), what exactly do you expect to happen?

It's not empty, it's a space.
When sending a child frame with a non-printable control character in its name (e.g. \a), I expect it to remain '\ a' without escape.

[rhaschke]

It's not empty, it's a space.

Thanks for clarification. Now, I was able to reproduce the issue and the fix was trivial: #1700
To have a frame name like \a you obviously need to escape the backslash like so: "\\a"

[qinshichao]

To have a frame name like \a you obviously need to escape the backslash like so: `"\a"
Can string escape be prevented in code?

[rhaschke]

To have a frame name like \a you obviously need to escape the backslash like so: `"\a"

Can string escape be prevented in code?

No. That's about interpretation of chars in your programming language:

• \a is interpreted as a control character
• \\a is interpreted as backslash + letter a

[rhaschke]

crash fixed via #1700.