[IGN-5933] A Derived tag's self-reference breaks when the tag name is changed

Ignition
1

When I use a self-reference ({this}) in the Read Expression of a Derived tag, the reference breaks when I change the name of the tag. I would expect the self-reference to not be dependent on the name.

Last Published Value: [null, Bad_NotFound("Path '[Testing]my_tag.tooltip' not found."), Thu Apr 21 10:31:14 MDT 2022 (1650558674394)]
Quality Diagnostics: Path '[Testing]my_tag.tooltip' not found.

Steps to reproduce:

  1. Create a derived tag
  2. Set source tag path to any other tag
  3. Set Read Expression to {this.tooltip} or any other property
  4. Click Apply
  5. Change the name of the tag

Expression tags don’t have this bug, only Derived tags.

Ignition version 8.1.14

2

Huh, good catch. If you restart the tag, the reference is fixed, at least.

3

You’re right. I didn’t realize you could restart a tag.