Rails crashed with a slim markup that had duplicate data- item

[salex]

Don't know is it is Rails or Slim, but I made a mistake in changing an element in a slim template.

The element was:

    progress.w3-white[value="0" max="30" id="progressBar" style="width:100%"
      data-target="pickTicket.progressBar" 
      data-action="load->pickTicket#startTimer"]

This is using Stimulus.js and had a problem using getElementById and changed it to a data-target, bat forgot I already had it in the element.

    progress.w3-white[value="0" max="30" data-target="pickTicket.progressBar" style="width:100%"
      data-target="pickTicket.progressBar" 
      data-action="load->pickTicket#startTimer"]

So I had two data-target="pickTicket.progressBar"

Rails balked, not just with an error, but a public 500.error page in development.

Took a little while to find it in that the log did not give much help in finding the problem,

Removing the duplicate made things right. I know this was my mistake, but just thought I'd point it out.