I am using an Active Choices Reactive Reference Parameter to render HTML inputs.

In the HTML, if I set the input type to text, the values are passed along to the pipeline correctly.

If I set the input type to checkbox, the values are not passed along, only true/false.

The desired behaviour does work as expected if I use a regular Active Choices Parameter with 'Choice Type' set to checkboxes, however this does not allow me to use custom HTML.

WORKS: Groovy script (Regular Active Choices Parameter):

return ['dog', 'cat', 'mouse']

NOT WORKING: Groovy script (Reactive Reference - Formatted HTML):

options = ['dog', 'cat', 'mouse']
output = ""
options.each { thing ->
    output += """<input type="checkbox" name="value" value="${thing}">${thing}<br/>"""
}
return output

Sample pipeline:

pipeline {
    agent any
    stages {
        stage('Test checkboxes') {
            steps {
                echo "ACTIVE: ${params.ACTIVE_CHECKBOXES}"
                echo "REACTIVE: ${params.REACTIVE_CHECKBOXES}"
            }
        }
    }
}

Run pipeline:

Output:

[Pipeline] stage
[Pipeline] { (Test checkboxes)
[Pipeline] echo
ACTIVE: cat,mouse
[Pipeline] echo
REACTIVE: true,true,false

More info:

If I change the input type to 'radio' or 'text', behaviour is again as expected.

[Pipeline] echo
REACTIVE: dog

[Pipeline] echo
REACTIVE: dog,cat,mouse