Jenkins has a plugin "Active Choices Parameter" that allows you to create dynamic and interactive parameters for your Jenkins jobs. These parameters can change based on user input or other factors, providing a more customized and user-friendly experience when triggering a job.

For instance, one can have a dropdown list of options where the available choices depend on certain conditions or data sources. This can help users make informed selections when running jobs.

Here's a simplified example using the Active Choices Parameter plugin in a Jenkins job:

if (state == "California") {
  return ["Los Angeles", "San Francisco", "San Diego"];
} else if (state == "New York") {
  return ["New York City", "Buffalo", "Albany"];
} else if (state == "Texas") {
  return ["Houston", "Dallas", "Austin"];
} 

In this example, the options array dynamically generates the choices for the parameter based on a specific logic.

Currently, Bitbucket Cloud only supports fixed, allowlisted variable values. It's not possible to generate variable values dynamically. The sole method to achieve this currently is through pipeline step command automation.

Also, it will be beneficial if the allowed values are populated based on the input from a file at run time.