This enhancement adds a conditional statement to the subtask creation post-function. Additional parameters have been added to the create/edit screen to configure the condition. Custom fields are enumerated and a select input is used to select the custom field to use as the condition. A text input is used to set the value that makes the condition true. Said custom field must be on the transition view screen and be set to the true condition during the transition (capture the rising edge from No to Yes, not just cf=Yes).
Due to how JIRA passes information around the location of the post-function in relation to the other post-functions matters. To mitigate this the enhancement compares a MutableIssue to the CustomField value AND inspects the transientVariables. This allows the post-function to be anywhere in the set of post-functions and still be accurate.
Not included but a useful addition would be a parameter to select "Edge Trigger" or "Field=Value" so the condition type is more flexible.
Conditional control has been added, however, the user interface and implementation is considerably different than indicated in the description. See [How to condition the creation of issues]