How can I prevent a required custom field from accepting only spaces?

[Kmmaughs]

We have an issue where we need descriptions to be added to certain asks. Some of the engineers don't want to fill the data in and just type a space or a bunch of spaces in the required custom text field. How can I prevent this from being accepted?

I found this article: https://community.atlassian.com/t5/Jira-questions/Can-I-prevent-leading-and-trailing-whitespace-for-single-line/qaq-p/275894 which looks close to what I need, but I'm not sure how to write out the custom field name. 

This article was also close https://community.atlassian.com/t5/Jira-questions/Validator-to-restrict-spaces-on-custom-field-text/qaq-p/865782, but if they actually type in a description, then that's not quite what I'm looking for either. 

Any assistance with writing the groovy script (post function) that may be needed would be helpful.

[Mikael Sandberg]

I would put the check as a validation on the transition instead of a post function. Post functions will not prevent the user from just adding spaces to the description, if you do it as a validation the issue cannot move forward until the conditions are right.

But I would consider a different approach, because setting a validation only teaches the developers a different way of bypassing it. I would consider training them on how to write issues, and perhaps have a gate keeper (maybe their managers) that checks the issues to make sure the developers following the process. If the do not write a good description, push the issue back to them to correct it. A tool can do so much, but if a developer does not want to follow a process they will find a way around it. 

[Kmmaughs]

A validator makes sense. I definitely agree with training. The field is already a required field. Assuming I needed to so a Simple Scripted Validator, what would that look like? 

I was trying to see if something like

!cfValues["FIELD_NAME"]?.value.contains(" ") 

would work, but I don't want to prevent any/all spaces from being entered. Rather, I want to make sure the first character is not a space. 

[Mikael Sandberg]

Something like this should do it. This will remove any leading white spaces and compare it to the original description value.

String desc = issue.description
if (desc.trim() !== desc) {
    // error
}

But it will not prevent anyone from enter a dot or any other character that is not a space.

[Kmmaughs]

Thanks for sending this. I've been trying it out and getting a huge compilation error. Trying to resolve that. Until then, I'll let you know how it goes.