Jobs: OPTIONAL file input results in error

[scblack321]

From Sal:
I have a question r.e. fileInputs. If I want to present an OPTIONAL field, and leave the field blank in the app definition, either by setting "sourceUrl": null, or leaving it out entirely, I get this error if I do not specify that input in the job submission:

tapipy.errors.InternalServerError: message: Cannot invoke "String.startsWith(String)" because the return value of "edu.utexas.tacc.tapis.jobs.model.submit.JobFileInput.getSourceUrl()" is null

App hello-world in tenant portals. From app definition:

"fileInputs": [
{
"name": "File to modify",
"description": "The full greeting will be appended to the target .txt file",
"inputMode": "OPTIONAL",
"autoMountLocal": true,
"sourceUrl": null,
"targetPath": "in.txt"
}
],