KBEC-00490 - Textarea Parameter May Break Your Code

Problem

You have a procedure with a parameter of type "textarea". A step which uses the parameter sometimes fails with:

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
/tmp/ecmdrAgent/agent.C3WA7LDJE25AFCTA.run-0932b0fa-6264-11ea-b4d7-06d0621b793d-0945eaa6-6264-11ea-aa90-06d0621b793d.cmd: 1: expecting anything but ''\n''; got it anyway @ line 1, column 15.
println "line1
^

1 error

Solution

This error tells that there is an error in the groovy code in the step command. But this looks impossible as the step command contains only one line:

println "$[input-paramater]"

According to Using property values:

=== Using property values

A job step can access a property value by two methods. The first method is substitution, using the $[ ] notation. Suppose you enter the following text as a command for a step:
make PLATFORM=$[platform]
Before running the step, CloudBees CD/RO finds the property named platform and substitutes its value in the command string in place of $[platform]. For example, if the property contains the value windows, the actual command executed is:
make PLATFORM=windows
The substitution method can be used for a command in a step and for any step fields, such as the resource or working directory. This method allows you to compute configuration information in an early step of a job, then use that configuration information to control later steps in the job.

So the above code only works when the value of "input-paramater" does NOT contain a carriage return. It fails with the error shown at the start of the article when the value of "input-paramater" includes multiple lines.

When using "textarea" parameter in groovy, Groovy Multiline String is helpful. The following code works fine:

def parameterSstring = '''
$[input-paramater]
'''
println parameterSstring