Currently, the Rebuilder plugin provides free text entry fields for choice parameters. An invalid entry will cause an IllegalArgumentException, so it would probably be best if the rebuilder could use the same choice options from the project being rebuilt for a drop-down or autocomplete field.
With an incorrect entry, the end user will see a 404-Page, and get something like the following entry in the log:
Mar 14, 2014 10:00:15 AM org.eclipse.jetty.util.log.JavaUtilLog warn
WARNING: /view/Main/job/ProjectX/185/rebuild/configSubmit
java.lang.IllegalArgumentException: Illegal choice: DecisionOnly
at hudson.model.ChoiceParameterDefinition.checkValue(ChoiceParameterDefinition.java:75)
at hudson.model.ChoiceParameterDefinition.createValue(ChoiceParameterDefinition.java:83)
at com.sonyericsson.rebuild.RebuildAction.getParameterValue(RebuildAction.java:387)
at com.sonyericsson.rebuild.RebuildAction.doConfigSubmit(RebuildAction.java:288)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)