Grails war error: codecOut.print(())

Just stumbled upon this after upgrading to Grails 1.3.7. One of our gsp pages had an empty code block in it "${}" which was causing this error when trying to build the war. Running the app locally had no problems and Grails 1.3.4 had no errors when building a war with this empty code block, but Grails 1.3.7 did. Since there's nothing on the Internet about this little annoyance I'm putting it here so someone else seeing that error in their console knows what to look for.

Just to put the information in one clean place:

When trying to build a war, I got an error pointing to "codecOut.print(())" as failing. The culprit was an empty code block in one of the gsp files. That is, in one of the gsp files this occured: "${}". Clearly, someone forgot to fill in a value. I filled in the correct value and the war built without issue.