KB-1150 "The rule contains an expression that cannot be tested" error thrown when using xpathsnippet() function

Nick Vigilante — Tue, 28 Feb 2017 17:14:27 GMT

Current Revision posted to Appian Knowledge Base by Nick Vigilante on 2/28/2017 5:14:27 PM

Symptoms

An xpathsnippet() expression with valid inputs fails to save or execute with the following error on the interface:

The rule contains an expression that cannot be tested

The corresponding error in the application-server log is as follows:

INFO  [stdout] (ajp-/0.0.0.0:8009-4) com.appiancorp.process.expression.ExpressionRuntimeException$AppianExceptionProvider: Expression evaluation error at function 'xpathsnippet': Error evaluating function 'xpathsnippet' : An error occurred while trying to parse the XML stream. (APNX-1-4198-000)
...
Caused by: org.apache.xerces.impl.io.MalformedByteSequenceException: Invalid byte 1 of 1-byte UTF-8 sequence.
...

Cause

The application server’s –Dfile.encoding property is not set to UTF-8 and is therefore unable to parse the XML input correctly.

Action

To resolve this issue, set the value of –Dfile.encoding to UTF-8 in standalone.custom.(bat|sh) and restart JBoss.

Affected Versions

This article applies to all versions of Appian using JBoss EAP as an application server.

Last Reviewed: February 2017

Tags: expression rules, interfaces, SAIL, application server, application design, jboss