[VELOCITY-872] Parse error from arithmetic expression as an argument to a method

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0
• Environment: VTL in user macro in Atlassian Confluence 5.9.4
• Assignee: Unassigned
• Reporter: Alexander Rosenberg
• Created: 09/May/16 03:03
• Updated: 07/Jan/18 15:46
• Resolved: 09/May/16 08:01

Description

The following results in a ParserErrorException:

## @noparams

#set ($list = ["a", "b", "c"])
#set ($last = $list.get($list.size() - 1))
<p>$last</p>

The message that appears in atlassian-confluence.log:

org.apache.velocity.exception.ParseErrorException: Encountered "-" at getRenderedContent[line 4, column 38]
Was expecting one of:
    "," ...
    ")" ...

        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1202)
        at org.apache.velocity.runtime.RuntimeInstance.evaluate(RuntimeInstance.java:1164)
        at org.apache.velocity.app.VelocityEngine.evaluate(VelocityEngine.java:219)
        at com.atlassian.confluence.util.velocity.VelocityUtils.writeRenderedContent(VelocityUtils.java:148)
        at com.atlassian.confluence.util.velocity.VelocityUtils.getRenderedContent(VelocityUtils.java:130)
        at com.atlassian.confluence.util.velocity.VelocityUtils.getRenderedContent(VelocityUtils.java:117)
        at com.atlassian.confluence.util.velocity.VelocityUtils.getRenderedContent(VelocityUtils.java:113)
        at com.atlassian.confluence.macro.GenericVelocityMacro.execute(GenericVelocityMacro.java:101)
        at com.atlassian.confluence.content.render.xhtml.view.macro.ViewMacroMarshaller.executeMacro(ViewMacroMarshaller.java:229)
        at com.atlassian.confluence.content.render.xhtml.view.macro.ViewMacroMarshaller.marshalInternal(ViewMacroMarshaller.java:156)
        at com.atlassian.confluence.content.render.xhtml.view.macro.ViewMacroMarshaller.lambda$marshal$445(ViewMacroMarshaller.java:113)
        at com.atlassian.confluence.impl.content.render.xhtml.analytics.MetricsCollectingMarshaller.marshal(MetricsCollectingMarshaller.java:49)
~~~snipped~~~

The Velocity parser does not appear to support arithmetic expressions as arguments in method calls. I find this extremely surprising, given the ubiquity of this basic syntax among languages. I hope that this is just a result of Confluence using an older version of Velocity. Regardless, it's annoying that absolutely nowhere in the documentation does it mention anything concerning this limitation.

This is a workaround:

## This works as expected:
#set ($lastIndex = $list.size() - 1)
#set ($last = $list.get($lastIndex))
<p>$last</p>