[jira] [Closed] (JEXL-324) JexlEngine.createExpression("new()").getParsedText() throws NPE

["Henri Biestro (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/JEXL-324?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Henri Biestro closed JEXL-324.
------------------------------

> JexlEngine.createExpression("new()").getParsedText() throws NPE
> ---------------------------------------------------------------
>
>                 Key: JEXL-324
>                 URL: https://issues.apache.org/jira/browse/JEXL-324
>             Project: Commons JEXL
>          Issue Type: Bug
>    Affects Versions: 3.1
>            Reporter: David Costanzo
>            Assignee: Henri Biestro
>            Priority: Minor
>             Fix For: 3.2
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> JEXL is able to parse the expression "new()", but some parts of the system do not expect this.  Specifically, if you try to get the parsed text, JEXL throws a NullPointerException instead of returning "new()".
> I expect {{JexlExpression.getParsedText()}} to return a String  for any expression that was successfully parsed. So either {{createExpression()}} should throw an exception or {{getParsedText()}} should return "new()".  My preference is for {{createExpression()}} to fail and I'll try to submit a PR for this.
>  
> *Impact:*
> My program tries to fail fast with a clear error message when a user attempts to "register" a function using a reserved name (function registration happens outside of JEXL and is implemented by populating a JexlContext with a parsed expression). My program does this by probing for valid function names by parsing {{_FUNCTION_NAME_+"()"}} and checking for errors.  Since "new()" is a legal expression, my program has a special case to disallow "new".  If {{createExpression("new()")}} threw an exception, then I could remove the special case.
>  
> *Steps to Reproduce:*
>  
> {code:java}
>     @Test
>     public void testNew() throws IOException {
>         JexlEngine jexl = new JexlBuilder().create();
>         try {
>             JexlExpression expression = jexl.createExpression("new()");
>             Assert.assertEquals("new()", expression.getParsedText());
>         } catch (JexlException.Parsing exception) {
>         }
>     }
> {code}
>  
> *What Happens:*
> {{getParsedText()}} throws a {{NullPointerException}}.
> *Expected Result:*
> Either {{JexlEngine.createExpression()}} throws a {{JexlException.Parsing}} or {{expression.getParsedText()}} returns "new()".
> *Note:*
> This was found on JEXL 3.1, the latest official release. I reproduced it on a snapshot of JEXL 3.2 built from GitHub source.
>  



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