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https://issues.apache.org/jira/browse/JEXL-324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17025023#comment-17025023
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Henri Biestro commented on JEXL-324:
------------------------------------
Changeset: 1a304ae037c278ce2204989ecfdddf9ac449638c
Author: henrib <hen...@apache.org>
Date: 2020-01-28 11:26
Message: JEXL-324: refining parsing error reporting
> 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: 10m
> 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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