[JEXL-416] Null-valued pragma throws NPE in 3.3

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3
• Fix Version/s: 3.4.0

Environment

JEXL 3.3
Java 21 (21+35) Red Hat, Inc.
Linux 5.15.133.1-microsoft-standard-WSL2 (amd64)

• Assignee: Henri Biestro
• Reporter: William Price
• Created: 22/Nov/23 21:39
• Updated: 23/Nov/23 16:06
• Resolved: 23/Nov/23 16:06

Description

Version 3.2.1 seemed to allow null as a value for pragmas, but version 3.3 throws NPE.  I'm not necessarily advocating for null pragma values, but it's a behavior regression due to the use of TreeMap::merge. Even if disallowing nulls was desired, it should be a JexlException not NPE.

Passes on 3.2.1:

var script = engine.createScript("#pragma myNull null\n");
var pragmas = script.getPragmas();
assertTrue(pragmas.containsKey("myNull"), "pragma key present?");
assertNull(pragmas.get("myNull"), "expected null value"); 

Behavior on 3.3:

assertThrows(
    NullPointerException.class,
    () -> engine.createScript("#pragma myNull null\n"));

java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:233)
	at java.base/java.util.TreeMap.merge(TreeMap.java:743)
	at org.apache.commons.jexl3.parser.JexlParser.declarePragma(JexlParser.java:557)
	at org.apache.commons.jexl3.parser.Parser.Pragma(Parser.java:1246)
	at org.apache.commons.jexl3.parser.Parser.JexlScript(Parser.java:63)
	at org.apache.commons.jexl3.parser.Parser.parse(Parser.java:25)
	at org.apache.commons.jexl3.internal.Engine.parse(Engine.java:1009)
	at org.apache.commons.jexl3.internal.Engine.createScript(Engine.java:617)
	at org.apache.commons.jexl3.internal.Engine.createScript(Engine.java:69)
	at org.apache.commons.jexl3.JexlEngine.createScript(JexlEngine.java:375)