[GROOVY-7234] NullPointer Exception introduced in 2.3.1 and greater with JsonSlurper

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.3.9, 2.4.0-rc-1
• Component/s: JSON
• Environment: OS: Ubuntu 14.04 LTS; Java: JDK 1.7.0_65, vendor: Oracle Corporation 24.65-b04; Gradle 2.2.1; ; OS: Ubuntu 12.04 LTS; Java version: JDK 1.7.0_72, vendor: Oracle Corporation; Gradle 2.2.1
• Assignee: Unassigned
• Reporter: Sam Gleske
• Created: 01/Jan/15 14:18
• Updated: 22/Dec/23 11:38
• Resolved: 04/Sep/23 13:31

Description

When traversing a HashMap that was created from a parsed JSON file my unit tests start failing on Groovy versions 2.3.1 and later. There seems to be some sort of regression introduced.

To explore and debug this problem you may view my travis builds testing the latest versions of Groovy from 1.8.9 through 2.3.9.

https://travis-ci.org/samrocketman/jervis/builds/45526838

If you would like to check out and debug the problem yourself you can do the following:

git clone https://github.com/samrocketman/jervis.git
cd jervis
git checkout 2590bf2be5f8f2aaa1a25bcd63912506059da8c7
#passing build
GROOVY_VERSION="2.3.0" ./gradlew check
#first failing build
GROOVY_VERSION="2.3.1" ./gradlew check

gradlew check will automatically download Gradle 2.2.1, download the version of Groovy requested, assemble dependencies, compile, and execute unit tests.

[EDIT by blackdrag]
the issue can be reduced to this test

import groovy.json.JsonSlurper
def jsonSlurper = new JsonSlurper() 
def object = jsonSlurper.parseText('{ "o": {"name":"John Doe" }}')
assert object instanceof Map
assert object.o instanceof Map
assert object.o.name == "John Doe"
assert object.o[null] == null

the code is confirmed to work on 1.8.9 and in several versions of 2.0, 2.1 and 2.2. It seems to start failing in 2.3 (first tested version was 2.3.1)