NoWhitespaceAfterCheck for some array initialization crashes Checkstyle

[denizarsan]

$ javac C.java

$ cat C.java

class C {
    int i = new int[]{1}[0];
}

$ cat config.xml

<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.3//EN" "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<module name="Checker">
  <module name="TreeWalker">
    <module name="NoWhitespaceAfter"/>
  </module>
</module>

$ java -jar checkstyle-7.8.2-all.jar -c config.xml C.java

Starting audit...
com.puppycrawl.tools.checkstyle.api.CheckstyleException: Exception was thrown while processing C.java
        at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:295)
        at com.puppycrawl.tools.checkstyle.Checker.process(Checker.java:213)
        at com.puppycrawl.tools.checkstyle.Main.runCheckstyle(Main.java:425)
        at com.puppycrawl.tools.checkstyle.Main.runCli(Main.java:359)
        at com.puppycrawl.tools.checkstyle.Main.main(Main.java:174)
Caused by: java.lang.NullPointerException
        at com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck.getPositionAfter(NoWhitespaceAfterCheck.java:175)
        at com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck.visitToken(NoWhitespaceAfterCheck.java:133)
        at com.puppycrawl.tools.checkstyle.TreeWalker.notifyVisit(TreeWalker.java:370)
        at com.puppycrawl.tools.checkstyle.TreeWalker.processIter(TreeWalker.java:507)
        at com.puppycrawl.tools.checkstyle.TreeWalker.walk(TreeWalker.java:312)
        at com.puppycrawl.tools.checkstyle.TreeWalker.processFiltered(TreeWalker.java:184)
        at com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck.process(AbstractFileSetCheck.java:78)
        at com.puppycrawl.tools.checkstyle.Checker.processFile(Checker.java:316)
        at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:286)
        ... 4 more
Checkstyle ends with 1 errors.

---

The tool crashes with a NPE for the given config and class. The problem is the array-initialization expression that creates an array with concrete values (in this case "1") and then indexes into it.

Please let me know if you want me to help with fixing this.

Attention: suppressed at circleci by - checkstyle/contribution@284acd3

[rnveach]

@denizarsan Please don't report issues using snapshot version. It is unclear what commit you used or if you added any of your own custom code on top of it. Please use release versions and update your first post.

Feel free to provide us with a fix. I don't know how easy/hard this will be.

[denizarsan]

@rnveach I have updated my post. I'm using the latest release (7.8.2) from https://sourceforge.net/projects/checkstyle/files/checkstyle/

[sergileon]

I am on it

[Vladlis]

checkstyle/contribution@284acd3 is still to be reverted

[romani]

commit is reverted in contribution

[romani]

I think this issue is fixed.

[Vladlis]

Caused by: com.puppycrawl.tools.checkstyle.api.CheckstyleException: Exception was thrown while processing /pipeline/source/contribution/checkstyle-tester/src/main/java/checkstyle/src/test/resources/com/puppycrawl/tools/checkstyle/checks/whitespace/nowhitespaceafter/InputNoWhitespaceAfterArrayDeclarations.java
 at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:295)
 at com.puppycrawl.tools.checkstyle.Checker.process(Checker.java:213)
 at org.apache.maven.plugin.checkstyle.exec.DefaultCheckstyleExecutor.executeCheckstyle(DefaultCheckstyleExecutor.java:252)
 at org.apache.maven.plugin.checkstyle.AbstractCheckstyleReport.executeReport(AbstractCheckstyleReport.java:473)
 ... 29 more
Caused by: java.lang.NullPointerException
 at com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck.getPositionAfter(NoWhitespaceAfterCheck.java:181)
 at com.puppycrawl.tools.checkstyle.checks.whitespace.NoWhitespaceAfterCheck.visitToken(NoWhitespaceAfterCheck.java:139)

is caught by Wercker on checkstyle/sevntu-checkstyle job after uncommenting checkstyle/contribution@284acd3, @sergileon please investigate and fix
This might be another issue

[sergileon]

i run job on the master and not see exception

[romani]

@Vladlis , I do not see problem on master wercker, please share link

[romani]

I am closing issue, till smb show we exact and reproducible case

[msimko81]

Hi, I have the same problem as described in the original bug request.

If I use the following initialization block, the checkstyle plugin fails with NPE:

int group = new int[] { 1, 2, 3, 4, 9 }[RandomUtils.nextInt(0, 4)];

Splitting the code to two lines is the workaround, checkstyle is happy with this:

int[] availableGroups = new int[] { 1, 2, 3, 4, 9 };
int group = availableGroups[RandomUtils.nextInt(0, 4)];

[romani]

please make sure you use checkstyle version 8.3 and above to run without exception.

[msimko81]

Thanks. I have used the default plugin referenced from gradle 4.6
By specifying the checkstyle tool version 8.10, everything works now.