NullPointerException in TextBlockGoogleStyleFormatting with text blocks in annotations

[eorloff]

I have read check documentation: https://checkstyle.org/checks/coding/textblockgooglestyleformatting.html
I have downloaded the latest checkstyle from: https://checkstyle.org/cmdline.html#Download_and_Run
I have executed the cli and showed it below, as cli describes the problem better than 1,000 words

$ javac Example.java

$ cat config.xml
<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
  "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
  "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
  <module name="TreeWalker">
    <module name="TextBlockGoogleStyleFormatting"/>
  </module>
</module>
$ cat Example.java
@SuppressWarnings(
  """
  Text block in annotation.
  """)
public class Example {
}
$ RUN_LOCALE="-Duser.language=en -Duser.country=US"

$ java $RUN_LOCALE -jar checkstyle-12.3.0-all.jar -c config.xml Example.java
Starting audit...
com.puppycrawl.tools.checkstyle.api.CheckstyleException: Exception was thrown while processing Example.java
        at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:313)
        at com.puppycrawl.tools.checkstyle.Checker.process(Checker.java:227)
        at com.puppycrawl.tools.checkstyle.Main.runCheckstyle(Main.java:429)
        at com.puppycrawl.tools.checkstyle.Main.runCli(Main.java:347)
        at com.puppycrawl.tools.checkstyle.Main.execute(Main.java:206)
        at com.puppycrawl.tools.checkstyle.Main.main(Main.java:130)
Caused by: java.lang.NullPointerException: Cannot invoke "com.puppycrawl.tools.checkstyle.api.DetailAST.getType()" because "parent" is null
        at com.puppycrawl.tools.checkstyle.checks.coding.TextBlockGoogleStyleFormattingCheck.openingQuotesAreAloneOnTheLine(TextBlockGoogleStyleFormattingCheck.java:136)
        at com.puppycrawl.tools.checkstyle.checks.coding.TextBlockGoogleStyleFormattingCheck.visitToken(TextBlockGoogleStyleFormattingCheck.java:87)
        at com.puppycrawl.tools.checkstyle.TreeWalker.notifyVisit(TreeWalker.java:390)
        at com.puppycrawl.tools.checkstyle.TreeWalker.processIter(TreeWalker.java:463)
        at com.puppycrawl.tools.checkstyle.TreeWalker.walk(TreeWalker.java:328)
        at com.puppycrawl.tools.checkstyle.TreeWalker.processFiltered(TreeWalker.java:208)
        at com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck.process(AbstractFileSetCheck.java:101)
        at com.puppycrawl.tools.checkstyle.Checker.processFile(Checker.java:341)
        at com.puppycrawl.tools.checkstyle.Checker.processFiles(Checker.java:300)
        ... 5 more
Checkstyle ends with 1 errors.

---

I expect checkstyle to not throw report any issues in the code and not fail with a NullPointerException.

The above example is a minimal example using @SuppressWarnings since that is an annotation that is available without libraries. The problem was encountered using another annotation where using a text block was more meaningful.

---

[romani]

@mohitsatr , we need hot fix.

@eorloff , do you have any opensource project that uses """ in such or more advanced way ? to let run validiton on it to make sure there is no other interesting cases of """ usage.

[eorloff]

@romani Unfortunately I do not have any opensource project where it is used. I encountered the problem when using jakarta.persistence.NamedNativeQuery and wanting to specify the query using a text block.

Searching Github I found this example that does something similar:
https://github.com/RedHatInsights/rhsm-subscriptions/blob/03fdeb5f7e60ec31217572e702207cd9712c5a59/src/main/java/org/candlepin/subscriptions/inventory/db/model/InventoryHost.java#L96

[romani]

thanks a lot
they actually use some fork of google style https://github.com/RedHatInsights/rhsm-subscriptions/blob/03fdeb5f7e60ec31217572e702207cd9712c5a59/config/checkstyle/checkstyle.xml ,so it good testing project.

[eorloff]

@romani I have just encountered the issue in another context that is available as opensource. Here the problem is encountered when configured picocli: https://gitlab.com/partisiablockchain/language/partisia-cli/-/blob/main/src/main/java/com/partisiablockchain/language/partisiacli/account/create/Create.java#L39

I hope that can help iron out the problem.

[DakshRJain737]

@romani came across the same problem while solving Issue: #18309 under the PR: #18309

[Praveen7294]

do you have any opensource project that uses """ in such or more advanced way ? to let run validiton on it to make sure there is no other interesting cases of """ usage.

@romani Please use Apache Pulsar, as it has multiple usages of Java text blocks.

some of them are:

https://github.com/apache/pulsar/blob/621b41f506764bc9573d2b2496620612cfb1ae36/pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImplTest.java#L1943

https://github.com/apache/pulsar/blob/621b41f506764bc9573d2b2496620612cfb1ae36/pulsar-broker-auth-oidc/src/test/java/org/apache/pulsar/broker/authentication/oidc/AuthenticationProviderOpenIDIntegrationTest.java#L112

https://github.com/apache/pulsar/blob/621b41f506764bc9573d2b2496620612cfb1ae36/pulsar-broker/src/test/java/org/apache/pulsar/schema/compatibility/SchemaCompatibilityCheckTest.java#L546

[romani]

fix is merged.

@eorloff , I hope this exception is not blocking you, and I can release it on last weekend of month, Dec 31. But I can do it quicker if you need.