Bug: NPE thrown when visitArrowFunction encounters empty body

[DovOps]

What version of OpenRewrite are you using?

This issue is occuring on the app.moderne.io tenant, when running on the FINOS organization. Several of the repos, when running 'Migrate to Spring Boot 3.3' recipe are erroring due to a JavaScriptVisitor with the same error

org.openrewrite.internal.RecipeRunException: java.lang.NullPointerException
  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:290)
  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
  org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
  org.openrewrite.java.JavaVisitor.lambda$visitContainer$35(JavaVisitor.java:1417)
  org.openrewrite.internal.ListUtils.map(ListUtils.java:243)
  org.openrewrite.internal.ListUtils.map(ListUtils.java:265)
  org.openrewrite.java.JavaVisitor.visitContainer(JavaVisitor.java:1417)
  org.openrewrite.java.JavaVisitor.visitMethodInvocation(JavaVisitor.java:914)
  ...
Caused by java.lang.NullPointerException: null
  java.base/java.util.Objects.requireNonNull(Objects.java:209)
  org.openrewrite.javascript.JavaScriptVisitor.visitArrowFunction(JavaScriptVisitor.java:105)
  org.openrewrite.javascript.tree.JS$ArrowFunction.acceptJavaScript(JS.java:440)
  org.openrewrite.javascript.tree.JS.accept(JS.java:52)
  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:250)
  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
  org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
  org.openrewrite.java.JavaVisitor.lambda$visitContainer$35(JavaVisitor.java:1417)
  ...

Results : https://app.moderne.io/results/DFdjDhiAr

How are you running OpenRewrite?

This is a simple recipe execution of the rewrite-spring org.openrewrite.java.spring.boot3.UpgradeSpringBoot_3_3 recipe on the app tenant.

What is the smallest, simplest way to reproduce the problem?

Will be looking to reproduce this locally so that the JavaScript file inputs of some of these projects, which look pretty harmless

What did you expect to see?

Expect to see the recipe execute, and worst case ignore some javascript files it finds.

What did you see instead?

What is the full stack trace of any errors you encountered?

org.openrewrite.internal.RecipeRunException: java.lang.NullPointerException
  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:290)
  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
  org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
  org.openrewrite.java.JavaVisitor.lambda$visitContainer$35(JavaVisitor.java:1417)
  org.openrewrite.internal.ListUtils.map(ListUtils.java:243)
  org.openrewrite.internal.ListUtils.map(ListUtils.java:265)
  org.openrewrite.java.JavaVisitor.visitContainer(JavaVisitor.java:1417)
  org.openrewrite.java.JavaVisitor.visitMethodInvocation(JavaVisitor.java:914)
  ...
Caused by java.lang.NullPointerException: null
  java.base/java.util.Objects.requireNonNull(Objects.java:209)
  org.openrewrite.javascript.JavaScriptVisitor.visitArrowFunction(JavaScriptVisitor.java:105)
  org.openrewrite.javascript.tree.JS$ArrowFunction.acceptJavaScript(JS.java:440)
  org.openrewrite.javascript.tree.JS.accept(JS.java:52)
  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:250)
  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)
  org.openrewrite.java.JavaVisitor.visitRightPadded(JavaVisitor.java:1367)
  org.openrewrite.java.JavaVisitor.lambda$visitContainer$35(JavaVisitor.java:1417)
  ...

Are you interested in contributing a fix to OpenRewrite?

I hope to look at how this might be fixed.

[DovOps]

This affects multiple recipe runs - OWASP Top 10, Java Security Best Practices, and Common Static Analysis, for example.

[OlegDokuka]

Hi, @DovOps!

Thank you for reporting this!
What you have observed is partially expected due to the rapid development of this language integration. We highly appreciate your patience!

We have released a new version OR-JS and CLI that depends on this. The new release has a couple of adjustments. Please re-ingest your projects to ensure you have the JS LSTs built with the most recent version of the js parser.

Let me know if this issue reappears.

Best,
Oleh

[DovOps]

Thanks @OlegDokuka - I actually pulled down rewrite-javascript and was looking to recreate this issue with some tests, but could not reproduce it. (Seems that some unit tests have migrated from Java over to native JS based on the gradle configs I was peeking at).

I re-ran things on the app tenant, which errored out with a slightly different NPE around visitFunctionType (instead of arrow function): Looks like this is running rewrite-spring 5.26.0 - and the LST was built with 3.27.8 within the last day.

org.openrewrite.internal.RecipeRunException: java.lang.NullPointerException

  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:290)

  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)

  org.openrewrite.javascript.JavaScriptVisitor.visitTypeInfo(JavaScriptVisitor.java:885)

  org.openrewrite.javascript.tree.JS$TypeInfo.acceptJavaScript(JS.java:3366)

  org.openrewrite.javascript.tree.JS.accept(JS.java:52)

  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:250)

  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)

  org.openrewrite.java.JavaVisitor.visitVariableDeclarations(JavaVisitor.java:948)

  ...

Caused by java.lang.NullPointerException: null

  java.base/java.util.Objects.requireNonNull(Objects.java:209)

  org.openrewrite.javascript.JavaScriptVisitor.visitFunctionType(JavaScriptVisitor.java:253)

  org.openrewrite.javascript.tree.JS$FunctionType.acceptJavaScript(JS.java:960)

  org.openrewrite.javascript.tree.JS.accept(JS.java:52)

  org.openrewrite.TreeVisitor.visit(TreeVisitor.java:250)

  org.openrewrite.TreeVisitor.visitAndCast(TreeVisitor.java:320)

  org.openrewrite.javascript.JavaScriptVisitor.visitTypeInfo(JavaScriptVisitor.java:885)

  org.openrewrite.javascript.tree.JS$TypeInfo.acceptJavaScript(JS.java:3366)

  ...

[OlegDokuka]

Hi, @DovOps!

Also, see that. Trying to reproduce them locally as well. Will keep you updated

thanks,
Oleh

[OlegDokuka]

Hi, @DovOps!

I appreciate your patience!
We redeployed our app tenant, so now it uses the rewrite-javascript, which includes the required fixes to run recipes normally. After that, I saw that only four repos out of 29 of the FINOS organizations failed with errors. After analysis, it seems that those errors are unrelated to what you initially observed.

Please check it from your side as well, and let me know if you encounter anything related to the original problem.

Thanks,
Oleh