Recipe NoValueOfOnStringType incorrectly removes String.valueOf on null-initialized constants, introducing runtime NPE

[jbessels]

What version of OpenRewrite are you using?

rewrite-recipe-bom 3.37.0
rrewrite-maven-plugin v6.46.1

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

 private static final String INCIDENT_OPEN_TASK = null;

 private String replaceIncidentGenericDummyValuesWithRealValues(String templateBody) {
        return templateBody
                .replace("$INCIDENT_OPEN_TASK", String.valueOf(INCIDENT_OPEN_TASK))
                // changes above code into the following
                // .replace("$INCIDENT_OPEN_TASK", INCIDENT_OPEN_TASK)
             
    }

Its part of our e2e/integration test repo and setting INCIDENT_OPEN_TASK to null is part of the test. The recipe does not check if the constant is null. If so do not remove the String.valueOf(). IntelliJ also gives a warning on the changed code: Passing 'null' argument to parameter annotated as non-null.

Boils down to

• INCIDENT_OPEN_TASK: Throws NullPointerException if null.
• String.valueOf(INCIDENT_OPEN_TASK): Converts null to the literal string "null", replacing the placeholder without crashing.

Test code generated by Ai and not tested.

  package org.openrewrite.staticanalysis;

 import org.junit.jupiter.api.Test;
 import org.openrewrite.test.RecipeSpec;
 import org.openrewrite.test.RewriteTest;

 import static org.openrewrite.java.Assertions.java;

 class SimplifyStringValueOfTest implements RewriteTest {

     @Override
     public void defaults(final RecipeSpec spec) {
         // Enforce the recipe under test
         spec.recipe(new SimplifyStringValueOf());
     }

     @Test
     void simplifyStringValueOf_whenConstantIsNull_doesNotChange() {
         rewriteRun(
             java(
                 """
                 class Test {
                     private static final String INCIDENT_OPEN_TASK = null;

                     private String replaceIncidentGenericDummyValuesWithRealValues(final String templateBody) {
                         return templateBody
                             .replace("$INCIDENT_OPEN_TASK", String.valueOf(INCIDENT_OPEN_TASK));
                     }
                 }
                 """
             )
         );
     }
 }