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Recipe UseMapOf generates Map.of() with nullable values or duplicate keys, causing runtime NullPointerException

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#1,307 0 comentarios 0 reacciones 0 asignados Ver en GitHub

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Evaluación

Dificultad
4/5
Tiempo estimado
3-5 días
Aptitud para principiantes
55/100
Tipo de issue
Error
Claridad
Bien especificado
Estado de actividad
Activo
Stack tecnológico
java
Área
backend

Línea de trabajo

Start with the UseMapOf recipe and UseMapOfTest.java, which the issue names, and trace how put arguments are checked before conversion to Map.of. Review the existing null check and add coverage for nullable values and duplicate keys; the issue includes a parameter example and expected behavior. Done means unsafe maps are left unchanged while safe maps still rewrite, with the regression tests passing.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

bug

I checked out all relevant OpenRewrite repo's, fed the AI with existing recipe name and a very careful description. Antigravity with Vertex / Gemini was then tasked to check and test. .Also to create a ticket for it, using your default template. The result is shown beneath.

What version of OpenRewrite are you using?

  • rewrite-core: 8.93.0
  • rewrite-maven-plugin: 6.50.0

How are you running OpenRewrite?

Maven plugin with recipe org.openrewrite.java.migrate.util.UseMapOf.

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

UseMapOf currently only checks !J.Literal.isLiteralValue(arg, null). When parameters, method calls, or duplicate keys are passed to .put(k, v), it rewrites to Map.of(...), which strictly rejects nulls (NPE per JEP 269) and duplicate keys (IllegalArgumentException):

import java.util.HashMap;
import java.util.Map;

class Test {
    Map<String, Object> create(String dataOwner) {
        Map<String, Object> map = new HashMap<>();
        map.put("owner", dataOwner); // nullable parameter
        map.put("id", "123");
        return map;
    }
}

What did you expect to see?

Do not rewrite into Map.of(...) unless keys and values are statically guaranteed non-null, and keys are distinct.

What did you see instead?

Rewritten to new HashMap<>(Map.of("owner", dataOwner, "id", "123")), throwing NullPointerException at runtime when dataOwner is null:

java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "val" is null
    at java.base/java.util.KeyValueHolder.<init>(KeyValueHolder.java:54)
    at java.base/java.util.Map.of(Map.java:1320)
Solution in UseMapOf.java

Abort rewrite unless both key and value satisfy isKnownNonNull(Expression) and keys are unique:

if (!isKnownNonNull(key) || !isKnownNonNull(value)) {
    hasUnsafePut = true;
    break;
}

isKnownNonNull returns true only for:

  • Non-null J.Literal, primitives, J.NewClass, J.NewArray, String concatenation (+)
  • Class literals (X.class), Enums, and non-null static final constants
Regression Test in UseMapOfTest.java
@Test
void parameterInPutNotRewritten() {
    rewriteRun(
      java(
        """
          import java.util.HashMap;
          import java.util.Map;

          class Test {
              void m(String dataOwner) {
                  Map<String, Object> map = new HashMap<>();
                  map.put("dataOwner", dataOwner);
                  map.put("id", "6");
              }
          }
          """
      )
    );
}
Lenguaje dominante
Java
Estrellas
160
Forks
133
Merge medio
7 h 49 min
PR fusionados (30 d)
60

Preparar el entorno

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

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