java:S6204 Collections.reverse(List) is not considered a modification

Clean Code Report False-positive / False-negative...
1
  • SonarLint for IntelliJ 8.2.0.68615
  • IntelliJ IDEA 2023.1.2 (Ultimate Edition), Build #IU-231.9011.34, built on May 16, 2023
  • OpenJDK 17.0.6+10

When collection a Stream with Collectors.toList(), SonarLint java:S6204 issue suggests to use the Stream.toList() instead when the collected list is not going to be modified. Collections.reverse(List) seems not to be detected as a function implying mutation, even if annotated with @Contract(mutates = "param1").

import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

class JavaS6204ListModification {
    
    void undetectedMutatedList() {
        List<Integer> toBeModifiedList = Stream.of(1, 2, 3)
                .collect(Collectors.toList());
        Collections.reverse(toBeModifiedList);
    }
}
4

Hi @Jueverhard,

Thank you for reporting.
Here is the ticket to track fixing the issue.

All the best,

Irina

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