Sonar detects bug but false positive

SonarCloud
1

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Hello,

    if (match && r.getCandidate().isPresent()) {

      // Durations are in nanoseconds, we don't need this kind of precision

      candidateTimer.record(r.getCandidate().get().getDuration(), TimeUnit.NANOSECONDS);

This is a transcript of the code.
Sonar asks me to call isPresent(), which is called one line before.

2

There is no “guarantee” that getCandidate() always returns the same object. You should store it in a local variable:

if (match) {
    Optional<SomeTypeWhichHasDurationField> candidate = r.getCandidate();
    if (candidate.isPresent()) {
       candidateTimer.record(candidate.get().getDuration(), TimeUnit.NANOSECONDS);
    }
}

Of course in your case it could be guaranteed, but SonarScanner doesn’t know enough context to accept it is as a valid code :wink:

1 Like
3

Alternatively:

if (match) {
    r.getCandidate()
        .map(SomeTypeWhichHasDurationField::getDuration)
        .ifPresent(duration -> candidateTimer.record(duration, TimeUnit.NANOSECONDS));
}
1 Like