[Objective-C] [S1854] False Positive report of dead store inside GCD block

Clean Code Report False-positive / False-negative...
,
1

  • What language is this for?
    Objective-C

  • Which rule?
    S1854 - Unused assignments should be removed

  • Are you using
    SonarQube - I think it’s 8.x, trying to get precision on this from our devops.

  • How can we reproduce the problem? Give us a self-contained snippet of code (formatted text, no screenshots)

@property (nonatomic, strong) dispatch_queue_t syncQueue;
@property (nonatomic, strong) NSMutableDictionary<NSNumber *, NSNumber*> *threadSafeDict;

-(void)updateDictValue:(NSUInteger)value forKey:(NSUInteger *)key {
    dispatch_barrier_async(_syncQueue, ^{
        NSNumber *key = [NSNumber numberWithUnsignedInteger:key]; // (1)
        _threadSafeDict[key] = [NSNumber numberWithUnsignedInteger:value];
    });
}

(1) triggers Value stored to ‘key’ during its initialization is never read

  • Why do you believe it’s a false-positive/false-negative?
    key is used immediately in the next line.
2

Hey there.

Thanks for the report. We won’t be able to comment on it further until we know exactly what version of SonarQube is being used.

3

Sorry for the delay, I went OOO and got response just now.
We’re using 8.9.10 (build 61542)

4

Hey there.

Can you please upgrade to SonarQube v9.9 LTS and see if the false-positive persists? There have been efforts to suppress false-positives on this rule in the v9.x series.