[Bug] Conditionally executed blocks should be reachable

[johannes...@gmail.com]

Hello! I am using SonarQube 6.5.0.27846 with SonarJava 4.15.0.12310.

I have the following method:

private static double selectPivot(double[][] matrix) {
        double maxLineQuotient = 0.0;
        int size = matrix.length;
        swapIndex = 0;
       
        for (int i = 0; i < size; i++) {
            // calculate row sum
            double lineQuotient = 0.0;
            for (int j = 0; j < size; j++) {
                lineQuotient += Math.abs(matrix[i][j]);
            }
           
            // skip row if sum is zero
            if (lineQuotient == 0.0) {
                continue;
            }
           
            // calculate the line quotient a[i][0]/sum
            lineQuotient = Math.abs(matrix[i][0]) / lineQuotient;
           
            // search the greatest line quotient
            if (lineQuotient > maxLineQuotient) {
                maxLineQuotient = lineQuotient;
                swapIndex = i;
            }
        }
       
        if (swapIndex > 0) {
            // swap line 0 with pivot line
            swapLines(matrix, 0, swapIndex);
        }
       
        // return pivot element
        return matrix[0][0];
    }

Now SonarQube reports a bug regarding the line if (swapIndex > 0) "Change this condition so that it does not always evaluate to "false""

I think this a bug in the scanner. i is changed in the for loop. So I think my code is correct. After the for loop variable swapIndex can be =0 or >0.

I updated SonarJava today. The bug did not exist in the version I had before.

[Nicolas Peru]

Hey, 

Sorry for the delay answering you : your case is a bit tricky but it is a variation of this problem of nested loops limit : https://jira.sonarsource.com/browse/SONARJAVA-1940 

No plan on our side in the shorterm to announce you but this issue should be fix someday. In the meantime you can mark the issue as falsepositive and follow this ticket.

Cheers, 

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Nicolas Peru | SonarSource

Senior Developer

https://twitter.com/benzonico

https://sonarsource.com