[MATH-1149] unsafe initialization in DummyStepInterpolator

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3
• Fix Version/s: 3.4
• Assignee: Unassigned
• Reporter: M Kim
• Created: 22/Aug/14 11:35
• Updated: 26/Dec/14 19:50
• Resolved: 13/Sep/14 15:37

Description

DummyStepInterpolator.java

  public DummyStepInterpolator(final DummyStepInterpolator interpolator) {
    super(interpolator);
    currentDerivative = interpolator.currentDerivative.clone();
  }
   @Override
  protected StepInterpolator doCopy() {
    return new DummyStepInterpolator(this);
  }

A constructor in DummyStepInterpolator dereferences a field of the parameter, but a NullPointerException can occur during a call to doCopy().

Test.java

public void test1() throws Throwable {
  DummyStepInterpolator var0 = new DummyStepInterpolator();
  var0.copy();
}

Here in Test.java, a NPE occurs because copy() calls doCopy() which calls DummyStepInterpolator(final DummyStepInterpolator) that passes var0 as an argument.

I think this constructor should have a null check for interpolator.currentDerivative like NordsieckStepInterpolator does.

NordsieckStepInterpolator.java

    public NordsieckStepInterpolator(final NordsieckStepInterpolator interpolator) {
        super(interpolator);
        scalingH      = interpolator.scalingH;
        referenceTime = interpolator.referenceTime;
        if (interpolator.scaled != null) {
            scaled = interpolator.scaled.clone();
        }
        if (interpolator.nordsieck != null) {
            nordsieck = new Array2DRowRealMatrix(interpolator.nordsieck.getDataRef(), true);
        }
        if (interpolator.stateVariation != null) {
            stateVariation = interpolator.stateVariation.clone();
        }
    }

    @Override
    protected StepInterpolator doCopy() {
        return new NordsieckStepInterpolator(this);
    }