Examples of errors detected by the V6021 diagnostic

V6021. The value is assigned to the 'x' variable but is not used.

SpotBugs

V6021 [CWE-563] The value is assigned to the 'old' variable but is not used. MergeSummarizeAndView.java 279

private void load() {
  ....
  long old = System.currentTimeMillis() - options.maxAge * (24 * 3600 * 1000L);
  if (options.baselineDate != null) {
    long old2 = options.baselineDate.getTime();
    if (old2 > old) {
      old = old2;
    }
  }
  .... // The 'old' variable is not used.
}

SpotBugs

V6021 [CWE-563] The value is assigned to the 'priority' variable but is not used. FindNonShortCircuit.java 197

private void reportBug() {
  int priority = LOW_PRIORITY;
  String pattern = "NS_NON_SHORT_CIRCUIT";

  if (sawDangerOld) {
    if (sawNullTestVeryOld) {
      priority = HIGH_PRIORITY;                                           // <=
    }
    if (sawMethodCallOld || sawNumericTestVeryOld && sawArrayDangerOld) {
      priority = HIGH_PRIORITY;                                           // <=
      pattern = "NS_DANGEROUS_NON_SHORT_CIRCUIT";
    } else {
      priority = NORMAL_PRIORITY;                                         // <=
    }
  }

  bugAccumulator.accumulateBug(
    new BugInstance(this, pattern, priority).addClassAndMethod(this), this);
}

CUBA Platform

V6021 Variable 'source' is not used. DefaultHorizontalLayoutDropHandler.java(177)

@Override
protected void handleHTML5Drop(DragAndDropEvent event) {
  LayoutBoundTransferable transferable = (LayoutBoundTransferable) event
          .getTransferable();
  HorizontalLayoutTargetDetails details = (HorizontalLayoutTargetDetails) event
          .getTargetDetails();
  AbstractOrderedLayout layout = (AbstractOrderedLayout) details
          .getTarget();
  Component source = event.getTransferable().getSourceComponent(); // <=
  int idx = (details).getOverIndex();

  HorizontalDropLocation loc = (details).getDropLocation();
  if (loc == HorizontalDropLocation.CENTER
          || loc == HorizontalDropLocation.RIGHT) {
      idx++;
  }
  Component comp = resolveComponentFromHTML5Drop(event);
  if (idx >= 0) {
    layout.addComponent(comp, idx);
  } else {
    layout.addComponent(comp);
  }
  if (dropAlignment != null) {
    layout.setComponentAlignment(comp, dropAlignment);
  }
}

Similar errors can be found in some other places:

• V6021 Variable 'source' is not used. DefaultHorizontalLayoutDropHandler.java(175)
• V6021 The value is assigned to the 'r' variable but is not used. ExcelExporter.java(262)
• V6021 Variable 'over' is not used. DefaultCssLayoutDropHandler.java(49)
• And 3 additional diagnostic messages.

Huawei Cloud

V6021 Variable 'url' is not used. TriggerV2Service.java(95)

public ActionResponse deleteAllTriggersForFunction(String functionUrn)
{
  checkArgument(!Strings.isNullOrEmpty(functionUrn), ....);
  String url = ClientConstants.FGS_TRIGGERS_V2 +
               ClientConstants.URI_SEP +
               functionUrn;
  return deleteWithResponse(uri(triggersUrlFmt, functionUrn)).execute();
}

Rhino

V6021 The value is assigned to the 'localMax' variable but is not used. NativeRegExp.java(568)

public class NativeRegExp extends IdScriptableObject {
  ....
  private static boolean calculateBitmapSize(....) {
    ....
    switch (src[index]) {
      case '\\':
        ....
        switch (c) {
          ....
          case 'c':
            if ((index < end) && isControlLetter(src[index]))
              localMax = (char) (src[index++] & 0x1F);         // <=
            else --index;
            localMax = '\\';
            break;
          ....
        }
      ....
    }
    // use localMax
    ....
  }
  ....
}

Rhino

V6021 The value is assigned to the 'nameString' variable but is not used. QName.java(293)

final class QName extends IdScriptableObject {
  ....
  QName constructQName(XMLLibImpl lib,
                       Context cx,
                       Object namespace,
                       Object name) {
    String nameString = null;
    if (name instanceof QName) {
      if (namespace == Undefined.instance) {
        return (QName) name;
      } else {
        nameString = ((QName) name).localName();          // <=
      }
    }
    if (name == Undefined.instance) {
      nameString = "";
    } else {
      nameString = ScriptRuntime.toString(name);
    }
    ....
    return newQName(lib, q_uri, q_localName, q_prefix);
  }
  ....
}