Program: 192157
Project: 192157
Buggy source:
private boolean handleTouchEvent(MotionEvent ev){
  if (mSv.getTaskViews().size() == 0) {
    return false;
  }
  final TaskStackLayoutAlgorithm layoutAlgorithm=mSv.mLayoutAlgorithm;
  int action=ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
{
      mDownX=(int)ev.getX();
      mDownY=(int)ev.getY();
      mLastY=mDownY;
      mDownScrollP=mScroller.getStackScroll();
      mActivePointerId=ev.getPointerId(0);
      mActiveTaskView=findViewAtPoint(mDownX,mDownY);
      mScroller.stopScroller();
      mScroller.stopBoundScrollAnimation();
      Utilities.cancelAnimationWithoutCallbacks(mScrollFlingAnimator);
      mSv.cancelAllTaskViewAnimations();
      ArrayMap<View,Animator> existingAnimators=new ArrayMap<>(mSwipeHelperAnimations);
      for (int i=0; i < existingAnimators.size(); i++) {
        existingAnimators.get(existingAnimators.keyAt(i)).end();
      }
      mSwipeHelperAnimations.clear();
      initOrResetVelocityTracker();
      mVelocityTracker.addMovement(ev);
      break;
    }
case MotionEvent.ACTION_POINTER_DOWN:
{
    final int index=ev.getActionIndex();
    mActivePointerId=ev.getPointerId(index);
    mDownX=(int)ev.getX(index);
    mDownY=(int)ev.getY(index);
    mLastY=mDownY;
    mDownScrollP=mScroller.getStackScroll();
    mVelocityTracker.addMovement(ev);
    break;
  }
case MotionEvent.ACTION_MOVE:
{
  int activePointerIndex=ev.findPointerIndex(mActivePointerId);
  int y=(int)ev.getY(activePointerIndex);
  int x=(int)ev.getX(activePointerIndex);
  if (!mIsScrolling) {
    int yDiff=Math.abs(y - mDownY);
    int xDiff=Math.abs(x - mDownX);
    if (Math.abs(y - mDownY) > mScrollTouchSlop && yDiff > xDiff) {
      mIsScrolling=true;
      float stackScroll=mScroller.getStackScroll();
      List<TaskView> taskViews=mSv.getTaskViews();
      for (int i=taskViews.size() - 1; i >= 0; i--) {
        layoutAlgorithm.addUnfocusedTaskOverride(taskViews.get(i).getTask(),stackScroll);
      }
      layoutAlgorithm.setFocusState(TaskStackLayoutAlgorithm.STATE_UNFOCUSED);
      final ViewParent parent=mSv.getParent();
      if (parent != null) {
        parent.requestDisallowInterceptTouchEvent(true);
      }
      MetricsLogger.action(mSv.getContext(),MetricsEvent.OVERVIEW_SCROLL);
    }
  }
  if (mIsScrolling) {
    float deltaP=layoutAlgorithm.getDeltaPForY(mDownY,y);
    float curScrollP=mDownScrollP + deltaP;
    float minScrollP=layoutAlgorithm.mMinScrollP;
    float maxScrollP=layoutAlgorithm.mMaxScrollP;
    if (curScrollP < minScrollP || curScrollP > maxScrollP) {
      float clampedScrollP=Utilities.clamp(curScrollP,minScrollP,maxScrollP);
      float overscrollP=(curScrollP - clampedScrollP);
      float overscrollX=Math.abs(overscrollP) / MAX_OVERSCROLL;
      curScrollP=clampedScrollP + (Math.signum(overscrollP) * (OVERSCROLL_INTERP.getInterpolation(overscrollX) * MAX_OVERSCROLL));
    }
    mScroller.setStackScroll(curScrollP);
    mStackViewScrolledEvent.updateY(y - mLastY);
    EventBus.getDefault().send(mStackViewScrolledEvent);
  }
  mLastY=y;
  mVelocityTracker.addMovement(ev);
  break;
}
case MotionEvent.ACTION_POINTER_UP:
{
int pointerIndex=ev.getActionIndex();
int pointerId=ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
  final int newPointerIndex=(pointerIndex == 0) ? 1 : 0;
  mActivePointerId=ev.getPointerId(newPointerIndex);
  mDownX=(int)ev.getX(pointerIndex);
  mDownY=(int)ev.getY(pointerIndex);
  mLastY=mDownY;
  mDownScrollP=mScroller.getStackScroll();
}
mVelocityTracker.addMovement(ev);
break;
}
case MotionEvent.ACTION_UP:
{
mVelocityTracker.addMovement(ev);
mVelocityTracker.computeCurrentVelocity(1000,mMaximumVelocity);
int activePointerIndex=ev.findPointerIndex(mActivePointerId);
int y=(int)ev.getY(activePointerIndex);
int velocity=(int)mVelocityTracker.getYVelocity(mActivePointerId);
if (mIsScrolling) {
if (mScroller.isScrollOutOfBounds()) {
  mScroller.animateBoundScroll();
}
 else if (Math.abs(velocity) > mMinimumVelocity) {
  float minY=mDownY + layoutAlgorithm.getYForDeltaP(mDownScrollP,layoutAlgorithm.mMaxScrollP);
  float maxY=mDownY + layoutAlgorithm.getYForDeltaP(mDownScrollP,layoutAlgorithm.mMinScrollP);
  mScroller.fling(mDownScrollP,mDownY,y,velocity,(int)minY,(int)maxY,mOverscrollSize);
  mSv.invalidate();
}
mSv.resetFocusedTask(mSv.getFocusedTask());
}
 else if (mActiveTaskView == null) {
maybeHideRecentsFromBackgroundTap((int)ev.getX(),(int)ev.getY());
}
mActivePointerId=INACTIVE_POINTER_ID;
mIsScrolling=false;
recycleVelocityTracker();
break;
}
case MotionEvent.ACTION_CANCEL:
{
mActivePointerId=INACTIVE_POINTER_ID;
mIsScrolling=false;
recycleVelocityTracker();
break;
}
}
return mIsScrolling;
}

Fixed version (ground truth):
private boolean handleTouchEvent(MotionEvent ev){
  if (mSv.getTaskViews().size() == 0) {
    return false;
  }
  final TaskStackLayoutAlgorithm layoutAlgorithm=mSv.mLayoutAlgorithm;
  int action=ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
{
      mDownX=(int)ev.getX();
      mDownY=(int)ev.getY();
      mLastY=mDownY;
      mDownScrollP=mScroller.getStackScroll();
      mActivePointerId=ev.getPointerId(0);
      mActiveTaskView=findViewAtPoint(mDownX,mDownY);
      mScroller.stopScroller();
      mScroller.stopBoundScrollAnimation();
      mScroller.resetDeltaScroll();
      Utilities.cancelAnimationWithoutCallbacks(mScrollFlingAnimator);
      mSv.cancelAllTaskViewAnimations();
      ArrayMap<View,Animator> existingAnimators=new ArrayMap<>(mSwipeHelperAnimations);
      for (int i=0; i < existingAnimators.size(); i++) {
        existingAnimators.get(existingAnimators.keyAt(i)).end();
      }
      mSwipeHelperAnimations.clear();
      initOrResetVelocityTracker();
      mVelocityTracker.addMovement(ev);
      break;
    }
case MotionEvent.ACTION_POINTER_DOWN:
{
    final int index=ev.getActionIndex();
    mActivePointerId=ev.getPointerId(index);
    mDownX=(int)ev.getX(index);
    mDownY=(int)ev.getY(index);
    mLastY=mDownY;
    mDownScrollP=mScroller.getStackScroll();
    mScroller.resetDeltaScroll();
    mVelocityTracker.addMovement(ev);
    break;
  }
case MotionEvent.ACTION_MOVE:
{
  int activePointerIndex=ev.findPointerIndex(mActivePointerId);
  int y=(int)ev.getY(activePointerIndex);
  int x=(int)ev.getX(activePointerIndex);
  if (!mIsScrolling) {
    int yDiff=Math.abs(y - mDownY);
    int xDiff=Math.abs(x - mDownX);
    if (Math.abs(y - mDownY) > mScrollTouchSlop && yDiff > xDiff) {
      mIsScrolling=true;
      float stackScroll=mScroller.getStackScroll();
      List<TaskView> taskViews=mSv.getTaskViews();
      for (int i=taskViews.size() - 1; i >= 0; i--) {
        layoutAlgorithm.addUnfocusedTaskOverride(taskViews.get(i).getTask(),stackScroll);
      }
      layoutAlgorithm.setFocusState(TaskStackLayoutAlgorithm.STATE_UNFOCUSED);
      final ViewParent parent=mSv.getParent();
      if (parent != null) {
        parent.requestDisallowInterceptTouchEvent(true);
      }
      MetricsLogger.action(mSv.getContext(),MetricsEvent.OVERVIEW_SCROLL);
    }
  }
  if (mIsScrolling) {
    float deltaP=layoutAlgorithm.getDeltaPForY(mDownY,y);
    float minScrollP=layoutAlgorithm.mMinScrollP;
    float maxScrollP=layoutAlgorithm.mMaxScrollP;
    float curScrollP=mDownScrollP + deltaP;
    if (curScrollP < minScrollP || curScrollP > maxScrollP) {
      float clampedScrollP=Utilities.clamp(curScrollP,minScrollP,maxScrollP);
      float overscrollP=(curScrollP - clampedScrollP);
      float overscrollX=Math.abs(overscrollP) / MAX_OVERSCROLL;
      float interpX=OVERSCROLL_INTERP.getInterpolation(overscrollX);
      curScrollP=clampedScrollP + Math.signum(overscrollP) * (interpX * MAX_OVERSCROLL);
    }
    mDownScrollP+=mScroller.setDeltaStackScroll(mDownScrollP,curScrollP - mDownScrollP);
    mStackViewScrolledEvent.updateY(y - mLastY);
    EventBus.getDefault().send(mStackViewScrolledEvent);
  }
  mLastY=y;
  mVelocityTracker.addMovement(ev);
  break;
}
case MotionEvent.ACTION_POINTER_UP:
{
int pointerIndex=ev.getActionIndex();
int pointerId=ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
  final int newPointerIndex=(pointerIndex == 0) ? 1 : 0;
  mActivePointerId=ev.getPointerId(newPointerIndex);
  mDownX=(int)ev.getX(pointerIndex);
  mDownY=(int)ev.getY(pointerIndex);
  mLastY=mDownY;
  mDownScrollP=mScroller.getStackScroll();
}
mVelocityTracker.addMovement(ev);
break;
}
case MotionEvent.ACTION_UP:
{
mVelocityTracker.addMovement(ev);
mVelocityTracker.computeCurrentVelocity(1000,mMaximumVelocity);
int activePointerIndex=ev.findPointerIndex(mActivePointerId);
int y=(int)ev.getY(activePointerIndex);
int velocity=(int)mVelocityTracker.getYVelocity(mActivePointerId);
if (mIsScrolling) {
if (mScroller.isScrollOutOfBounds()) {
  mScroller.animateBoundScroll();
}
 else if (Math.abs(velocity) > mMinimumVelocity) {
  float minY=mDownY + layoutAlgorithm.getYForDeltaP(mDownScrollP,layoutAlgorithm.mMaxScrollP);
  float maxY=mDownY + layoutAlgorithm.getYForDeltaP(mDownScrollP,layoutAlgorithm.mMinScrollP);
  mScroller.fling(mDownScrollP,mDownY,y,velocity,(int)minY,(int)maxY,mOverscrollSize);
  mSv.invalidate();
}
mSv.resetFocusedTask(mSv.getFocusedTask());
}
 else if (mActiveTaskView == null) {
maybeHideRecentsFromBackgroundTap((int)ev.getX(),(int)ev.getY());
}
mActivePointerId=INACTIVE_POINTER_ID;
mIsScrolling=false;
recycleVelocityTracker();
break;
}
case MotionEvent.ACTION_CANCEL:
{
mActivePointerId=INACTIVE_POINTER_ID;
mIsScrolling=false;
recycleVelocityTracker();
break;
}
}
return mIsScrolling;
}