Program: 86233
Project: 86233
Buggy source:
public void expand(final int position){
  if (isExpanded()) {
    if (expandedPosition != position) {
      collapse(new CompleteListener(){
        @Override public void onComplete(){
          expand(position);
        }
      }
);
    }
    return;
  }
  for (int i=0; i < position; i++) {
    llUpper.addView(getView(i,llUpper));
    if (i < position - 1)     addSeparator(llUpper);
  }
  final View expandedView=getView(position,expandedCard);
  expandView(position,expandedView);
  expandedCard.addView(expandedView);
  for (int i=position + 1; i < getCount(); i++) {
    llLower.addView(getView(i,llLower));
    if (i < getCount() - 1)     addSeparator(llLower);
  }
  final float lowerPos;
  if (position + 1 < getCount()) {
    lowerPos=ViewHelper.getY(views.get(position + 1)) + context.getResources().getDimensionPixelSize(R.dimen.card_topbottom_margin_default);
  }
 else   lowerPos=-1;
  final float mainPos=ViewHelper.getY(views.get(position)) - mainCard.getPaddingTop();
  unexpandedHeight=views.get(position).getHeight();
  if (interceptor != null)   interceptor.beforeExpand(views.get(position));
  new Handler().postDelayed(new Runnable(){
    @Override public void run(){
      if (position != 0)       upperCard.setVisibility(View.VISIBLE);
      if (lowerPos > 0)       lowerCard.setVisibility(View.VISIBLE);
      expandedCard.setVisibility(View.VISIBLE);
      mainCard.setVisibility(View.GONE);
      final int previousHeight=layout.getHeight();
      layout.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener(){
        @Override public boolean onPreDraw(){
          int newHeight=layout.getHeight();
          heightDifference=newHeight - previousHeight;
          layout.getViewTreeObserver().removeOnPreDrawListener(this);
          if (lowerPos > 0)           ViewHelper.setY(lowerCard,lowerPos);
          ViewHelper.setY(expandedCard,mainPos);
          lowerTranslationY=ViewHelper.getTranslationY(lowerCard);
          expandedTranslationY=ViewHelper.getTranslationY(expandedCard);
          AnimatorSet set=new AnimatorSet();
          int defaultMargin=context.getResources().getDimensionPixelSize(R.dimen.card_side_margin_default);
          int expandedMargin=context.getResources().getDimensionPixelSize(R.dimen.card_side_margin_selected);
          int marginDifference=expandedMargin - defaultMargin;
          List<Animator> animators=new ArrayList<>();
          addAll(animators,ObjectAnimator.ofFloat(lowerCard,"String_Node_Str",ViewHelper.getTranslationY(lowerCard),0),ObjectAnimator.ofFloat(expandedCard,"String_Node_Str",ViewHelper.getTranslationY(expandedCard),0),ObjectAnimator.ofFloat(expandedCard,"String_Node_Str",context.getResources().getDimension(R.dimen.card_elevation_default),context.getResources().getDimension(R.dimen.card_elevation_selected)),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getBottom() + unexpandedHeight - expandedView.getHeight(),expandedCard.getBottom()),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getLeft() - marginDifference,expandedCard.getLeft()),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getRight() + marginDifference,expandedCard.getRight()));
          if (interceptor != null) {
            animators.addAll(interceptor.getExpandAnimations(heightDifference,expandedView));
          }
          set.playTogether(animators);
          set.setDuration(ANIMATION_DURATION).start();
          return false;
        }
      }
);
      expandedPosition=position;
    }
  }
,100);
}

Fixed version (ground truth):
public void expand(final int position){
  if (isExpanded()) {
    if (expandedPosition != position) {
      collapse(new CompleteListener(){
        @Override public void onComplete(){
          expand(position);
        }
      }
);
    }
    return;
  }
  resetViews();
  for (int i=0; i < position; i++) {
    llUpper.addView(getView(i,llUpper));
    if (i < position - 1)     addSeparator(llUpper);
  }
  final View expandedView=getView(position,expandedCard);
  expandView(position,expandedView);
  expandedCard.addView(expandedView);
  for (int i=position + 1; i < getCount(); i++) {
    llLower.addView(getView(i,llLower));
    if (i < getCount() - 1)     addSeparator(llLower);
  }
  final float lowerPos;
  if (position + 1 < getCount()) {
    lowerPos=ViewHelper.getY(views.get(position + 1)) + context.getResources().getDimensionPixelSize(R.dimen.card_topbottom_margin_default);
  }
 else   lowerPos=-1;
  final float mainPos=ViewHelper.getY(views.get(position)) - mainCard.getPaddingTop();
  unexpandedHeight=views.get(position).getHeight();
  if (interceptor != null)   interceptor.beforeExpand(views.get(position));
  new Handler().postDelayed(new Runnable(){
    @Override public void run(){
      if (position != 0)       upperCard.setVisibility(View.VISIBLE);
      if (lowerPos > 0)       lowerCard.setVisibility(View.VISIBLE);
      expandedCard.setVisibility(View.VISIBLE);
      mainCard.setVisibility(View.GONE);
      final int previousHeight=layout.getHeight();
      layout.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener(){
        @Override public boolean onPreDraw(){
          int newHeight=layout.getHeight();
          heightDifference=newHeight - previousHeight;
          layout.getViewTreeObserver().removeOnPreDrawListener(this);
          if (lowerPos > 0)           ViewHelper.setY(lowerCard,lowerPos);
          ViewHelper.setY(expandedCard,mainPos);
          lowerTranslationY=ViewHelper.getTranslationY(lowerCard);
          expandedTranslationY=ViewHelper.getTranslationY(expandedCard);
          AnimatorSet set=new AnimatorSet();
          int defaultMargin=context.getResources().getDimensionPixelSize(R.dimen.card_side_margin_default);
          int expandedMargin=context.getResources().getDimensionPixelSize(R.dimen.card_side_margin_selected);
          int marginDifference=expandedMargin - defaultMargin;
          List<Animator> animators=new ArrayList<>();
          addAll(animators,ObjectAnimator.ofFloat(lowerCard,"String_Node_Str",ViewHelper.getTranslationY(lowerCard),0),ObjectAnimator.ofFloat(expandedCard,"String_Node_Str",ViewHelper.getTranslationY(expandedCard),0),ObjectAnimator.ofFloat(expandedCard,"String_Node_Str",context.getResources().getDimension(R.dimen.card_elevation_default),context.getResources().getDimension(R.dimen.card_elevation_selected)),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getBottom() + unexpandedHeight - expandedView.getHeight(),expandedCard.getBottom()),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getLeft() - marginDifference,expandedCard.getLeft()),ObjectAnimator.ofInt(expandedCard,"String_Node_Str",expandedCard.getRight() + marginDifference,expandedCard.getRight()));
          if (interceptor != null) {
            animators.addAll(interceptor.getExpandAnimations(heightDifference,expandedView));
          }
          set.playTogether(animators);
          set.setDuration(ANIMATION_DURATION).start();
          return false;
        }
      }
);
      expandedPosition=position;
    }
  }
,100);
}