Program: 18974
Project: 18974
Buggy source:
@Override protected void drawData(){
  ArrayList<Path> topPaths=new ArrayList<Path>();
  ArrayList<Path> sidePaths=new ArrayList<Path>();
  if (m3DEnabled) {
    float[] pts=new float[]{0f,0f,1f,0f};
    transformPointArray(pts);
    pts[3]=pts[2] - pts[0];
    pts[2]=0f;
    pts[1]=0f;
    pts[0]=0f;
    Matrix invert=new Matrix();
    mMatrixOffset.invert(invert);
    invert.mapPoints(pts);
    mMatrixTouch.invert(invert);
    invert.mapPoints(pts);
    mMatrixValueToPx.invert(invert);
    invert.mapPoints(pts);
    float depth=Math.abs(pts[3] - pts[1]) * mDepth;
    for (int i=0; i < mData.getYValCount(); i++) {
      float y=getYValue(i);
      float left=i + mBarSpace / 2f;
      float right=i + 1f - mBarSpace / 2f;
      float top=y >= 0 ? y : 0;
      Path topPath=new Path();
      topPath.moveTo(left,top);
      topPath.lineTo(left + mSkew,top + depth);
      topPath.lineTo(right + mSkew,top + depth);
      topPath.lineTo(right,top);
      topPaths.add(topPath);
      Path sidePath=new Path();
      sidePath.moveTo(right,top);
      sidePath.lineTo(right + mSkew,top + depth);
      sidePath.lineTo(right + mSkew,depth);
      sidePath.lineTo(right,0);
      sidePaths.add(sidePath);
    }
    transformPaths(topPaths);
    transformPaths(sidePaths);
  }
  ArrayList<DataSet> dataSets=mData.getDataSets();
  for (int i=0; i < mData.getDataSetCount(); i++) {
    DataSet dataSet=dataSets.get(i);
    ArrayList<Series> series=dataSet.getYVals();
    for (int j=0; j < dataSet.getSeriesCount(); j++) {
      Paint paint=mDrawPaints[j % mDrawPaints.length];
      int x=series.get(j).getXIndex();
      float y=series.get(j).getVal();
      float left=x + mBarSpace / 2f;
      float right=x + 1f - mBarSpace / 2f;
      float top=y >= 0 ? y : 0;
      float bottom=y <= 0 ? y : 0;
      mBarRect.set(left,top,right,bottom);
      transformRect(mBarRect);
      mDrawCanvas.drawRect(mBarRect,paint);
      if (m3DEnabled) {
        int c=paint.getColor();
        paint.setColor(mTopColors[j % mTopColors.length]);
        mDrawCanvas.drawPath(topPaths.get(j),paint);
        paint.setColor(mSideColors[j % mSideColors.length]);
        mDrawCanvas.drawPath(sidePaths.get(j),paint);
        paint.setColor(c);
      }
    }
  }
}

Fixed version (ground truth):
@Override protected void drawData(){
  ArrayList<Path> topPaths=new ArrayList<Path>();
  ArrayList<Path> sidePaths=new ArrayList<Path>();
  if (m3DEnabled) {
    float[] pts=new float[]{0f,0f,1f,0f};
    transformPointArray(pts);
    pts[3]=pts[2] - pts[0];
    pts[2]=0f;
    pts[1]=0f;
    pts[0]=0f;
    Matrix invert=new Matrix();
    mMatrixOffset.invert(invert);
    invert.mapPoints(pts);
    mMatrixTouch.invert(invert);
    invert.mapPoints(pts);
    mMatrixValueToPx.invert(invert);
    invert.mapPoints(pts);
    float depth=Math.abs(pts[3] - pts[1]) * mDepth;
    for (int i=0; i < mData.getYValCount(); i++) {
      float y=getYValue(i);
      float left=i + mBarSpace / 2f;
      float right=i + 1f - mBarSpace / 2f;
      float top=y >= 0 ? y : 0;
      Path topPath=new Path();
      topPath.moveTo(left,top);
      topPath.lineTo(left + mSkew,top + depth);
      topPath.lineTo(right + mSkew,top + depth);
      topPath.lineTo(right,top);
      topPaths.add(topPath);
      Path sidePath=new Path();
      sidePath.moveTo(right,top);
      sidePath.lineTo(right + mSkew,top + depth);
      sidePath.lineTo(right + mSkew,depth);
      sidePath.lineTo(right,0);
      sidePaths.add(sidePath);
    }
    transformPaths(topPaths);
    transformPaths(sidePaths);
  }
  ArrayList<DataSet> dataSets=mData.getDataSets();
  for (int i=0; i < mData.getDataSetCount(); i++) {
    DataSet dataSet=dataSets.get(i);
    ArrayList<Series> series=dataSet.getYVals();
    Paint paint=mDrawPaints[i % mDrawPaints.length];
    for (int j=0; j < dataSet.getSeriesCount(); j++) {
      if (mData.getDataSetCount() == 1)       paint=mDrawPaints[j % mDrawPaints.length];
      int x=series.get(j).getXIndex();
      float y=series.get(j).getVal();
      float left=x + mBarSpace / 2f;
      float right=x + 1f - mBarSpace / 2f;
      float top=y >= 0 ? y : 0;
      float bottom=y <= 0 ? y : 0;
      mBarRect.set(left,top,right,bottom);
      transformRect(mBarRect);
      mDrawCanvas.drawRect(mBarRect,paint);
      if (m3DEnabled) {
        int c=paint.getColor();
        paint.setColor(mTopColors[j % mTopColors.length]);
        mDrawCanvas.drawPath(topPaths.get(j),paint);
        paint.setColor(mSideColors[j % mSideColors.length]);
        mDrawCanvas.drawPath(sidePaths.get(j),paint);
        paint.setColor(c);
      }
    }
  }
}