Program: 26939
Project: 26939
Buggy source:
@Override protected void drawData(){
  BarData bd=(BarData)mCurrentData;
  ArrayList<BarDataSet> dataSets=(ArrayList<BarDataSet>)bd.getDataSets();
  int setCount=bd.getDataSetCount();
  for (int i=0; i < setCount; i++) {
    BarDataSet dataSet=dataSets.get(i);
    boolean noStacks=dataSet.getStackSize() == 1 ? true : false;
    ArrayList<BarEntry> entries=(ArrayList<BarEntry>)dataSet.getYVals();
    float spaceSum=bd.getGroupSpace() / 2f;
    for (int j=0; j < dataSet.getEntryCount() * mPhaseX; j++) {
      BarEntry e=entries.get(j);
      float x=e.getXIndex() + j * (setCount - 1) + i + spaceSum;
      float y=e.getVal();
      spaceSum+=bd.getGroupSpace();
      if (noStacks) {
        prepareBar(x,y,dataSet.getBarSpace());
        if (isOffContentRight(mBarRect.left))         break;
        if (isOffContentLeft(mBarRect.right)) {
          continue;
        }
        if (mDrawBarShadow) {
          mRenderPaint.setColor(dataSet.getBarShadowColor());
          mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
        }
        mRenderPaint.setColor(dataSet.getColor(j));
        mDrawCanvas.drawRect(mBarRect,mRenderPaint);
      }
 else {
        float[] vals=e.getVals();
        if (vals == null) {
          prepareBar(x,y,dataSet.getBarSpace());
          if (mDrawBarShadow) {
            mRenderPaint.setColor(dataSet.getBarShadowColor());
            mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
          }
          mRenderPaint.setColor(dataSet.getColor(0));
          mDrawCanvas.drawRect(mBarRect,mRenderPaint);
        }
 else {
          float all=e.getVal();
          if (mDrawBarShadow) {
            prepareBar(x,y,dataSet.getBarSpace());
            mRenderPaint.setColor(dataSet.getBarShadowColor());
            mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
          }
          for (int k=0; k < vals.length; k++) {
            all-=vals[k];
            prepareBar(x,vals[k] + all,dataSet.getBarSpace());
            mRenderPaint.setColor(dataSet.getColor(k));
            mDrawCanvas.drawRect(mBarRect,mRenderPaint);
          }
        }
        if (isOffContentRight(mBarRect.left))         break;
      }
    }
  }
}

Fixed version (ground truth):
@Override protected void drawData(){
  BarData bd=(BarData)mCurrentData;
  ArrayList<BarDataSet> dataSets=(ArrayList<BarDataSet>)bd.getDataSets();
  int setCount=bd.getDataSetCount();
  float space=bd.getGroupSpace();
  for (int i=0; i < setCount; i++) {
    BarDataSet dataSet=dataSets.get(i);
    boolean noStacks=dataSet.getStackSize() == 1 ? true : false;
    ArrayList<BarEntry> entries=(ArrayList<BarEntry>)dataSet.getYVals();
    for (int j=0; j < dataSet.getEntryCount() * mPhaseX; j++) {
      BarEntry e=entries.get(j);
      float x=e.getXIndex() + j * (setCount - 1) + i + space * j + space / 2f;
      float y=e.getVal();
      if (noStacks) {
        prepareBar(x,y,dataSet.getBarSpace());
        if (isOffContentRight(mBarRect.left))         break;
        if (isOffContentLeft(mBarRect.right)) {
          continue;
        }
        if (mDrawBarShadow) {
          mRenderPaint.setColor(dataSet.getBarShadowColor());
          mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
        }
        mRenderPaint.setColor(dataSet.getColor(j));
        mDrawCanvas.drawRect(mBarRect,mRenderPaint);
      }
 else {
        float[] vals=e.getVals();
        if (vals == null) {
          prepareBar(x,y,dataSet.getBarSpace());
          if (mDrawBarShadow) {
            mRenderPaint.setColor(dataSet.getBarShadowColor());
            mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
          }
          mRenderPaint.setColor(dataSet.getColor(0));
          mDrawCanvas.drawRect(mBarRect,mRenderPaint);
        }
 else {
          float all=e.getVal();
          if (mDrawBarShadow) {
            prepareBar(x,y,dataSet.getBarSpace());
            mRenderPaint.setColor(dataSet.getBarShadowColor());
            mDrawCanvas.drawRect(mBarShadow,mRenderPaint);
          }
          for (int k=0; k < vals.length; k++) {
            all-=vals[k];
            prepareBar(x,vals[k] + all,dataSet.getBarSpace());
            mRenderPaint.setColor(dataSet.getColor(k));
            mDrawCanvas.drawRect(mBarRect,mRenderPaint);
          }
        }
        if (isOffContentRight(mBarRect.left))         break;
      }
    }
  }
}