pydata/pandas — pull request #2686 by jreback (2013-01-11 16:44:55+00:00)
Title: BUG: series assignment with a boolean indexer AND a series as a value would give incorrect results

```
In [1]: import numpy as np

In [2]: import pandas as pd

In [3]: x = pd.Series(index=np.arange(10))

In [4]: y = pd.Series(np.random.rand(10),index=np.arange(10))

In [5]: y
Out[5]:
0 0.197830
1 0.134425
2 0.766618
3 0.057765
4 0.790927
5 0.153636
6 0.585305
7 0.906787
8 0.647155
9 0.494154

In [6]: x[y>0.5] = y

In [7]: x
Out[7]:
0 NaN
1 NaN
2 0.197830
3 NaN
4 0.134425
5 NaN
6 0.766618
7 0.057765
8 0.790927
9 NaN
```