astropy/astropy — pull request #2796 by AnthonyHorton (2014-07-25 05:24:37+00:00)
Title: Add check for np.ma.nomask in NDData mask setter

Adds a check for a passed value of `np.ma.nomask` in the NDData mask setter. This prevents a `ValueError` being raised when passing a numpy masked array which has no masked entries to `NDData()` (issue #2784).