printed masked arrays

[ev-br]

DTChecker gets into an infinite loop / hard crash in (observed in np.ma.__init__ docstring)

>>> x = np.array([2, 1, 3, np.nan, 5, 2, 3, np.nan])
>>> m = np.ma.masked_array(x, np.isnan(x))
>>> m
masked_array(data = [2.0 1.0 3.0 -- 5.0 2.0 3.0 --],
      mask = [False False False  True False False False  True],
      fill_value=1e+20)

Note that the data and mask arrays are missing commas.

The issue here is that the detection of a printed array (reinsert commas and retry) only looks at the opening square bracket in the beginning of the string. Thus DTChecker detects it's a masked array, does its .replace(--, 'nan') dance and retries. But data and mask arrays never get their commas reinserted, so the check fails again, detects a masked array and retries again until stopped by a recursion limit.

[ev-br]

Maybe the right thing is to check presence of not only masked_array but also of -- in the DTChecker dance.