Create a masked record array if any of the columns are masked

python/lsst/daf/butler/formatters/parquet.py

@@ -231,21 +231,28 @@ def arrow_to_numpy(arrow_table: pa.Table) -> np.ndarray:
     -------
     array : `numpy.ndarray` (N,)
         Numpy array table with N rows and the same column names
-        as the input arrow table.
+        as the input arrow table. Will be masked records if any values
+        in the table are null.
     """
     import numpy as np
 
     numpy_dict = arrow_to_numpy_dict(arrow_table)
 
+    has_mask = False
     dtype = []
     for name, col in numpy_dict.items():
         if len(shape := numpy_dict[name].shape) <= 1:
             dtype.append((name, col.dtype))
         else:
             dtype.append((name, (col.dtype, shape[1:])))
 
-    array = np.rec.fromarrays(numpy_dict.values(), dtype=dtype)
+        if not has_mask and isinstance(col, np.ma.MaskedArray):
+            has_mask = True
 
+    if has_mask:
+        array = np.ma.mrecords.fromarrays(numpy_dict.values(), dtype=dtype)
+    else:
+        array = np.rec.fromarrays(numpy_dict.values(), dtype=dtype)
     return array