Use multiclass of uint32 and Enum rather than IntEnum (#402)

changes/402.misc.rst

@@ -0,0 +1,2 @@
+Use multiclass of `np.uint32` and `Enum` rather than a subclass of `IntEnum` for
+the dqflags as suggested by the numpy devs.

src/roman_datamodels/dqflags.py

@@ -19,12 +19,14 @@
 the formula `2**bit_number` where `bit_number` is the 0-index bit of interest.
 """
 
-from enum import IntEnum, unique
+from enum import Enum, unique
+
+import numpy as np
 
 
 # fmt: off
 @unique
-class pixel(IntEnum):
+class pixel(np.uint32, Enum):
     """Pixel-specific data quality flags"""
 
     GOOD             = 0      # No bits set, all is good
@@ -62,7 +64,7 @@ class pixel(IntEnum):
 
 
 @unique
-class group(IntEnum):
+class group(np.uint32, Enum):
     """Group-specific data quality flags
         Once groups are combined, these flags are equivalent to the pixel-specific flags.
     """

tests/test_dqflags.py

@@ -1,5 +1,6 @@
 from math import log10
 
+import numpy as np
 import pytest
 
 from roman_datamodels import datamodels as rdm
@@ -30,7 +31,7 @@ def test_pixel_flags(flag):
     assert isinstance(flag, dqflags.pixel)
 
     # Test that the pixel flags are ints
-    assert isinstance(flag, int)
+    assert isinstance(flag, np.uint32)
 
     # Test that the pixel flags are dict accessible
     assert dqflags.pixel[flag.name] is flag
@@ -78,7 +79,7 @@ def test_group_flags(flag):
     assert isinstance(flag, dqflags.group)
 
     # Test that the group flags are ints
-    assert isinstance(flag, int)
+    assert isinstance(flag, np.uint32)
 
     # Test that the group flags are dict accessible
     assert dqflags.group[flag.name] is flag