Merge pull request #335 from lsst/tickets/DM-39720

DM-39720: Use default factory for Stamps class
lsst · Jun 20, 2023 · 93864be · 93864be
2 parents 41a93ce + f8ecf2a
commit 93864be
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Showing 2 changed files with 14 additions and 6 deletions.
diff --git a/python/lsst/meas/algorithms/accumulator_mean_stack.py b/python/lsst/meas/algorithms/accumulator_mean_stack.py
@@ -19,6 +19,8 @@
 # the GNU General Public License along with this program.  If not,
 # see <https://www.lsstcorp.org/LegalNotices/>.
 #
+import warnings
+
 import numpy as np
 
 
@@ -133,9 +135,9 @@ def fill_stacked_masked_image(self, stacked_masked_image):
         stacked_masked_image : `lsst.afw.image.MaskedImage`
             Total masked image.
         """
-        with np.warnings.catch_warnings():
+        with warnings.catch_warnings():
             # Let the NaNs through and flag bad pixels below
-            np.warnings.simplefilter("ignore")
+            warnings.simplefilter("ignore")
 
             # The image plane is sum(weight*data)/sum(weight)
             stacked_masked_image.image.array[:, :] = self.sum_wdata/self.sum_weight
@@ -203,10 +205,10 @@ def fill_stacked_image(self, stacked_image):
         stacked_image : `lsst.afw.image.Image`
             Total image.
         """
-        with np.warnings.catch_warnings():
+        with warnings.catch_warnings():
             # Let the NaNs through, this should only happen
             # if we're stacking with no inputs.
-            np.warnings.simplefilter("ignore")
+            warnings.simplefilter("ignore")
 
             # The image plane is sum(weight*data)/sum(weight)
             stacked_image.array[:, :] = self.sum_wdata/self.sum_weight

diff --git a/python/lsst/meas/algorithms/stamps.py b/python/lsst/meas/algorithms/stamps.py
@@ -25,7 +25,7 @@
 
 import abc
 from collections.abc import Sequence
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 
 import numpy as np
 from lsst.afw.fits import Fits, readMetadata
@@ -213,6 +213,12 @@ def factory(cls, stamp_im, metadata, index, archive_element=None):
         raise NotImplementedError
 
 
+def _default_position():
+    # SpherePoint is nominally mutable in C++ so we must use a factory
+    # and return an entirely new SpherePoint each time a Stamps is created.
+    return SpherePoint(Angle(np.nan), Angle(np.nan))
+
+
 @dataclass
 class Stamp(AbstractStamp):
     """Single stamp.
@@ -230,7 +236,7 @@ class Stamp(AbstractStamp):
 
     stamp_im: MaskedImageF
     archive_element: Persistable | None = None
-    position: SpherePoint | None = SpherePoint(Angle(np.nan), Angle(np.nan))
+    position: SpherePoint | None = field(default_factory=_default_position)
 
     @classmethod
     def factory(cls, stamp_im, metadata, index, archive_element=None):