DM-54947: Fix assembleCellCoadd handling of fully-masked cells

python/lsst/cell_coadds/_coadd_ap_corr_map.py

@@ -101,6 +101,12 @@ def _setup_ap_corr_names(self, ap_corr_map: ApCorrMap) -> None:
 
         self._ap_corr_names = tuple(sorted(ap_corr_name_set))
 
+    def reset(self) -> None:
+        """Reset to the post-initialization state."""
+        self._total_weight = 0.0
+        self._intermediate_ap_corr_map = {}
+        self._ap_corr_names = ()
+
     @property
     def evaluation_point(self) -> Point2D:
         """The point at which the aperture correction is evaluated."""

python/lsst/cell_coadds/_fits.py

@@ -114,7 +114,7 @@
 from ._uniform_grid import UniformGrid
 from .typing_helpers import SingleCellCoaddApCorrMap
 
-FILE_FORMAT_VERSION = "0.8"
+FILE_FORMAT_VERSION = "0.9"
 """Version number for the file format as persisted, presented as a string of
 the form M.m, where M is the major version, m is the minor version.
 """
@@ -301,6 +301,7 @@ def readAsMultipleCellCoadd(self) -> MultipleCellCoadd:
             coadd_input = CoaddInputs(  # default version for written_version <= 0.5.
                 overlaps_center=True,
                 overlap_fraction=1.0,
+                unmasked_overlap_fraction=1.0,
                 weight=0.0,
                 psf_shape=afwGeom.Quadrupole(),
                 psf_shape_flag=True,
@@ -373,6 +374,11 @@ def readAsMultipleCellCoadd(self) -> MultipleCellCoadd:
                         coadd_input = CoaddInputs(
                             overlaps_center=link_row["overlaps_center"],
                             overlap_fraction=link_row["overlap_fraction"],
+                            unmasked_overlap_fraction=(
+                                link_row["unmasked_overlap_fraction"]
+                                if written_version >= version.parse("0.9")
+                                else link_row["overlap_fraction"]
+                            ),
                             weight=link_row["weight"],
                             psf_shape=afwGeom.Quadrupole(
                                 ixx=link_row["psf_shape_ixx"],
@@ -674,6 +680,7 @@ def writeMultipleCellCoaddAsFits(
                     observation_id.detector,
                     coadd_input.overlaps_center,
                     coadd_input.overlap_fraction,
+                    coadd_input.unmasked_overlap_fraction,
                     coadd_input.weight,
                     coadd_input.psf_shape.getIxx(),
                     coadd_input.psf_shape.getIyy(),
@@ -769,6 +776,7 @@ def writeMultipleCellCoaddAsFits(
             "detector",
             "overlaps_center",
             "overlap_fraction",
+            "unmasked_overlap_fraction",
             "weight",
             "psf_shape_ixx",
             "psf_shape_iyy",

python/lsst/cell_coadds/_single_cell_coadd.py

@@ -49,12 +49,16 @@ class CoaddInputs:
     """Container for inputs to the coaddition process."""
 
     overlaps_center: bool
-    """Whether a single (detector, visit) observation overlaps the center """
-    """of the cell."""
+    """Whether a single (detector, visit) observation overlaps the center
+    of the cell."""
 
     overlap_fraction: float
     """Fraction of the cell that is covered by the overlap region."""
 
+    unmasked_overlap_fraction: float
+    """Fraction of the cell covered by this detector, excluding
+    rejected pixels."""
+
     weight: float
     """Weight to be used for this input."""
 
@@ -119,7 +123,15 @@ def __init__(
         self._inputs: Mapping[ObservationIdentifiers, CoaddInputs]
         if inputs:
             self._inputs = dict.fromkeys(
-                sorted(set(inputs)), CoaddInputs(False, 0.0, 0.0, Quadrupole(), True)
+                sorted(set(inputs)),
+                CoaddInputs(
+                    overlaps_center=False,
+                    overlap_fraction=0.0,
+                    unmasked_overlap_fraction=0.0,
+                    weight=0.0,
+                    psf_shape=Quadrupole(),
+                    psf_shape_flag=True,
+                ),
             )
             self._inputs.update(inputs)
         else:

tests/test_coadds.py

@@ -263,14 +263,15 @@ def setUpClass(cls) -> None:
                                 detector=67,
                                 day_obs=20000101,
                             ): CoaddInputs(
-                                True,
-                                1.0,
-                                1.0,
-                                Quadrupole(
+                                overlaps_center=True,
+                                overlap_fraction=1.0,
+                                unmasked_overlap_fraction=1.0,
+                                weight=1.0,
+                                psf_shape=Quadrupole(
                                     cls.psf_sigmas[Index2D(x=x, y=y)] ** 2,
                                     cls.psf_sigmas[Index2D(x=x, y=y)] ** 2,
                                 ),
-                                False,
+                                psf_shape_flag=False,
                             )
                         },
                         common=common,