Metacal flags are nonzero whenever a type has no measured shear, using ngmix's own bits

astra.yaml

@@ -1955,15 +1955,18 @@ analyses:
         rationale: >-
           [HARDCODED] detections with no ngmix row (no surviving epoch, or an
           exception during the fit) stay in the catalogue with sentinels:
-          sizes, fluxes, magnitudes and flags 0, flux and magnitude errors -1,
+          sizes, fluxes and magnitudes 0, flux and magnitude errors -1,
           ellipticities and their errors -10, size errors 1e30,
-          NGMIX_N_EPOCH 0. A failed object's NGMIX_MCAL_FLAGS reads 0, the
-          success value, so a cut on flags alone keeps it; NGMIX_N_EPOCH > 0
-          removes it.
+          NGMIX_N_EPOCH 0. Their flag columns carry ngmix's own
+          LM_FUNC_NOTFINITE bit (2**12; FLAGS_<SHEAR> and NGMIX_MCAL_FLAGS)
+          and NGMIX_MCAL_TYPES_FAIL is 5, as for a metacal type that reports
+          success without a finite shear, so the MCAL_FLAGS == 0 and
+          MCAL_TYPES_FAIL == 0 cut rejects them; NGMIX_N_EPOCH == 0 tells
+          them apart from fitted objects.
         default: sentinel_values
         options:
           sentinel_values:
-            label: Keep with sentinels (flags 0, e -10, T_ERR 1e30)
+            label: Keep with sentinels (flags LM_FUNC_NOTFINITE, e -10, T_ERR 1e30)
           drop_unmatched:
             label: Drop objects without shapes
             excluded: true

src/shapepipe/modules/make_cat_package/make_cat.py

@@ -15,6 +15,11 @@
 from astropy.wcs import WCS
 from sqlitedict import SqliteDict
 
+from shapepipe.modules.ngmix_package.ngmix import (
+    get_mcal_flags,
+    get_mcal_types_fail,
+    get_type_flags,
+)
 from shapepipe.pipeline import file_io
 from shapepipe.utilities import mask_query
 
@@ -423,11 +428,16 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
             If True, write the parallel ``NGMIXm_*`` (moments-branch) columns.
 
         @sc [decision:catalogue_assembly.failure_sentinels,label:coupling] failure-sentinel-cut-semantics
-        Missing-row ``T``, ``SNR``, flux, magnitude, PSF-size and flag values
-        initialize to 0, which is in range and cannot identify failure. Use
-        ``NGMIX_N_EPOCH == 0`` for that cut; the -10 ellipticity, -1
-        flux/magnitude-error and 1e30 size-error sentinels are out of range and
-        can also identify missing fits.
+        An object absent from the ngmix catalogue was never fit (no usable
+        epoch, or its fit raised). Its flag columns take what
+        :func:`ngmix.get_type_flags` derives for an empty metacal result:
+        ``LM_FUNC_NOTFINITE`` in ``FLAGS_<SHEAR>`` and ``MCAL_FLAGS``, and
+        ``MCAL_TYPES_FAIL`` 5, never 0, so sp_validation's ``MCAL_FLAGS == 0``
+        and ``MCAL_TYPES_FAIL == 0`` cut rejects it. Its ``T``, ``SNR``, flux,
+        magnitude and PSF-size values initialize to 0, which is in range and
+        cannot identify failure; ``NGMIX_N_EPOCH == 0`` identifies a
+        never-fit row, and the -10 ellipticity, -1 flux/magnitude-error and
+        1e30 size-error sentinels are out of range.
 
         """
         self._key_ends = ["1M", "1P", "2M", "2P", "NOSHEAR"]
@@ -462,13 +472,19 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
         n_obj = len(self._obj_id)
         self._w_log.info(f"writing ngmix info for {n_obj} objects")
 
+        # An object ngmix never fit has no metacal result at all.
+        never_fit = {}
+
         if moments:
             m = "m"
         else:
             m = ""
 
             self._add2dict("NGMIX_N_EPOCH", np.zeros(n_obj))
-            self._add2dict("NGMIX_MCAL_TYPES_FAIL", np.zeros(n_obj))
+            self._add2dict(
+                "NGMIX_MCAL_TYPES_FAIL",
+                np.full(n_obj, get_mcal_types_fail(never_fit), dtype=float),
+            )
             self._add2dict("NGMIX_NEIGHBOUR_FLAG", np.zeros(n_obj))
 
         prefix = f"NGMIX{m}"
@@ -477,18 +493,22 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
         # reconvolution kernel (PSF_RECONV); see ngmix.average_original_psf /
         # average_multiepoch_psf for what each PSF family is. G1/G2 are scalar
         # reduced-shear components, not a 2-vector. Sentinels:
-        # sizes/fluxes/mags/flags 0, *_ERR fluxes/mags -1, ellipticities -10,
-        # *_ERR sizes 1e30.
+        # sizes/fluxes/mags 0, *_ERR fluxes/mags -1, ellipticities -10,
+        # *_ERR sizes 1e30; flags as ngmix derives for an empty metacal result
+        # (never_fit).
         for key_str in (
             f"{prefix}_T_",
             f"{prefix}_SNR_",
             f"{prefix}_FLUX_",
             f"{prefix}_MAG_",
-            f"{prefix}_FLAGS_",
             f"{prefix}_T_PSF_ORIG_",
             f"{prefix}_T_PSF_RECONV_",
         ):
             self._update_dict(key_str, np.zeros(n_obj))
+        self._update_dict(
+            f"{prefix}_FLAGS_",
+            np.full(n_obj, get_type_flags(never_fit), dtype=float),
+        )
         for key_str in (
             f"{prefix}_FLUX_ERR_",
             f"{prefix}_MAG_ERR_",
@@ -515,7 +535,10 @@ def _save_ngmix_data(self, ngmix_cat_path, moments=False):
             f"{prefix}_T_ERR_PSF_RECONV_",
         ):
             self._update_dict(key_str, np.ones(n_obj) * 1e30)
-        self._add2dict(f"{prefix}_MCAL_FLAGS", np.zeros(n_obj))
+        self._add2dict(
+            f"{prefix}_MCAL_FLAGS",
+            np.full(n_obj, get_mcal_flags(never_fit), dtype=float),
+        )
 
         for idx, id_tmp in enumerate(self._obj_id):
             ind = np.where(id_tmp == ngmix_id)[0]