Add requireFiniteRaDec clause to source selector

We are now persisting source catalogs even in light of an astrometric
failure in single frame processing.  Such catalogs will have their sky
coordinate column (typically "coord_ra" and "coord_dec") values set to
NaN.  They are thus not suitable for inclusion in the jointcal
calibration, so this config default ensures they are omited from the
selection of "good" sources.

python/lsst/jointcal/jointcal.py

@@ -533,6 +533,9 @@ def setDefaults(self):
                     f"{self.sourceFluxType}_flag",
                     ]
         self.sourceSelector["science"].flags.bad = badFlags
+        self.sourceSelector["science"].doRequireFiniteRaDec = True
+        self.sourceSelector["science"].requireFiniteRaDec.raColName = "ra"
+        self.sourceSelector["science"].requireFiniteRaDec.decColName = "decl"
 
         # Use Gaia-DR2 with proper motions for astrometry; phot_g_mean is the
         # primary Gaia band, but is not like any normal photometric band.
@@ -799,6 +802,8 @@ def _load_data(self, inputSourceTableVisit, inputVisitSummary, associations,
                 visitCatalog = dataRef.get(parameters={'columns': columns})
 
                 selected = self.sourceSelector.run(visitCatalog)
+                if len(selected) == 0:
+                    raise RuntimeError("No data to process: the source selector removed all sources")
 
                 # Build a CcdImage for each detector in this visit.
                 detectors = {id: index for index, id in enumerate(visitSummary['id'])}
@@ -1604,6 +1609,9 @@ def get_sourceTable_visit_columns(inColumns, config, sourceSelector):
     if sourceSelector.config.doIsolated:
         columns.append(sourceSelector.config.isolated.parentName)
         columns.append(sourceSelector.config.isolated.nChildName)
+    if sourceSelector.config.doRequireFiniteRaDec:
+        columns.append(sourceSelector.config.requireFiniteRaDec.raColName)
+        columns.append(sourceSelector.config.requireFiniteRaDec.decColName)
 
     return columns, detectorColumn, ixxColumns