filter key handler fixup

python/lsst/obs/base/gen2to3/translators.py

@@ -20,7 +20,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 __all__ = ("Translator", "KeyHandler", "CopyKeyHandler", "ConstantKeyHandler",
-           "CalibKeyHandler", "AbstractFilterKeyHandler",
+           "CalibKeyHandler", "AbstractToPhysicalFilterKeyHandler", "PhysicalToAbstractFilterKeyHandler",
            "makeCalibrationLabel")
 
 import itertools
@@ -228,8 +228,13 @@ def extract(self, gen2id: dict, skyMap: Optional[BaseSkyMap], skyMapName: Option
                                     ccd=gen2id.get(self.ccdKey), filter=gen2id.get("filter"))
 
 
-class AbstractFilterKeyHandler(KeyHandler):
-    """KeyHandler for filter keys that should be mapped to AbstractFilters.
+class PhysicalToAbstractFilterKeyHandler(KeyHandler):
+    """KeyHandler for gen2 ``filter`` keys that match ``physical_filter``
+    keys in gen3 but should be mapped to ``abstract_filter``.
+
+    Note that multiple physical filter can potentially map to one abstract
+    filter, so be careful to only use this translator on obs packages where
+    there is a one-to-one mapping.
     """
 
     __slots__ = ("_map",)
@@ -244,8 +249,13 @@ def extract(self, gen2id, *args, **kwargs):
         return self._map.get(physical, physical)
 
 
-class PhysicalFilterKeyHandler(KeyHandler):
-    """KeyHandler for filter keys that should be mapped to AbstractFilters.
+class AbstractToPhysicalFilterKeyHandler(KeyHandler):
+    """KeyHandler for gen2 ``filter`` keys that match ``abstract_filter``
+    keys in gen3 but should be mapped to ``physical_filter``.
+
+    Note that one abstract filter can potentially map to multiple physical
+    filters, so be careful to only use this translator on obs packages where
+    there is a one-to-one mapping.
     """
 
     __slots__ = ("_map",)
@@ -256,8 +266,8 @@ def __init__(self, filterDefinitions):
                      if d.abstract_filter is not None}
 
     def extract(self, gen2id, *args, **kwargs):
-        filter = gen2id["filter"]
-        return self._map.get(filter, filter)
+        abstract = gen2id["filter"]
+        return self._map.get(abstract, abstract)
 
 
 class Translator: