Use separate classes for the cpCombine step when it does and does not

use the 'physical_filter' dimension.

The new CalibCombineByFilter Connections, Config, and Task now inherit
from their respective CalibCombine counterparts, but simply add the
new dimension.  This avoids the previous work around to have the
dimensions edited on construction.

Update the pipeline definitions for this as well.

pipelines/cpFlat.yaml

@@ -28,13 +28,12 @@ tasks:
       connections.inputMDs: 'flatStats'
       connections.outputScales: 'cpFlatNormScales'
   cpFlatCombine:
-    class: lsst.cp.pipe.cpCombine.CalibCombineTask
+    class: lsst.cp.pipe.cpCombine.CalibCombineByFilterTask
     config:
       connections.inputExps: 'cpFlatProc'
       connections.inputScales: 'cpFlatNormScales'
       connections.outputData: 'flat'
       calibrationType: 'flat'
-      calibrationDimensions: ['physical_filter']
       exposureScaling: InputList
       scalingLevel: AMP
 contracts:

pipelines/cpFlatSingleChip.yaml

@@ -18,12 +18,11 @@ tasks:
       doFringe: False
       doApplyGains: False
   cpFlatCombine:
-    class: lsst.cp.pipe.cpCombine.CalibCombineTask
+    class: lsst.cp.pipe.cpCombine.CalibCombineByFilterTask
     config:
       connections.inputExps: 'cpFlatProc'
       connections.outputData: 'flat'
       calibrationType: 'flat'
-      calibrationDimensions: ['physical_filter']
       exposureScaling: MeanStats
 contracts:
   - isr.doFlat == False

pipelines/cpFringe.yaml

@@ -22,12 +22,11 @@ tasks:
       connections.inputExp: 'cpFringeIsr'
       connections.outputExp: 'cpFringeProc'
   cpFringeCombine:
-    class: lsst.cp.pipe.cpCombine.CalibCombineTask
+    class: lsst.cp.pipe.cpCombine.CalibCombineByFilterTask
     config:
       connections.inputExps: 'cpFringeProc'
       connections.outputData: 'fringe'
       calibrationType: 'fringe'
-      calibrationDimensions: ['physical_filter']
       exposureScaling: "Unity"
 contracts:
   - isr.doFringe == False

python/lsst/cp/pipe/cpCombine.py

@@ -117,34 +117,6 @@ class CalibCombineConnections(pipeBase.PipelineTaskConnections,
         isCalibration=True,
     )
 
-    def __init__(self, *, config=None):
-        super().__init__(config=config)
-
-        if config and config.exposureScaling != 'InputList':
-            self.inputs.discard("inputScales")
-
-        if config and len(config.calibrationDimensions) != 0:
-            newDimensions = tuple(config.calibrationDimensions)
-            newOutputData = cT.Output(
-                name=self.outputData.name,
-                doc=self.outputData.doc,
-                storageClass=self.outputData.storageClass,
-                dimensions=self.allConnections['outputData'].dimensions + newDimensions,
-                isCalibration=True,
-            )
-            self.dimensions.update(config.calibrationDimensions)
-            self.outputData = newOutputData
-
-            if config.exposureScaling == 'InputList':
-                newInputScales = cT.PrerequisiteInput(
-                    name=self.inputScales.name,
-                    doc=self.inputScales.doc,
-                    storageClass=self.inputScales.storageClass,
-                    dimensions=self.allConnections['inputScales'].dimensions + newDimensions
-                )
-                self.dimensions.update(config.calibrationDimensions)
-                self.inputScales = newInputScales
-
 
 # CalibCombineConfig/CalibCombineTask from pipe_base/constructCalibs.py
 class CalibCombineConfig(pipeBase.PipelineTaskConfig,
@@ -156,11 +128,6 @@ class CalibCombineConfig(pipeBase.PipelineTaskConfig,
         default="calibration",
         doc="Name of calibration to be generated.",
     )
-    calibrationDimensions = pexConfig.ListField(
-        dtype=str,
-        default=[],
-        doc="List of updated dimensions to append to output."
-    )
 
     exposureScaling = pexConfig.ChoiceField(
         dtype=str,
@@ -526,6 +493,24 @@ def interpolateNans(self, exp):
             self.log.warn("Found %s NAN pixels", count)
 
 
+# Create versions of the Connections, Config, and Task that support filter constraints.
+class CalibCombineByFilterConnections(CalibCombineConnections,
+                                      dimensions=("instrument", "detector", "physical_filter")):
+    pass
+
+
+class CalibCombineByFilterConfig(CalibCombineConfig,
+                                 pipelineConnections=CalibCombineConnections):
+    pass
+
+
+class CalibCombineByFilterTask(CalibCombineTask):
+    """Task to combine calib exposures."""
+    ConfigClass = CalibCombineFilterConfig
+    _DefaultName = 'cpFilterCombine'
+    pass
+
+
 def VignetteExposure(exposure, polygon=None,
                      doUpdateMask=True, maskPlane='BAD',
                      doSetValue=False, vignetteValue=0.0,