Document that certain faro steps now need a band constraint.

When a task has band in its quantum dimensions but does not have band
in the dimensions of any of its inputs, it will run over all bands
known to any instrument unless those bands are constrained by the data
query.  It was an accident of the old QG generation algorithm that this
wasn't happening before (unrelated tasks in the same step were
providing a band constraint, but the middleware now sees them as
unrelated).

pipelines/HSC/DRP-RC2_subset.yaml

@@ -400,10 +400,11 @@ subsets:
       - skyObjectStd
     description: >
       Tasks that can be run together, but only after the 'step1', 'step2',
-      'step3', and 'step4' subsets
+      'step3', and 'step4' subsets.
       This step includes patch-level aggregation Tasks. These should be
-      run with explicit 'tract' constraints in the data query, otherwise
-      quanta will be created for jobs with only partial visit coverage.
+      run with explicit 'tract' and 'band' constraints in the data query, or
+      quanta will be created for jobs with only partial visit coverage and
+      for bands with no columns in the object table.
   nightlyStep8:
     subset:
       - validateObjectTableCore

pipelines/_ingredients/HSC/DRP.yaml

@@ -72,3 +72,8 @@ subsets:
     description: |
       Set of tract-level faro metrics to be run on coadd products. These use Object
       Tables which are available after consolidateObjectTable (step3) is run.
+
+      These must have a band constraint in their data query to avoid generating
+      quanta for bands that do not have columns in the object table, since
+      using an object table dataset as input does not provide information to
+      the middleware about which tasks went into making the object table.

pipelines/_ingredients/LSSTCam-imSim/DRP.yaml

@@ -300,3 +300,8 @@ subsets:
     description: |
       Set of tract-level faro metrics to be run on coadd products. These use Object
       Tables which are available after consolidateObjectTable (step3) is run.
+
+      These must have a band constraint in their data query to avoid generating
+      quanta for bands that do not have columns in the object table, since
+      using an object table dataset as input does not provide information to
+      the middleware about which tasks went into making the object table.