Do not reject saturated sources in SourceSelector.

Per discussion on Slack of 2018-02-05:

> `interpolated`... now effectively means "this pixel was interpolated in one
> of the inputs and that's okay because we think the interpolation was good".

(Jim Bosch, in #subaru-hsc)

We should therefore not reject sources flagged as such in the source selector.

python/lsst/meas/algorithms/sourceSelector.py

@@ -49,7 +49,6 @@ class BaseSourceSelectorConfig(pexConfig.Config):
             "base_PixelFlags_flag_saturatedCenter",
             "base_PixelFlags_flag_crCenter",
             "base_PixelFlags_flag_bad",
-            "base_PixelFlags_flag_interpolated",
         ],
     )
 
@@ -404,8 +403,7 @@ class ScienceSourceSelectorConfig(pexConfig.Config):
 
     def setDefaults(self):
         pexConfig.Config.setDefaults(self)
-        self.flags.bad = ["base_PixelFlags_flag_edge", "base_PixelFlags_flag_interpolated",
-                          "base_PixelFlags_flag_saturated", "base_PsfFlux_flags"]
+        self.flags.bad = ["base_PixelFlags_flag_edge", "base_PixelFlags_flag_saturated", "base_PsfFlux_flags"]
         self.signalToNoise.fluxField = "base_PsfFlux_flux"
         self.signalToNoise.errField = "base_PsfFlux_fluxSigma"
 

tests/test_astrometrySourceSelector.py

@@ -42,11 +42,14 @@
             "base_PixelFlags_flag_saturatedCenter",
             "base_PixelFlags_flag_crCenter",
             "base_PixelFlags_flag_bad",
-            "base_PixelFlags_flag_interpolated",
             "slot_Centroid_flag",
             "slot_ApFlux_flag",
             ]
 
+# goodFlags are flags that should NOT cause the object to be immediately
+# thrown out, despite their possibly ominous-sounding names.
+goodFlags = ["base_PixelFlags_flag_interpolated"]
+
 
 def add_good_source(src, num=0):
     """Insert a likely-good source into the catalog."""
@@ -71,7 +74,7 @@ def setUp(self):
         schema = lsst.meas.base.tests.TestDataset.makeMinimalSchema()
         schema.addField("slot_ApFlux_flux", type=np.float64)
         schema.addField("slot_ApFlux_fluxSigma", type=np.float64)
-        for flag in badFlags:
+        for flag in badFlags + goodFlags:
             schema.addField(flag, type="Flag")
 
         self.src = afwTable.SourceCatalog(schema)
@@ -84,6 +87,8 @@ def tearDown(self):
     def testSelectSources_good(self):
         for i in range(5):
             add_good_source(self.src, i)
+            for flag in goodFlags:
+                self.src[i].set(flag, True)
         result = self.sourceSelector.selectSources(self.src)
         # TODO: assertEqual doesn't work correctly on source catalogs.
         # self.assertEqual(result.sourceCat, self.src)