Turn off compatibility mode as the default.

Also set the default convolution mode to `convolveTemplate`

Update subtractImages config validation.

python/lsst/ip/diffim/subtractImages.py

@@ -99,7 +99,7 @@ class AlardLuptonSubtractConfig(lsst.pipe.base.PipelineTaskConfig,
                                 pipelineConnections=AlardLuptonSubtractConnections):
     mode = lsst.pex.config.ChoiceField(
         dtype=str,
-        default="auto",
+        default="convolveTemplate",
         allowed={"auto": "Choose which image to convolve at runtime.",
                  "convolveScience": "Only convolve the science image.",
                  "convolveTemplate": "Only convolve the template image."},
@@ -148,7 +148,7 @@ class AlardLuptonSubtractConfig(lsst.pipe.base.PipelineTaskConfig,
 
     forceCompatibility = lsst.pex.config.Field(
         dtype=bool,
-        default=True,
+        default=False,
         doc="Set up and run diffim using settings that ensure the results"
         "are compatible with the old version in pipe_tasks.",
         deprecated="This option is only for backwards compatibility purposes"
@@ -162,8 +162,8 @@ def setDefaults(self):
         self.makeKernel.kernel.active.spatialBgOrder = 2
 
     def validate(self):
-        if self.forceCompatibility:
-            self.mode = "convolveTemplate"
+        if self.forceCompatibility and not (self.mode == "convolveTemplate"):
+            raise ValueError("If forceCompatibility=True, then mode='convolveTemplate' must also be set")
 
 
 class AlardLuptonSubtractTask(lsst.pipe.base.PipelineTask):

tests/test_subtractTask.py

@@ -252,6 +252,7 @@ def _run_and_check_images(statsCtrl, statsCtrlDetect, scienceNoiseLevel, templat
             config = subtractImages.AlardLuptonSubtractTask.ConfigClass()
             config.doSubtractBackground = False
             config.forceCompatibility = False
+            config.mode = "convolveScience"
             task = subtractImages.AlardLuptonSubtractTask(config=config)
             output = task.run(template, science, sources)
             self.assertFloatsAlmostEqual(task.metadata["scaleTemplateVarianceFactor"], 1., atol=.05)
@@ -542,6 +543,7 @@ def _run_and_check_images(science, template, sources, statsCtrl,
             """
 
             config = subtractImages.AlardLuptonSubtractTask.ConfigClass()
+            config.mode = "convolveScience"
             config.doSubtractBackground = False
             config.forceCompatibility = False
             config.doDecorrelation = doDecorrelation