Another couple of fixups

1. Improved error message when the butler understood the dataId but
couldn't read the file
2. Explained allowRotate=False and made it's use slightly more accurate

python/lsst/afw/cameraGeom/utils.py

@@ -28,11 +28,13 @@
 import warnings
 
 import lsst.geom
+from lsst.afw.fits import FitsError
 import lsst.afw.geom as afwGeom
 import lsst.afw.image as afwImage
 import lsst.afw.math as afwMath
 import lsst.daf.base as dafBase
 import lsst.log
+import lsst.pex.exceptions as pexExceptions
 
 from .rotateBBoxBy90 import rotateBBoxBy90
 from .assembleImage import assembleAmplifierImage, assembleAmplifierRawImage
@@ -459,22 +461,28 @@ def getCcdImage(self, ccd, imageFactory=afwImage.ImageF, binSize=1):
 
         im = None
         if self.butler is not None:
-            im = None
+            err = None
             for dataId in [dict(detector=ccd.getId()), dict(ccd=ccd.getId()), dict(ccd=ccd.getName())]:
                 try:
                     im = self.butler.get(self.type, dataId, **self.kwargs)
-                    ccd = im.getDetector()  # possibly modified by assembleCcdTask
+                except FitsError as e:  # no point trying another dataId
+                    err = IOError(e.args[0].split('\n')[0]) # It's a very chatty error
                     break
-                except Exception as e:
-                    err = e
+                except Exception as e:  # try a different dataId
+                    if err is None:
+                        err = e
                     continue
+                else:
+                    ccd = im.getDetector()  # possibly modified by assembleCcdTask
+                    break
 
             if im:
                 im = im.getMaskedImage().getImage()
             else:
                 if self.verbose:
-                    print("Reading %s: %s" % (ccd.getId(), err))
-                    log.warn("Reading %s: %s" % (ccd.getId(), err))
+                    print("Reading %s: %s" % (ccd.getId(), err))  # lost by jupyterLab
+
+                log.warn("Reading %s: %s", ccd.getId(), err)
 
         if im is None:
             return self._prepareImage(ccd, imageFactory(*bbox.getDimensions()), binSize), ccd
@@ -485,15 +493,18 @@ def getCcdImage(self, ccd, imageFactory=afwImage.ImageF, binSize=1):
             if False and self.callback is None:   # we need to trim the raw image
                 self.callback = rawCallback
 
+        allowRotate = True
         if self.callback:
             try:
                 im = self.callback(im, ccd, imageSource=self)
             except Exception as e:
                 if self.verbose:
                     log.error("callback failed: %s" % e)
                 im = imageFactory(*bbox.getDimensions())
+            else:
+                allowRotate = False     # the callback was responsible for any rotations
 
-        return self._prepareImage(ccd, im, binSize, allowRotate=False), ccd
+        return self._prepareImage(ccd, im, binSize, allowRotate=allowRotate), ccd
 
 
 def rawCallback(im, ccd=None, imageSource=None,