DM-53177 : Allow 8-char object IDs with backwards compatibility

python/lsst/pipe/tasks/associationUtils.py

@@ -195,7 +195,7 @@ def query_disc(nside, ra, dec, max_rad, min_rad=0):
     return pixels
 
 
-def obj_id_to_ss_object_id(objID, flags=0):
+def obj_id_to_ss_object_id(objID):
     """Convert from Minor Planet Center packed provisional object ID to
     Rubin ssObjectID.
 
@@ -204,10 +204,6 @@ def obj_id_to_ss_object_id(objID, flags=0):
     objID : `str`
         Minor Planet Center packed provisional designation for a small solar
         system object. Must be fewer than eight characters.
-    flags : `int`, optional
-        Eight free bits to enable future decoupling between Minor Planet Center
-        and Rubin. Zero by default, should not be changed unless we need to
-        move away from a 1:1 mapping with the MPC. Must be within [0, 255].
 
     Returns
     -------
@@ -217,20 +213,18 @@ def obj_id_to_ss_object_id(objID, flags=0):
     Raises
     ------
     ValueError
-        Raised if either objID is longer than 7 characters or flags is greater
-        than 255 or less than 0.
+        Raised if either objID is shorter than 7 or longer than 8 characters or contains
+        illegal objID characters
     """
-    if len(objID) > 7:
-        raise ValueError(f'objID longer than 7 characters: "{objID}"')
+    if len(objID) > 8:
+        raise ValueError(f'objID longer than 8 characters: "{objID}"')
     if len(objID) < 7:
         raise ValueError(f'objID shorter than 7 characters: "{objID}"')
-    if flags < 0 or flags > 255:
-        raise ValueError(f'Flags ({flags}) outside [0, 255].')
     if any([ord(c) > 255 for c in objID]):
         raise ValueError(f'{[c for c in objID if ord(c) > 255]} not legal objID characters (ascii [1, 255])')
 
-    ssObjectID = flags
-    for character in objID:
+    ssObjectID = ord(objID[0])
+    for character in objID[1:]:
         ssObjectID <<= 8
         ssObjectID += ord(character)
     return ssObjectID
@@ -250,14 +244,12 @@ def ss_object_id_to_obj_id(ssObjectID):
     objID : `str`
         Minor Planet Center packed provisional designation.
 
-    flags : `int`
-        Rubin flags (not yet defined, but usable in case we decouple from MPC).
-
     Raises
     ------
     """
     if ssObjectID < 0 or ssObjectID >= (1 << 64):
         raise ValueError(f'ssObjectID ({ssObjectID}) outside [0, 2^64 - 1].')
 
-    objID = ''.join([chr((ssObjectID >> (8 * i)) % 256) for i in reversed(range(0, 7))])
-    return objID, ssObjectID >> (8 * 7) % 256
+    objID = ''.join([chr((ssObjectID >> (8 * i)) % 256) for i in reversed(range(0, 8))])
+    objID = objID.replace('\x00', '')
+    return objID

tests/test_associationUtils.py

@@ -60,44 +60,24 @@ def test_conversions_between_obj_id_and_ss_object_id(self):
         """
         allowed_strings = ['J95X00A', 'J95X01L', 'J95F13B', 'J98SA8Q', 'J98SC7V', 'J98SG2S'] \
             + ['K99AJ3Z', 'K08Aa0A', 'K07Tf8A', 'PLS2040', 'T1S3138', 'T2S1010', 'T3S4101'] \
-            + ['       ', '\x00\x00\x00\x00\x00\x00\x00']
-        allowed_flags = [i for i in range(0, 256)]
-        allowed_ssObjectIDs = [0, 1 << 64 - 1] + [1 << n for n in range(64)]
+            + ['       ', 'PJ48Q010', 'AAAAAAAA']
         for allowed_string in allowed_strings:
-            for allowed_flag in allowed_flags:
-                returned_string, returned_flag = ss_object_id_to_obj_id(
-                    obj_id_to_ss_object_id(allowed_string, allowed_flag))
-                self.assertEqual((allowed_string, allowed_flag), (returned_string, returned_flag))
-        for allowed_ssObjectID in allowed_ssObjectIDs:
-            returned_ssObjectID = obj_id_to_ss_object_id(*ss_object_id_to_obj_id(allowed_ssObjectID))
-            self.assertEqual(allowed_ssObjectID, returned_ssObjectID)
+            returned_string = ss_object_id_to_obj_id(obj_id_to_ss_object_id(allowed_string))
+            self.assertEqual(allowed_string, returned_string)
 
     def test_invalid_conversions_between_obj_id_and_ss_object_id(self):
         """Convert between ssObjectIDs and MPC packed designations
         """
-        allowed_strings = ['J95X00A', 'J95X01L', 'J95F13B', 'J98SA8Q', 'J98SC7V', 'J98SG2S'] \
-            + ['K99AJ3Z', 'K08Aa0A', 'K07Tf8A', 'PLS2040', 'T1S3138', 'T2S1010', 'T3S4101']
-        allowed_flags = [i for i in range(0, 256)]
-        disallowed_flags = [-999999999, -512, -256, -255, -1, 256, 512, 99999999]
         disallowed_strings = [''] + [ch for ch in 'ABCDEFGHIJKMNOPQRSTUVWXYZ0123456789 -'] \
             + ['A' * i for i in range(2, 7)] + ['Z' * i for i in range(2, 7)] \
-            + ['Ā', '🔭', 'A' * 8, ' ' * 8, 'A' * 128]
+            + ['Ā', '🔭', 'A' * 9, ' ' * 9, 'A' * 128]
         disallowed_ssObjectIDs = [-1, 1 << 64, 1 << 64 + 1, 2 << 65]
-        for allowed_string in allowed_strings:
-            for disallowed_flag in disallowed_flags:
-                with self.assertRaises(ValueError):
-                    obj_id_to_ss_object_id(allowed_string, disallowed_flag)
-        for disallowed_string in disallowed_strings:
-            for allowed_flag in allowed_flags:
-                with self.assertRaises(ValueError):
-                    obj_id_to_ss_object_id(disallowed_string, allowed_flag)
-        for disallowed_string in disallowed_strings:
-            for disallowed_flag in disallowed_flags:
-                with self.assertRaises(ValueError):
-                    obj_id_to_ss_object_id(disallowed_string, disallowed_flag)
         for disallowed_ssObjectID in disallowed_ssObjectIDs:
             with self.assertRaises(ValueError):
                 ss_object_id_to_obj_id(disallowed_ssObjectID)
+        for disallowed_string in disallowed_strings:
+            with self.assertRaises(ValueError):
+                obj_id_to_ss_object_id(disallowed_string)
 
 
 class MemoryTestCase(lsst.utils.tests.MemoryTestCase):