Handle LATEST with never received

Author: ryanmelt

openc3/lib/openc3/models/cvt_model.rb

@@ -411,7 +411,10 @@ def self.determine_latest_packet_for_item(target_name, item_name, cache_timeout:
           latest_packet_name = packet_name
         end
       end
-      raise "Item '#{target_name} LATEST #{item_name}' does not exist for scope: #{scope}" if latest == -1
+      # Return the first packet name if no packets have been received
+      if latest == -1
+        latest_packet_name = packet_names[0]
+      end
       return latest_packet_name
     end
 

openc3/python/openc3/models/cvt_model.py

@@ -442,8 +442,9 @@ def determine_latest_packet_for_item(cls, target_name, item_name, cache_timeout=
             if pkt_hash["PACKET_TIMESECONDS"] and pkt_hash["PACKET_TIMESECONDS"] > latest:
                 latest = pkt_hash["PACKET_TIMESECONDS"]
                 latest_packet_name = packet_name
+        # Return the first packet name if no packets have been received
         if latest == -1:
-            raise RuntimeError(f"Item '{target_name} LATEST {item_name}' does not exist for scope: {scope}")
+            latest_packet_name = packet_names[0]
         return latest_packet_name
 
     @classmethod

openc3/python/test/models/test_cvt_model.py

@@ -22,7 +22,7 @@
 from openc3.models.target_model import TargetModel
 from openc3.packets.packet import Packet
 from openc3.conversions.generic_conversion import GenericConversion
-
+from openc3.utilities.store import Store
 
 class TestCvtModel(unittest.TestCase):
     def setUp(self):
@@ -619,3 +619,13 @@ def test_returns_all_overrides_the_cvt(self):
         CvtModel.normalize("INST", "HEALTH_STATUS", "TEMP2", type="ALL", scope="DEFAULT")
         CvtModel.normalize("INST", "ADCS", "POSX", type="ALL", scope="DEFAULT")
         CvtModel.normalize("SYSTEM", "META", "OPERATOR_NAME", type="ALL", scope="DEFAULT")
+
+    def test_determine_latest_packet_for_item_works_if_not_received(self):
+        model = TargetModel(folder_name="INST", name="INST", scope="DEFAULT")
+        model.create()
+        names = TargetModel.names(scope="DEFAULT")
+        self.assertIn("INST", names)
+        Store.set(f"DEFAULT__INST__item_to_packet_map", json.dumps({"PACKET_ID": ["PACKET1"]}))
+        Store.hset(f"DEFAULT__tlm__INST", "PACKET1", json.dumps({"PACKET_TIMESECONDS": None}))
+        packet_name = CvtModel.determine_latest_packet_for_item("INST", "PACKET_ID", scope="DEFAULT")
+        self.assertNotEqual(packet_name, None)

openc3/spec/models/cvt_model_spec.rb

@@ -344,6 +344,17 @@ def check_temp1
           end)
         expect(packet_name).not_to eq('something')
       end
+
+      it "works_if_not_received" do
+        model = TargetModel.new(folder_name: "INST", name: "INST", scope: "DEFAULT")
+        model.create()
+        names = TargetModel.names(scope:"DEFAULT")
+        expect(names.include?("INST"))
+        Store.set("DEFAULT__INST__item_to_packet_map", JSON.generate({"PACKET_ID" => ["PACKET1"]}))
+        Store.hset("DEFAULT__tlm__INST", "PACKET1", JSON.generate({"PACKET_TIMESECONDS" => nil}))
+        packet_name = CvtModel.determine_latest_packet_for_item("INST", "PACKET_ID", scope:"DEFAULT")
+        expect(packet_name != nil)
+      end
     end
 
     describe "overrides" do