fix(api): Use the latest information when estimating liquid height

api/src/opentrons/protocol_engine/state/geometry.py

@@ -1447,17 +1447,25 @@ def get_meniscus_height(
         well_name: str,
     ) -> float:
         """Returns stored meniscus height in specified well."""
+        last_updated = self._wells.get_last_liquid_update(labware_id, well_name)
+        if last_updated is None:
+            raise errors.LiquidHeightUnknownError(
+                "Must LiquidProbe or LoadLiquid before specifying WellOrigin.MENISCUS."
+            )
+
         well_liquid = self._wells.get_well_liquid_info(
             labware_id=labware_id, well_name=well_name
         )
         if (
             well_liquid.probed_height is not None
             and well_liquid.probed_height.height is not None
+            and well_liquid.probed_height.last_probed == last_updated
         ):
             return well_liquid.probed_height.height
         elif (
             well_liquid.loaded_volume is not None
             and well_liquid.loaded_volume.volume is not None
+            and well_liquid.loaded_volume.last_loaded == last_updated
         ):
             return self.get_well_height_at_volume(
                 labware_id=labware_id,
@@ -1467,15 +1475,17 @@ def get_meniscus_height(
         elif (
             well_liquid.probed_volume is not None
             and well_liquid.probed_volume.volume is not None
+            and well_liquid.probed_volume.last_probed == last_updated
         ):
             return self.get_well_height_at_volume(
                 labware_id=labware_id,
                 well_name=well_name,
                 volume=well_liquid.probed_volume.volume,
             )
         else:
+            # This should not happen if there was an update but who knows
             raise errors.LiquidHeightUnknownError(
-                "Must LiquidProbe or LoadLiquid before specifying WellOrigin.MENISCUS."
+                f"Unable to find liquid height despite an update at {last_updated}."
             )
 
     def get_well_handling_height(

api/src/opentrons/protocol_engine/state/wells.py

@@ -2,6 +2,7 @@
 
 from dataclasses import dataclass
 from typing import Dict, List, Union, Iterator, Optional, Tuple, overload, TypeVar
+from datetime import datetime
 
 from opentrons.protocol_engine.types import (
     ProbedHeightInfo,
@@ -177,6 +178,22 @@ def get_well_liquid_info(self, labware_id: str, well_name: str) -> WellLiquidInf
             probed_volume=probed_volume_info,
         )
 
+    def get_last_liquid_update(
+        self, labware_id: str, well_name: str
+    ) -> Optional[datetime]:
+        """Return the timestamp of the last load or probe done on the well."""
+        info = self.get_well_liquid_info(labware_id, well_name)
+        update_times: List[datetime] = []
+        if info.loaded_volume is not None and info.loaded_volume.volume is not None:
+            update_times.append(info.loaded_volume.last_loaded)
+        if info.probed_height is not None and info.probed_height.height is not None:
+            update_times.append(info.probed_height.last_probed)
+        if info.probed_volume is not None and info.probed_volume.volume is not None:
+            update_times.append(info.probed_volume.last_probed)
+        if len(update_times) > 0:
+            return max(update_times)
+        return None
+
     def get_all(self) -> List[WellInfoSummary]:
         """Get all well liquid info summaries."""
 

api/tests/opentrons/protocol_engine/state/test_geometry_view.py

@@ -62,6 +62,7 @@
     TipGeometry,
     ModuleDefinition,
     ProbedHeightInfo,
+    ProbedVolumeInfo,
     LoadedVolumeInfo,
     WellLiquidInfo,
 )
@@ -1577,10 +1578,14 @@ def test_get_well_position_with_meniscus_offset(
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             probed_volume=None,
-            probed_height=ProbedHeightInfo(height=70.5, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=70.5, last_probed=probe_time),
             loaded_volume=None,
         )
     )
@@ -1639,10 +1644,14 @@ def test_get_well_position_with_volume_offset_raises_error(
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             loaded_volume=None,
-            probed_height=ProbedHeightInfo(height=45.0, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=45.0, last_probed=probe_time),
             probed_volume=None,
         )
     )
@@ -1698,13 +1707,17 @@ def test_get_well_position_with_meniscus_and_literal_volume_offset(
     decoy.when(
         mock_addressable_area_view.get_addressable_area_position(DeckSlotName.SLOT_4.id)
     ).then_return(slot_pos)
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             loaded_volume=None,
-            probed_height=ProbedHeightInfo(height=45.0, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=45.0, last_probed=probe_time),
             probed_volume=None,
         )
     )
@@ -1771,10 +1784,14 @@ def test_get_well_position_with_meniscus_and_float_volume_offset(
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             loaded_volume=None,
-            probed_height=ProbedHeightInfo(height=45.0, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=45.0, last_probed=probe_time),
             probed_volume=None,
         )
     )
@@ -1840,10 +1857,14 @@ def test_get_well_position_raises_validation_error(
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             loaded_volume=None,
-            probed_height=ProbedHeightInfo(height=40.0, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=40.0, last_probed=probe_time),
             probed_volume=None,
         )
     )
@@ -1905,10 +1926,14 @@ def test_get_meniscus_height(
     decoy.when(mock_labware_view.get_well_definition("labware-id", "B2")).then_return(
         well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "B2")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "B2")).then_return(
         WellLiquidInfo(
             loaded_volume=LoadedVolumeInfo(
-                volume=2000.0, last_loaded=datetime.now(), operations_since_load=0
+                volume=2000.0, last_loaded=probe_time, operations_since_load=0
             ),
             probed_height=None,
             probed_volume=None,
@@ -3349,10 +3374,14 @@ def test_validate_dispense_volume_into_well_meniscus(
     decoy.when(mock_labware_view.get_well_geometry("labware-id", "A1")).then_return(
         inner_well_def
     )
+    probe_time = datetime.now()
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        probe_time
+    )
     decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
         WellLiquidInfo(
             loaded_volume=None,
-            probed_height=ProbedHeightInfo(height=40.0, last_probed=datetime.now()),
+            probed_height=ProbedHeightInfo(height=40.0, last_probed=probe_time),
             probed_volume=None,
         )
     )
@@ -3369,6 +3398,129 @@ def test_validate_dispense_volume_into_well_meniscus(
         )
 
 
+def test_get_latest_volume_information(
+    decoy: Decoy,
+    mock_labware_view: LabwareView,
+    mock_well_view: WellView,
+    subject: GeometryView,
+) -> None:
+    """It should raise an InvalidDispenseVolumeError if too much volume is specified."""
+    # Setup
+    labware_def = _load_labware_definition_data()
+    assert labware_def.wells is not None
+    well_def = labware_def.wells["A1"]
+    assert labware_def.innerLabwareGeometry is not None
+    inner_well_def = labware_def.innerLabwareGeometry["welldefinition1111"]
+
+    load_time = datetime.min
+    probe_time = datetime.now()
+
+    decoy.when(mock_labware_view.get_well_definition("labware-id", "A1")).then_return(
+        well_def
+    )
+    decoy.when(mock_labware_view.get_well_geometry("labware-id", "A1")).then_return(
+        inner_well_def
+    )
+    ten_ul_height = subject.get_well_height_at_volume(
+        labware_id="labware-id", well_name="A1", volume=10.0
+    )
+    twenty_ul_height = subject.get_well_height_at_volume(
+        labware_id="labware-id", well_name="A1", volume=20.0
+    )
+
+    # Make sure Get height with no information raises an error
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        None
+    )
+    decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
+        WellLiquidInfo(
+            loaded_volume=None,
+            probed_height=None,
+            probed_volume=None,
+        )
+    )
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        None
+    )
+
+    with pytest.raises(errors.LiquidHeightUnknownError):
+        subject.get_meniscus_height(labware_id="labware-id", well_name="A1")
+    # Make sure get height with a valid load returns the correct height
+    decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
+        WellLiquidInfo(
+            loaded_volume=LoadedVolumeInfo(
+                volume=10.0, last_loaded=load_time, operations_since_load=0
+            ),
+            probed_height=None,
+            probed_volume=None,
+        )
+    )
+
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        load_time
+    )
+    assert (
+        subject.get_meniscus_height(labware_id="labware-id", well_name="A1")
+        == ten_ul_height
+    )
+
+    # Make sure that if there is a probe after a load that we get the correct height
+    decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
+        WellLiquidInfo(
+            loaded_volume=LoadedVolumeInfo(
+                volume=10.0, last_loaded=load_time, operations_since_load=0
+            ),
+            probed_height=ProbedHeightInfo(height=40.0, last_probed=probe_time),
+            probed_volume=None,
+        )
+    )
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        probe_time
+    )
+
+    assert subject.get_meniscus_height(labware_id="labware-id", well_name="A1") == 40.0
+
+    # Simulate a pipetting action and make sure we get the height based on the most current one
+    decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
+        WellLiquidInfo(
+            loaded_volume=LoadedVolumeInfo(
+                volume=10.0, last_loaded=load_time, operations_since_load=1
+            ),
+            probed_height=None,
+            probed_volume=ProbedVolumeInfo(
+                volume=20.0, last_probed=probe_time, operations_since_probe=1
+            ),
+        )
+    )
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        probe_time
+    )
+    assert (
+        subject.get_meniscus_height(labware_id="labware-id", well_name="A1")
+        == twenty_ul_height
+    )
+
+    # Simulate a calling load_liquid after a probe and make sure we get the height based on the load_liquid
+    decoy.when(mock_well_view.get_well_liquid_info("labware-id", "A1")).then_return(
+        WellLiquidInfo(
+            loaded_volume=LoadedVolumeInfo(
+                volume=10.0, last_loaded=datetime.max, operations_since_load=0
+            ),
+            probed_height=ProbedHeightInfo(height=40.0, last_probed=probe_time),
+            probed_volume=ProbedVolumeInfo(
+                volume=20.0, last_probed=probe_time, operations_since_probe=0
+            ),
+        )
+    )
+    decoy.when(mock_well_view.get_last_liquid_update("labware-id", "A1")).then_return(
+        datetime.max
+    )
+    assert (
+        subject.get_meniscus_height(labware_id="labware-id", well_name="A1")
+        == ten_ul_height
+    )
+
+
 @pytest.mark.parametrize(
     [
         "labware_id",