NO TICKET: Handle NaN MP height and NULL history entries in legacy data transfers and property reads

db/thing.py

@@ -495,10 +495,15 @@ def measuring_point_height(self) -> int | None:
         Since measuring_point_history is eagerly loaded, this should not introduce N+1 query issues.
         """
         if self.thing_type == "water well":
+            if not self.measuring_points:
+                return None
             sorted_measuring_point_history = sorted(
                 self.measuring_points, key=lambda x: x.start_date, reverse=True
             )
-            return sorted_measuring_point_history[0].measuring_point_height
+            for record in sorted_measuring_point_history:
+                if record.measuring_point_height is not None:
+                    return record.measuring_point_height
+            return None
         else:
             return None
 
@@ -511,10 +516,15 @@ def measuring_point_description(self) -> str | None:
         Since measuring_point_history is eagerly loaded, this should not introduce N+1 query issues.
         """
         if self.thing_type == "water well":
+            if not self.measuring_points:
+                return None
             sorted_measuring_point_history = sorted(
                 self.measuring_points, key=lambda x: x.start_date, reverse=True
             )
-            return sorted_measuring_point_history[0].measuring_point_description
+            for record in sorted_measuring_point_history:
+                if record.measuring_point_description is not None:
+                    return record.measuring_point_description
+            return None
         else:
             return None
 

tests/test_thing.py

@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 # ===============================================================================
-from datetime import timezone
+from datetime import date, timezone
 
 import pytest
 
@@ -25,7 +25,8 @@
     viewer_function,
     amp_viewer_function,
 )
-from db import Thing, WellScreen, ThingIdLink
+from db import MeasuringPointHistory, Thing, ThingIdLink, WellScreen
+from db.engine import session_ctx
 from main import app
 from schemas import DT_FMT
 from schemas.location import LocationResponse
@@ -85,6 +86,46 @@ def test_update_well_allows_nma_formation_zone():
     assert payload.nma_formation_zone == "FZ-001"
 
 
+def test_measuring_point_properties_skip_null_history():
+    with session_ctx() as session:
+        well = Thing(
+            name="Null MP Height Well",
+            thing_type="water well",
+            release_status="draft",
+        )
+        session.add(well)
+        session.commit()
+        session.refresh(well)
+
+        old_history = MeasuringPointHistory(
+            thing_id=well.id,
+            measuring_point_height=2.5,
+            measuring_point_description="old mp",
+            start_date=date(2020, 1, 1),
+            end_date=None,
+            release_status="draft",
+        )
+        new_history = MeasuringPointHistory(
+            thing_id=well.id,
+            measuring_point_height=None,
+            measuring_point_description=None,
+            start_date=date(2021, 1, 1),
+            end_date=None,
+            release_status="draft",
+        )
+        session.add_all([old_history, new_history])
+        session.commit()
+        session.refresh(well)
+
+        assert well.measuring_point_height == 2.5
+        assert well.measuring_point_description == "old mp"
+
+        session.delete(new_history)
+        session.delete(old_history)
+        session.delete(well)
+        session.commit()
+
+
 # this is not a valid test because measuring_point_height is not related to hole_depth
 # def test_validate_mp_height_hole_depth():
 #     with pytest.raises(

transfers/well_transfer.py

@@ -569,16 +569,9 @@ def _build_well_payload(self, row) -> CreateWell | None:
 
             mpheight = row.MPHeight
             mpheight_description = row.MeasuringPoint
-            if mpheight is None:
-                mphs = self._measuring_point_estimator.estimate_measuring_point_height(
-                    row
-                )
-                if mphs:
-                    try:
-                        mpheight = mphs[0][0]
-                        mpheight_description = mphs[1][0]
-                    except IndexError:
-                        pass
+            if mpheight is None or isna(mpheight):
+                # Treat missing/NaN MPHeight as unknown during migration.
+                mpheight = None
 
             completion_date, completion_date_parse_failed = _normalize_completion_date(
                 row.CompletionDate
@@ -736,22 +729,9 @@ def _add_notes_and_provenance(
                 )
 
     def _add_histories(self, session: Session, row, well: Thing) -> None:
-        mphs = self._measuring_point_estimator.estimate_measuring_point_height(row)
-        added_measuring_point = False
-        for mph, mph_desc, start_date, end_date in zip(*mphs):
-            session.add(
-                MeasuringPointHistory(
-                    thing_id=well.id,
-                    measuring_point_height=mph,
-                    measuring_point_description=mph_desc,
-                    start_date=start_date,
-                    end_date=end_date,
-                )
-            )
-            added_measuring_point = True
-
-        # Preserve transfer intent even when no MP height can be measured/estimated.
-        if not added_measuring_point:
+        raw_mpheight = getattr(row, "MPHeight", None)
+        if raw_mpheight is None or isna(raw_mpheight):
+            # No estimator for NaN/missing MPHeight; persist NULL history row.
             raw_desc = getattr(row, "MeasuringPoint", None)
             mp_desc = None if isna(raw_desc) else raw_desc
             session.add(
@@ -763,6 +743,34 @@ def _add_histories(self, session: Session, row, well: Thing) -> None:
                     end_date=None,
                 )
             )
+        else:
+            mphs = self._measuring_point_estimator.estimate_measuring_point_height(row)
+            added_measuring_point = False
+            for mph, mph_desc, start_date, end_date in zip(*mphs):
+                session.add(
+                    MeasuringPointHistory(
+                        thing_id=well.id,
+                        measuring_point_height=mph,
+                        measuring_point_description=mph_desc,
+                        start_date=start_date,
+                        end_date=end_date,
+                    )
+                )
+                added_measuring_point = True
+
+            # Preserve transfer intent even when no MP height can be measured/estimated.
+            if not added_measuring_point:
+                raw_desc = getattr(row, "MeasuringPoint", None)
+                mp_desc = None if isna(raw_desc) else raw_desc
+                session.add(
+                    MeasuringPointHistory(
+                        thing_id=well.id,
+                        measuring_point_height=None,
+                        measuring_point_description=mp_desc,
+                        start_date=datetime.now(tz=UTC).date(),
+                        end_date=None,
+                    )
+                )
 
         target_id = well.id
         target_table = "thing"