fix(resources): align a lidded plate on a plate adapter by its wells

CHANGELOG.md

@@ -43,6 +43,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - `HamiltonTCPClient.setup()` now resets all per-session state (client id, sequence numbers, instrument addresses, object registry) rather than carrying it into the new session, and refuses to run on an already-connected client instead of leaking the socket (#1195).
 - `HamiltonTCPClient` no longer recurses without bound when a device fails the introspection queries that error enrichment itself issues. Enrichment is now non-re-entrant and falls back to the static HC_RESULT tables, so a degraded instrument yields a terse error instead of a `RecursionError` (#1195).
 - `HamiltonTCPClient` no longer fails every command after the device sends a HARP control frame. MLPrep firmware sends one (options, no HOI body) shortly after registration; it was parsed as a command response and killed the reader. Frames with no routable message are skipped, as are unparsable frames, which is safe because frames are length-prefixed and consumed whole (#1195).
+- `PlateAdapter.compute_plate_location` reads the grid from the plate's wells alone, so a plate carrying a lid can be assigned or moved onto a plate adapter instead of raising `ValueError: well spacing has to be uniform`.
 
 ### Changed
 

pylabrobot/resources/plate_adapter.py

@@ -124,9 +124,11 @@ def compute_plate_location(self, resource: Plate) -> Coordinate:
     align the `Plate` well-grid with the adapter's hole grid."""
 
     # Calculate Plate information (which is not directly accessible from the Plate class)
+    # Wells only: a plate's lid is among its children too.
     # Child locations are never None, so we can safely ignore the type error
-    x_locations = sorted(set(well_n.location.x for well_n in resource.children))  # type: ignore
-    y_locations = sorted(set(well_n.location.y for well_n in resource.children))  # type: ignore
+    wells = resource.get_wells()
+    x_locations = sorted(set(well_n.location.x for well_n in wells))  # type: ignore
+    y_locations = sorted(set(well_n.location.y for well_n in wells))  # type: ignore
 
     def calculate_well_spacing(float_list: List[float]):
       """Calculate the difference between every x and x+1 element in the list of floats."""
@@ -142,8 +144,8 @@ def calculate_well_spacing(float_list: List[float]):
     plate_dx, plate_dy = float(x_locations[0]), float(y_locations[0])
     plate_item_dx = abs(calculate_well_spacing(x_locations))
     plate_item_dy = abs(calculate_well_spacing(y_locations))
-    well_size_x = resource.children[0].get_absolute_size_x()
-    well_size_y = resource.children[0].get_absolute_size_y()
+    well_size_x = wells[0].get_absolute_size_x()
+    well_size_y = wells[0].get_absolute_size_y()
     # true_dz = resource.get_size_z() - resource.children[0].get_size_z()
 
     # Well-grid to hole-grid compatibility check

pylabrobot/resources/plate_adapter_tests.py

@@ -2,6 +2,7 @@
 
 from pylabrobot.resources import (
   Coordinate,
+  Lid,
   Plate,
   PlateAdapter,
   Well,
@@ -94,3 +95,33 @@ def test_rectangular_hole_centers_each_axis_on_its_own_size(self):
     well_center = plate.get_well("H1").get_location_wrt(adapter, x="c", y="c", z="b")
     self.assertAlmostEqual(well_center.x, adapter.dx + adapter.adapter_hole_size_x / 2)
     self.assertAlmostEqual(well_center.y, adapter.dy + adapter.adapter_hole_size_y / 2)
+
+  def test_lid_is_not_taken_for_a_well(self):
+    """A plate is placed on the adapter where it goes without its lid."""
+
+    plate = Plate(
+      name="plate",
+      size_x=127.76,
+      size_y=85.48,
+      size_z=14.0,
+      ordered_items=create_ordered_items_2d(
+        Well,
+        num_items_x=12,
+        num_items_y=8,
+        dx=9.5,
+        dy=6.5,
+        dz=1.0,
+        item_dx=9.0,
+        item_dy=9.0,
+        size_x=6.0,
+        size_y=6.0,
+        size_z=10.0,
+      ),
+    )
+    without_lid = _adapter.compute_plate_location(plate)
+
+    plate.assign_child_resource(
+      Lid(name="lid", size_x=127.76, size_y=85.48, size_z=8.0, nesting_z_height=6.0)
+    )
+
+    self.assertEqual(_adapter.compute_plate_location(plate), without_lid)