[FIX] stock_picking_batch_custom: prevent product_id null error on summary lines

- Use regular dict instead of defaultdict to avoid empty entries
- Make summary_line_ids readonly=True to prevent UI from inserting empty lines
- Add SQL constraint CHECK(product_id IS NOT NULL) as safeguard
- Use boolean_toggle widget for is_collected field
- Fix tests to use TransactionCase and invalidate_recordset
- Add test for empty batch + add pickings + confirm flow

stock_picking_batch_custom/tests/__init__.py

@@ -0,0 +1 @@
+from . import test_batch_summary  # noqa: F401

stock_picking_batch_custom/tests/test_batch_summary.py

@@ -1,10 +1,12 @@
 # Copyright 2026 Criptomart
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
 
-from odoo.tests.common import SavepointCase
+from odoo.tests import tagged
+from odoo.tests.common import TransactionCase
 
 
-class TestBatchSummary(SavepointCase):
+@tagged("-at_install", "post_install")
+class TestBatchSummary(TransactionCase):
     @classmethod
     def setUpClass(cls):
         super().setUpClass()
@@ -62,7 +64,7 @@ class TestBatchSummary(SavepointCase):
                     "move_id": move.id,
                     "picking_id": picking.id,
                     "product_id": self.product.id,
-                    "product_uom_id": uom.id,
+                    "product_uom_id": self.product.uom_id.id,
                     "location_id": self.location_src.id,
                     "location_dest_id": self.location_dest.id,
                     "quantity": qty_done,
@@ -71,9 +73,45 @@ class TestBatchSummary(SavepointCase):
         return move
 
     def _recompute_batch(self):
-        self.batch.invalidate_cache()
+        self.batch.invalidate_recordset()
         self.batch._compute_summary_line_ids()
 
+    def _create_batch_with_pickings(self):
+        batch = self.env["stock.picking.batch"].create(
+            {"name": "Batch Flow", "picking_type_id": self.picking_type.id}
+        )
+        picking = self.env["stock.picking"].create(
+            {
+                "picking_type_id": self.picking_type.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+        move = self.env["stock.move"].create(
+            {
+                "name": self.product.name,
+                "product_id": self.product.id,
+                "product_uom_qty": 2.0,
+                "product_uom": self.uom_unit.id,
+                "picking_id": picking.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+        self.env["stock.move.line"].create(
+            {
+                "move_id": move.id,
+                "picking_id": picking.id,
+                "product_id": self.product.id,
+                "product_uom_id": self.uom_unit.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+                "quantity": 2.0,
+            }
+        )
+        picking.batch_id = batch.id
+        return batch
+
     # Tests
     def test_totals_and_pending_with_conversion(self):
         """Totals aggregate per product with UoM conversion and pending."""
@@ -125,3 +163,127 @@ class TestBatchSummary(SavepointCase):
         self._recompute_batch()
 
         self.assertFalse(self.batch.summary_line_ids)
+
+    def test_no_required_product_error_on_confirm(self):
+        """Confirming batch with pickings must not create summary lines without product."""
+
+        batch = self._create_batch_with_pickings()
+
+        # Trigger compute via confirm flow
+        batch.action_confirm()
+
+        self.assertTrue(batch.summary_line_ids)
+        self.assertFalse(
+            batch.summary_line_ids.filtered(lambda line: not line.product_id)
+        )
+
+    def test_empty_batch_add_pickings_then_confirm(self):
+        """Create empty draft batch, add multiple pickings, then confirm."""
+
+        # 1. Create empty batch in draft state
+        batch = self.env["stock.picking.batch"].create(
+            {"name": "Batch Empty Start", "picking_type_id": self.picking_type.id}
+        )
+        self.assertEqual(batch.state, "draft")
+        self.assertFalse(batch.picking_ids)
+        self.assertFalse(batch.summary_line_ids)
+
+        # 2. Create pickings with moves (without batch assignment)
+        product2 = self.env["product.product"].create(
+            {
+                "name": "Test Product 2",
+                "uom_id": self.uom_unit.id,
+                "uom_po_id": self.uom_unit.id,
+            }
+        )
+
+        picking_a = self.env["stock.picking"].create(
+            {
+                "picking_type_id": self.picking_type.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+        self.env["stock.move"].create(
+            {
+                "name": self.product.name,
+                "product_id": self.product.id,
+                "product_uom_qty": 5.0,
+                "product_uom": self.uom_unit.id,
+                "picking_id": picking_a.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+
+        picking_b = self.env["stock.picking"].create(
+            {
+                "picking_type_id": self.picking_type.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+        self.env["stock.move"].create(
+            {
+                "name": product2.name,
+                "product_id": product2.id,
+                "product_uom_qty": 10.0,
+                "product_uom": self.uom_unit.id,
+                "picking_id": picking_b.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+
+        picking_c = self.env["stock.picking"].create(
+            {
+                "picking_type_id": self.picking_type.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+        self.env["stock.move"].create(
+            {
+                "name": self.product.name,
+                "product_id": self.product.id,
+                "product_uom_qty": 3.0,
+                "product_uom": self.uom_unit.id,
+                "picking_id": picking_c.id,
+                "location_id": self.location_src.id,
+                "location_dest_id": self.location_dest.id,
+            }
+        )
+
+        # 3. Add pickings to the batch
+        picking_a.batch_id = batch
+        picking_b.batch_id = batch
+        picking_c.batch_id = batch
+
+        self.assertEqual(len(batch.picking_ids), 3)
+
+        # 4. Confirm the batch — this should not raise product_id required error
+        batch.action_confirm()
+
+        self.assertEqual(batch.state, "in_progress")
+
+        # 5. Verify summary lines are correct
+        self.assertTrue(batch.summary_line_ids)
+        self.assertFalse(
+            batch.summary_line_ids.filtered(lambda line: not line.product_id)
+        )
+
+        # Two products expected
+        products_in_summary = batch.summary_line_ids.mapped("product_id")
+        self.assertIn(self.product, products_in_summary)
+        self.assertIn(product2, products_in_summary)
+
+        # Check aggregated quantities
+        line_product1 = batch.summary_line_ids.filtered(
+            lambda line: line.product_id == self.product
+        )
+        self.assertAlmostEqual(line_product1.qty_demanded, 8.0)  # 5 + 3
+
+        line_product2 = batch.summary_line_ids.filtered(
+            lambda line: line.product_id == product2
+        )
+        self.assertAlmostEqual(line_product2.qty_demanded, 10.0)