erp5_trade: properly use variation API for offset cells

bt5/erp5_trade/SkinTemplateItem/portal_skins/erp5_trade/Inventory_computeOffset.py

@@ -103,30 +103,36 @@ def compareDict(base, compare, path):
 
 for product_relative_url, base_product_content in base_dict.items():
   if not "price" in base_product_content:
-    offset_line = None
-    variation_list = []
-
-    for variation_partial_text, base_variation_content in base_product_content.items():
-      missing_quantity = compareDict(base_dict, compare_dict, [product_relative_url, variation_partial_text])
+    # Cannot create cells upfront because it is first needed to
+    # know the cell range. First iteration prepares all objects
+    # which will be created after.
+    cell_dict = {}
+    for variation_text, base_variation_content in base_product_content.items():
+      missing_quantity = compareDict(base_dict, compare_dict, [product_relative_url, variation_text])
 
       if missing_quantity != 0.0:
-        if offset_line is None:
-          offset_line = context.newContent(
-            portal_type="Inventory Offset Line",
-            resource=product_relative_url,
-          )
-
-        variation = variation_partial_text.split("/", 1)[1]
-        offset_line.newContent(
-          portal_type="Inventory Offset Cell",
-          quantity=missing_quantity,
-          variation=variation,
-          price=base_variation_content["price"],
-        )
-        variation_list.append(variation)
-
-    if offset_line is not None:
+        cell_dict[variation_text] = {
+          "portal_type": "Inventory Offset Cell",
+          "variation": variation_text.split("/", 1)[1],
+          "quantity": missing_quantity,
+          "price": base_variation_content["price"],
+          "base_id": "movement",
+        }
+
+    variation_list = cell_dict.keys()
+    if len(variation_list) > 0:
+      offset_line = context.newContent(
+        portal_type="Inventory Offset Line",
+        resource=product_relative_url,
+      )
       offset_line.setVariationList(variation_list)
+      offset_line.setCellRange(variation_list, base_id="movement")
+
+      for variation_text, cell_kw in cell_dict.items():
+        offset_line.newCell(
+          variation_text,
+          **cell_kw
+        )
   else:
     missing_quantity = compareDict(base_dict, compare_dict, [product_relative_url])