From ff33cc43bd66a1931370e603162aed9ebf13e06b Mon Sep 17 00:00:00 2001
From: Oliver <oliver.henry.walters@gmail.com>
Date: Mon, 21 Jun 2021 17:28:41 +1000
Subject: [PATCH 1/2] Create initial migration file

---
 .../migrations/0064_auto_20210621_1724.py     | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 InvenTree/stock/migrations/0064_auto_20210621_1724.py

diff --git a/InvenTree/stock/migrations/0064_auto_20210621_1724.py b/InvenTree/stock/migrations/0064_auto_20210621_1724.py
new file mode 100644
index 0000000000..bc40a7523b
--- /dev/null
+++ b/InvenTree/stock/migrations/0064_auto_20210621_1724.py
@@ -0,0 +1,41 @@
+# Generated by Django 3.2.4 on 2021-06-21 07:24
+
+from django.db import migrations
+
+
+def extract_purchase_price(apps, schema_editor):
+    """
+    Find instances of StockItem which do *not* have a purchase price set,
+    but which point to a PurchaseOrder where there *is* a purchase price set.
+
+    Then, assign *that* purchase price to original StockItem.
+
+    This is to address an issue where older versions of InvenTree
+    did not correctly copy purchase price information cross to the StockItem objects.
+
+    Current InvenTree version (as of 2021-06-21) copy this information across correctly,
+    so this one-time data migration should suffice.
+    """
+
+    # Required database models
+    StockItem = apps.get_model('stock', 'stockitem')
+    PurchaseOrder = apps.get_model('order', 'purchaseorder')
+    Part = apps.get_model('part', 'part')
+
+
+def reverse_operation(apps, schema_editor):
+    """
+    DO NOTHING!
+    """
+    pass
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('stock', '0063_auto_20210511_2343'),
+    ]
+
+    operations = [
+        migrations.RunPython(extract_purchase_price, reverse_code=reverse_operation)
+    ]

From 02540edd589c51cdd20bb330174fb45cc58d7cc9 Mon Sep 17 00:00:00 2001
From: Oliver <oliver.henry.walters@gmail.com>
Date: Mon, 21 Jun 2021 20:30:15 +1000
Subject: [PATCH 2/2] Copy purchase price information across in the data
 migration

---
 .../migrations/0064_auto_20210621_1724.py     | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/InvenTree/stock/migrations/0064_auto_20210621_1724.py b/InvenTree/stock/migrations/0064_auto_20210621_1724.py
index bc40a7523b..71314f366c 100644
--- a/InvenTree/stock/migrations/0064_auto_20210621_1724.py
+++ b/InvenTree/stock/migrations/0064_auto_20210621_1724.py
@@ -20,8 +20,43 @@ def extract_purchase_price(apps, schema_editor):
     # Required database models
     StockItem = apps.get_model('stock', 'stockitem')
     PurchaseOrder = apps.get_model('order', 'purchaseorder')
+    PurchaseOrderLineItem = apps.get_model('order', 'purchaseorderlineitem')
     Part = apps.get_model('part', 'part')
 
+    # Find all the StockItem objects without a purchase_price which point to a PurchaseOrder
+    items = StockItem.objects.filter(purchase_price=None).exclude(purchase_order=None)
+
+    print(f"Found {items.count()} stock items with missing purchase price information")
+
+    update_count = 0
+
+    for item in items:
+
+        part_id = item.part
+
+        po = item.purchase_order
+
+        # Look for a matching PurchaseOrderLineItem (with a price)
+        lines = PurchaseOrderLineItem.objects.filter(part__part=part_id, order=po)
+
+        if lines.exists():
+
+            for line in lines:
+                if line.purchase_price is not None:
+
+                    # Copy pricing information across
+                    item.purchase_price = line.purchase_price
+                    item.purchases_price_currency = line.purchase_price_currency
+
+                    print(f"- Updating supplier price for {item.part.name} - {item.purchase_price} {item.purchase_price_currency}")
+
+                    update_count += 1
+
+                    item.save()
+
+                    break
+
+    print(f"Updated pricing for {update_count} stock items")
 
 def reverse_operation(apps, schema_editor):
     """