Part units (#4854)

* Add validation to part units field

* Add "pack_units" field to the SupplierPart model

* Migrate old units to new units, and remove old field

* Table fix

* Fixture fix

* Update migration

* Improve "hook" for loading custom unit database

* Display part units column in part table

- Also allow ordering by part units
- Allow filtering to show parts which have defined units

* Adds data migration for converting units to valid values

* Add "pack_units_native" field to company.SupplierPart model

* Clean pack units when saving a SupplierPart

- Convert to native part units
- Handle empty units value
- Add unit tests

* Add background function to rebuild supplier parts when a part is saved

- Required to ensure that the "pack_size_native" is up to date

* Template updates

* Sort by native units first

* Bump API version

* Rename "pack_units" to "pack_quantity"

* Update migration file

- Allow reverse migration

* Fix for currency migration

- Handle case where no currencies are provided
- Handle case where base currency is not in provided options

* Adds unit test for data migration

* Add unit test for part.units data migration

- Check that units fields are updated correctly

* Add some extra "default units"

- each / piece
- dozen / hundred / thousand
- Add unit testing also

* Update references to "pack_size"

- Replace with "pack_quantity" or "pack_quantity_native" as appropriate

* Improvements based on unit testing

* catch error

* Docs updates

* Fixes for pricing tests

* Update unit tests for part migrations · 1b6b6d9d

* Bug fix for conversion code

* javascript updates

* JS formatting fix

InvenTree/InvenTree/api_version.py

@@ -2,11 +2,16 @@
 
 
 # InvenTree API version
-INVENTREE_API_VERSION = 116
+INVENTREE_API_VERSION = 117
 
 """
 Increment this API version number whenever there is a significant change to the API that any clients need to know about
 
+v117 -> 2023-05-22 : https://github.com/inventree/InvenTree/pull/4854
+    - Part.units model now supports physical units (e.g. "kg", "m", "mm", etc)
+    - Replaces SupplierPart "pack_size" field with "pack_quantity"
+    - New field supports physical units, and allows for conversion between compatible units
+
 v116 -> 2023-05-18 : https://github.com/inventree/InvenTree/pull/4823
     - Updates to part parameter implementation, to use physical units
 

InvenTree/InvenTree/apps.py

@@ -11,6 +11,7 @@ from django.core.exceptions import AppRegistryNotReady
 from django.db import transaction
 from django.db.utils import IntegrityError
 
+import InvenTree.conversion
 import InvenTree.tasks
 from InvenTree.config import get_setting
 from InvenTree.ready import canAppAccessDatabase, isInTestMode
@@ -46,6 +47,9 @@ class InvenTreeConfig(AppConfig):
 
         self.collect_notification_methods()
 
+        # Ensure the unit registry is loaded
+        InvenTree.conversion.reload_unit_registry()
+
         if canAppAccessDatabase() or settings.TESTING_ENV:
             self.add_user_on_startup()
 

InvenTree/InvenTree/conversion.py

@@ -15,13 +15,31 @@ def get_unit_registry():
 
     # Cache the unit registry for speedier access
     if _unit_registry is None:
-        _unit_registry = pint.UnitRegistry()
+        reload_unit_registry()
-
-    # TODO: Allow for custom units to be defined in the database
 
     return _unit_registry
 
 
+def reload_unit_registry():
+    """Reload the unit registry from the database.
+
+    This function is called at startup, and whenever the database is updated.
+    """
+
+    global _unit_registry
+
+    _unit_registry = pint.UnitRegistry()
+
+    # Define some "standard" additional units
+    _unit_registry.define('piece = 1')
+    _unit_registry.define('each = 1 = ea')
+    _unit_registry.define('dozen = 12 = dz')
+    _unit_registry.define('hundred = 100')
+    _unit_registry.define('thousand = 1000')
+
+    # TODO: Allow for custom units to be defined in the database
+
+
 def convert_physical_value(value: str, unit: str = None):
     """Validate that the provided value is a valid physical quantity.
 
@@ -30,7 +48,7 @@ def convert_physical_value(value: str, unit: str = None):
         unit: Optional unit to convert to, and validate against
 
     Raises:
-        ValidationError: If the value is invalid
+        ValidationError: If the value is invalid or cannot be converted to the specified unit
 
     Returns:
         The converted quantity, in the specified units
@@ -62,11 +80,9 @@ def convert_physical_value(value: str, unit: str = None):
         # At this point we *should* have a valid pint value
         # To double check, look at the maginitude
         float(val.magnitude)
-    except ValueError:
+    except (TypeError, ValueError):
         error = _('Provided value is not a valid number')
-    except pint.errors.UndefinedUnitError:
+    except (pint.errors.UndefinedUnitError, pint.errors.DefinitionSyntaxError):
-        error = _('Provided value has an invalid unit')
-    except pint.errors.DefinitionSyntaxError:
         error = _('Provided value has an invalid unit')
     except pint.errors.DimensionalityError:
         error = _('Provided value could not be converted to the specified unit')

InvenTree/InvenTree/tests.py

@@ -18,6 +18,7 @@ from djmoney.contrib.exchange.exceptions import MissingRate
 from djmoney.contrib.exchange.models import Rate, convert_money
 from djmoney.money import Money
 
+import InvenTree.conversion
 import InvenTree.format
 import InvenTree.helpers
 import InvenTree.tasks
@@ -33,6 +34,28 @@ from .tasks import offload_task
 from .validators import validate_overage
 
 
+class ConversionTest(TestCase):
+    """Tests for conversion of physical units"""
+
+    def test_dimensionless_units(self):
+        """Tests for 'dimensonless' unit quantities"""
+
+        # Test some dimensionless units
+        tests = {
+            'ea': 1,
+            'each': 1,
+            '3 piece': 3,
+            '5 dozen': 60,
+            '3 hundred': 300,
+            '2 thousand': 2000,
+            '12 pieces': 12,
+        }
+
+        for val, expected in tests.items():
+            q = InvenTree.conversion.convert_physical_value(val).to_base_units()
+            self.assertEqual(q.magnitude, expected)
+
+
 class ValidatorTest(TestCase):
     """Simple tests for custom field validators."""
 

InvenTree/company/api.py

@@ -390,7 +390,7 @@ class SupplierPartList(ListCreateDestroyAPIView):
         'manufacturer',
         'MPN',
         'packaging',
-        'pack_size',
+        'pack_quantity',
         'in_stock',
         'updated',
     ]
@@ -400,6 +400,7 @@ class SupplierPartList(ListCreateDestroyAPIView):
         'supplier': 'supplier__name',
         'manufacturer': 'manufacturer_part__manufacturer__name',
         'MPN': 'manufacturer_part__MPN',
+        'pack_quantity': ['pack_quantity_native', 'pack_quantity'],
     }
 
     search_fields = [

InvenTree/company/fixtures/supplier_part.yaml

@@ -66,4 +66,5 @@
     part: 4
     supplier: 2
     SKU: 'R_4K7_0603.100PCK'
-    pack_size: 100
+    pack_quantity: '100'
+    pack_quantity_native: 100

InvenTree/company/migrations/0059_supplierpart_pack_units.py

@@ -0,0 +1,25 @@
+# Generated by Django 3.2.19 on 2023-05-19 03:41
+
+from django.db import migrations, models
+
+import InvenTree.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('company', '0058_auto_20230515_0004'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='supplierpart',
+            name='pack_quantity',
+            field=models.CharField(blank=True, help_text='Total quantity supplied in a single pack. Leave empty for single items.', max_length=25, verbose_name='Pack Quantity'),
+        ),
+        migrations.AddField(
+            model_name='supplierpart',
+            name='pack_quantity_native',
+            field=InvenTree.fields.RoundingDecimalField(decimal_places=10, default=1, max_digits=20, null=True),
+        ),
+    ]

InvenTree/company/migrations/0060_auto_20230519_0344.py

@@ -0,0 +1,51 @@
+# Generated by Django 3.2.19 on 2023-05-19 03:44
+
+from django.db import migrations
+
+from InvenTree.helpers import normalize
+
+
+def update_supplier_part_units(apps, schema_editor):
+    """Migrate existing supplier part units to new field"""
+
+    SupplierPart = apps.get_model('company', 'SupplierPart')
+
+    supplier_parts = SupplierPart.objects.all()
+
+    for sp in supplier_parts:
+        pack_size = normalize(sp.pack_size)
+        sp.pack_quantity = str(pack_size)
+        sp.pack_quantity_native = pack_size
+        sp.save()
+
+    if supplier_parts.count() > 0:
+        print(f"Updated {supplier_parts.count()} supplier part units")
+
+
+def reverse_pack_quantity(apps, schema_editor):
+    """Reverse the migrations"""
+
+    SupplierPart = apps.get_model('company', 'SupplierPart')
+
+    supplier_parts = SupplierPart.objects.all()
+
+    for sp in supplier_parts:
+        sp.pack_size = sp.pack_quantity_native
+        sp.save()
+
+    if supplier_parts.count() > 0:
+        print(f"Updated {supplier_parts.count()} supplier part units")
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('company', '0059_supplierpart_pack_units'),
+        ('part', '0111_auto_20230521_1350'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=update_supplier_part_units,
+            reverse_code=reverse_pack_quantity,
+        )
+    ]

InvenTree/company/migrations/0061_remove_supplierpart_pack_size.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.2.19 on 2023-05-19 04:03
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('company', '0060_auto_20230519_0344'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='supplierpart',
+            name='pack_size',
+        ),
+    ]

InvenTree/company/models.py

@@ -2,6 +2,7 @@
 
 import os
 from datetime import datetime
+from decimal import Decimal
 
 from django.apps import apps
 from django.core.exceptions import ValidationError
@@ -19,6 +20,7 @@ from taggit.managers import TaggableManager
 
 import common.models
 import common.settings
+import InvenTree.conversion
 import InvenTree.fields
 import InvenTree.helpers
 import InvenTree.ready
@@ -436,7 +438,8 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
         multiple: Multiple that the part is provided in
         lead_time: Supplier lead time
         packaging: packaging that the part is supplied in, e.g. "Reel"
-        pack_size: Quantity of item supplied in a single pack (e.g. 30ml in a single tube)
+        pack_quantity: Quantity of item supplied in a single pack (e.g. 30ml in a single tube)
+        pack_quantity_native: Pack quantity, converted to "native" units of the referenced part
         updated: Date that the SupplierPart was last updated
     """
 
@@ -475,6 +478,40 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
         """
         super().clean()
 
+        self.pack_quantity = self.pack_quantity.strip()
+
+        # An empty 'pack_quantity' value is equivalent to '1'
+        if self.pack_quantity == '':
+            self.pack_quantity = '1'
+
+        # Validate that the UOM is compatible with the base part
+        if self.pack_quantity and self.part:
+            try:
+                # Attempt conversion to specified unit
+                native_value = InvenTree.conversion.convert_physical_value(
+                    self.pack_quantity, self.part.units
+                )
+
+                # If part units are not provided, value must be dimensionless
+                if not self.part.units and native_value.units not in ['', 'dimensionless']:
+                    raise ValidationError({
+                        'pack_quantity': _("Pack units must be compatible with the base part units")
+                    })
+
+                # Native value must be greater than zero
+                if float(native_value.magnitude) <= 0:
+                    raise ValidationError({
+                        'pack_quantity': _("Pack units must be greater than zero")
+                    })
+
+                # Update native pack units value
+                self.pack_quantity_native = Decimal(native_value.magnitude)
+
+            except ValidationError as e:
+                raise ValidationError({
+                    'pack_quantity': e.messages
+                })
+
         # Ensure that the linked manufacturer_part points to the same part!
         if self.manufacturer_part and self.part:
 
@@ -510,7 +547,8 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
 
         super().save(*args, **kwargs)
 
-    part = models.ForeignKey('part.Part', on_delete=models.CASCADE,
+    part = models.ForeignKey(
+        'part.Part', on_delete=models.CASCADE,
         related_name='supplier_parts',
         verbose_name=_('Base Part'),
         limit_choices_to={
@@ -519,7 +557,8 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
         help_text=_('Select part'),
     )
 
-    supplier = models.ForeignKey(Company, on_delete=models.CASCADE,
+    supplier = models.ForeignKey(
+        Company, on_delete=models.CASCADE,
         related_name='supplied_parts',
         limit_choices_to={'is_supplier': True},
         verbose_name=_('Supplier'),
@@ -532,7 +571,8 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
         help_text=_('Supplier stock keeping unit')
     )
 
-    manufacturer_part = models.ForeignKey(ManufacturerPart, on_delete=models.CASCADE,
+    manufacturer_part = models.ForeignKey(
+        ManufacturerPart, on_delete=models.CASCADE,
         blank=True, null=True,
         related_name='supplier_parts',
         verbose_name=_('Manufacturer Part'),
@@ -561,14 +601,26 @@ class SupplierPart(MetadataMixin, InvenTreeBarcodeMixin, common.models.MetaMixin
 
     packaging = models.CharField(max_length=50, blank=True, null=True, verbose_name=_('Packaging'), help_text=_('Part packaging'))
 
-    pack_size = RoundingDecimalField(
+    pack_quantity = models.CharField(
+        max_length=25,
         verbose_name=_('Pack Quantity'),
-        help_text=_('Unit quantity supplied in a single pack'),
+        help_text=_('Total quantity supplied in a single pack. Leave empty for single items.'),
-        default=1,
+        blank=True,
-        max_digits=15, decimal_places=5,
-        validators=[MinValueValidator(0.001)],
     )
 
+    pack_quantity_native = RoundingDecimalField(
+        max_digits=20, decimal_places=10, default=1,
+        null=True,
+    )
+
+    def base_quantity(self, quantity=1) -> Decimal:
+        """Calculate the base unit quantiy for a given quantity."""
+
+        q = Decimal(quantity) * Decimal(self.pack_quantity_native)
+        q = round(q, 10).normalize()
+
+        return q
+
     multiple = models.PositiveIntegerField(default=1, validators=[MinValueValidator(1)], verbose_name=_('multiple'), help_text=_('Order multiple'))
 
     # TODO - Reimplement lead-time as a charfield with special validation (pattern matching).

InvenTree/company/serializers.py

@@ -265,7 +265,8 @@ class SupplierPartSerializer(InvenTreeTagModelSerializer):
             'pk',
             'barcode_hash',
             'packaging',
-            'pack_size',
+            'pack_quantity',
+            'pack_quantity_native',
             'part',
             'part_detail',
             'pretty_name',
@@ -327,8 +328,6 @@ class SupplierPartSerializer(InvenTreeTagModelSerializer):
 
     pretty_name = serializers.CharField(read_only=True)
 
-    pack_size = serializers.FloatField(label=_('Pack Quantity'))
-
     supplier = serializers.PrimaryKeyRelatedField(queryset=Company.objects.filter(is_supplier=True))
 
     manufacturer = serializers.CharField(read_only=True)

InvenTree/company/templates/company/supplier_part.html

@@ -162,11 +162,24 @@ src="{% static 'img/blank_image.png' %}"
             <td>{{ part.packaging }}{% include "clip.html" %}</td>
         </tr>
         {% endif %}
-        {% if part.pack_size != 1.0 %}
+        {% if part.pack_quantity %}
         <tr>
             <td><span class='fas fa-box'></span></td>
-            <td>{% trans "Pack Quantity" %}</td>
+            <td>
-            <td>{% decimal part.pack_size %} {% include "part/part_units.html" with part=part.part %}</td>
+                {% trans "Units" %}
+                {% if part.part.units %}
+                <span class='float-right'>
+                    <em>[ {% include "part/part_units.html" with part=part.part %}]</em>
+                </span>
+                {% endif %}
+            </td>
+            <td>
+                {{ part.pack_quantity }}
+                {% include "clip.html" %}
+                {% if part.part.units and part.pack_quantity_native %}
+                <span class='fas fa-info-circle float-right' title='{% decimal part.pack_quantity_native %} {{ part.part.units }}'></span>
+                {% endif %}
+            </td>
         </tr>
         {% endif %}
         {% if part.note %}

InvenTree/company/test_migrations.py

@@ -277,3 +277,51 @@ class TestCurrencyMigration(MigratorTestCase):
         for pb in PB.objects.all():
             # Test that a price has been assigned
             self.assertIsNotNone(pb.price)
+
+
+class TestSupplierPartQuantity(MigratorTestCase):
+    """Test that the supplier part quantity is correctly migrated."""
+
+    migrate_from = ('company', '0058_auto_20230515_0004')
+    migrate_to = ('company', unit_test.getNewestMigrationFile('company'))
+
+    def prepare(self):
+        """Prepare a number of SupplierPart objects"""
+
+        Part = self.old_state.apps.get_model('part', 'part')
+        Company = self.old_state.apps.get_model('company', 'company')
+        SupplierPart = self.old_state.apps.get_model('company', 'supplierpart')
+
+        self.part = Part.objects.create(
+            name="PART", description="A purchaseable part",
+            purchaseable=True,
+            level=0, tree_id=0, lft=0, rght=0
+        )
+
+        self.supplier = Company.objects.create(name='Supplier', description='A supplier', is_supplier=True)
+
+        self.supplier_parts = []
+
+        for i in range(10):
+            self.supplier_parts.append(
+                SupplierPart.objects.create(
+                    part=self.part,
+                    supplier=self.supplier,
+                    SKU=f'SKU-{i}',
+                    pack_size=i + 1,
+                )
+            )
+
+    def test_supplier_part_quantity(self):
+        """Test that the supplier part quantity is correctly migrated."""
+
+        SupplierPart = self.new_state.apps.get_model('company', 'supplierpart')
+
+        for i, sp in enumerate(SupplierPart.objects.all()):
+
+            self.assertEqual(sp.pack_quantity, str(i + 1))
+            self.assertEqual(sp.pack_quantity_native, i + 1)
+
+            # And the 'pack_size' attribute has been removed
+            with self.assertRaises(AttributeError):
+                sp.pack_size

InvenTree/company/test_supplier_parts.py

@@ -0,0 +1,114 @@
+"""Unit tests specific to the SupplierPart model"""
+
+from decimal import Decimal
+
+from django.core.exceptions import ValidationError
+
+from company.models import Company, SupplierPart
+from InvenTree.unit_test import InvenTreeTestCase
+from part.models import Part
+
+
+class SupplierPartPackUnitsTests(InvenTreeTestCase):
+    """Unit tests for the SupplierPart pack_quantity field"""
+
+    def test_pack_quantity_dimensionless(self):
+        """Test valid values for the 'pack_quantity' field"""
+
+        # Create a part without units (dimensionless)
+        part = Part.objects.create(name='Test Part', description='Test part description', component=True)
+
+        # Create a supplier (company)
+        company = Company.objects.create(name='Test Company', is_supplier=True)
+
+        # Create a supplier part for this part
+        sp = SupplierPart.objects.create(
+            part=part,
+            supplier=company,
+            SKU='TEST-SKU'
+        )
+
+        # All these values are valid for a dimensionless part
+        pass_tests = {
+            '': 1,
+            '1': 1,
+            '1.01': 1.01,
+            '12.000001': 12.000001,
+            '99.99': 99.99,
+        }
+
+        # All these values are invalid for a dimensionless part
+        fail_tests = [
+            '1.2m',
+            '-1',
+            '0',
+            '0.0',
+            '100 feet',
+            '0 amps'
+        ]
+
+        for test, expected in pass_tests.items():
+            sp.pack_quantity = test
+            sp.full_clean()
+            self.assertEqual(sp.pack_quantity_native, expected)
+
+        for test in fail_tests:
+            sp.pack_quantity = test
+            with self.assertRaises(ValidationError):
+                sp.full_clean()
+
+    def test_pack_quantity(self):
+        """Test pack_quantity for a part with a specified dimension"""
+
+        # Create a part with units 'm'
+        part = Part.objects.create(name='Test Part', description='Test part description', component=True, units='m')
+
+        # Create a supplier (company)
+        company = Company.objects.create(name='Test Company', is_supplier=True)
+
+        # Create a supplier part for this part
+        sp = SupplierPart.objects.create(
+            part=part,
+            supplier=company,
+            SKU='TEST-SKU'
+        )
+
+        # All these values are valid for a part with dimesion 'm'
+        pass_tests = {
+            '': 1,
+            '1': 1,
+            '1m': 1,
+            '1.01m': 1.01,
+            '1.01': 1.01,
+            '5 inches': 0.127,
+            '27 cm': 0.27,
+            '3km': 3000,
+            '14 feet': 4.2672,
+            '0.5 miles': 804.672,
+        }
+
+        # All these values are invalid for a part with dimension 'm'
+        # Either the values are invalid, or the units are incomaptible
+        fail_tests = [
+            '-1',
+            '-1m',
+            '0',
+            '0m',
+            '12 deg',
+            '57 amps',
+            '-12 oz',
+            '17 yaks',
+        ]
+
+        for test, expected in pass_tests.items():
+            sp.pack_quantity = test
+            sp.full_clean()
+            self.assertEqual(
+                round(Decimal(sp.pack_quantity_native), 10),
+                round(Decimal(str(expected)), 10)
+            )
+
+        for test in fail_tests:
+            sp.pack_quantity = test
+            with self.assertRaises(ValidationError):
+                sp.full_clean()

InvenTree/order/models.py

@@ -602,11 +602,13 @@ class PurchaseOrder(TotalPriceMixin, Order):
         # Create a new stock item
         if line.part and quantity > 0:
 
-            # Take the 'pack_size' of the SupplierPart into account
+            # Calculate received quantity in base units
-            pack_quantity = Decimal(quantity) * Decimal(line.part.pack_size)
+            stock_quantity = line.part.base_quantity(quantity)
 
+            # Calculate unit purchase price (in base units)
             if line.purchase_price:
-                unit_purchase_price = line.purchase_price / line.part.pack_size
+                unit_purchase_price = line.purchase_price
+                unit_purchase_price /= line.part.base_quantity(1)
             else:
                 unit_purchase_price = None
 
@@ -623,7 +625,7 @@ class PurchaseOrder(TotalPriceMixin, Order):
                     part=line.part.part,
                     supplier_part=line.part,
                     location=location,
-                    quantity=1 if serialize else pack_quantity,
+                    quantity=1 if serialize else stock_quantity,
                     purchase_order=self,
                     status=status,
                     batch=batch_code,
@@ -656,7 +658,7 @@ class PurchaseOrder(TotalPriceMixin, Order):
                 )
 
         # Update the number of parts received against the particular line item
-        # Note that this quantity does *not* take the pack_size into account, it is "number of packs"
+        # Note that this quantity does *not* take the pack_quantity into account, it is "number of packs"
         line.received += quantity
         line.save()
 

InvenTree/order/serializers.py

@@ -558,14 +558,12 @@ class PurchaseOrderLineItemReceiveSerializer(serializers.Serializer):
         serial_numbers = data.get('serial_numbers', '').strip()
 
         base_part = line_item.part.part
-        pack_size = line_item.part.pack_size
+        base_quantity = line_item.part.base_quantity(quantity)
-
-        pack_quantity = pack_size * quantity
 
         # Does the quantity need to be "integer" (for trackable parts?)
         if base_part.trackable:
 
-            if Decimal(pack_quantity) != int(pack_quantity):
+            if Decimal(base_quantity) != int(base_quantity):
                 raise ValidationError({
                     'quantity': _('An integer quantity must be provided for trackable parts'),
                 })
@@ -576,7 +574,7 @@ class PurchaseOrderLineItemReceiveSerializer(serializers.Serializer):
                 # Pass the serial numbers through to the parent serializer once validated
                 data['serials'] = extract_serial_numbers(
                     serial_numbers,
-                    pack_quantity,
+                    base_quantity,
                     base_part.get_latest_serial_number()
                 )
             except DjangoValidationError as e:

InvenTree/order/tests.py

@@ -228,7 +228,7 @@ class OrderTest(TestCase):
             part=prt,
             supplier=sup,
             SKU='SKUx10',
-            pack_size=10,
+            pack_quantity='10',
         )
 
         # Create a new supplier part with smaller pack size
@@ -236,7 +236,7 @@ class OrderTest(TestCase):
             part=prt,
             supplier=sup,
             SKU='SKUx0.1',
-            pack_size=0.1,
+            pack_quantity='0.1',
         )
 
         # Record values before we start

InvenTree/part/api.py

@@ -486,10 +486,10 @@ class PartScheduling(RetrieveAPI):
 
             target_date = line.target_date or line.order.target_date
 
-            quantity = max(line.quantity - line.received, 0)
+            line_quantity = max(line.quantity - line.received, 0)
 
-            # Multiply by the pack_size of the SupplierPart
+            # Multiply by the pack quantity of the SupplierPart
-            quantity *= line.part.pack_size
+            quantity = line.part.base_quantity(line_quantity)
 
             add_schedule_entry(
                 target_date,
@@ -804,19 +804,31 @@ class PartFilter(rest_filters.FilterSet):
     Uses the django_filters extension framework
     """
 
+    class Meta:
+        """Metaclass options for this filter set"""
+        model = Part
+        fields = []
+
+    has_units = rest_filters.BooleanFilter(label='Has units', method='filter_has_units')
+
+    def filter_has_units(self, queryset, name, value):
+        """Filter by whether the Part has units or not"""
+
+        if str2bool(value):
+            return queryset.exclude(units='')
+        else:
+            return queryset.filter(units='')
+
     # Filter by parts which have (or not) an IPN value
     has_ipn = rest_filters.BooleanFilter(label='Has IPN', method='filter_has_ipn')
 
     def filter_has_ipn(self, queryset, name, value):
         """Filter by whether the Part has an IPN (internal part number) or not"""
-        value = str2bool(value)
 
-        if value:
+        if str2bool(value):
-            queryset = queryset.exclude(IPN='')
+            return queryset.exclude(IPN='')
         else:
-            queryset = queryset.filter(IPN='')
+            return queryset.filter(IPN='')
-
-        return queryset
 
     # Regex filter for name
     name_regex = rest_filters.CharFilter(label='Filter by name (regex)', field_name='name', lookup_expr='iregex')
@@ -836,46 +848,36 @@ class PartFilter(rest_filters.FilterSet):
 
     def filter_low_stock(self, queryset, name, value):
         """Filter by "low stock" status."""
-        value = str2bool(value)
 
-        if value:
+        if str2bool(value):
             # Ignore any parts which do not have a specified 'minimum_stock' level
-            queryset = queryset.exclude(minimum_stock=0)
             # Filter items which have an 'in_stock' level lower than 'minimum_stock'
-            queryset = queryset.filter(Q(in_stock__lt=F('minimum_stock')))
+            return queryset.exclude(minimum_stock=0).filter(Q(in_stock__lt=F('minimum_stock')))
         else:
             # Filter items which have an 'in_stock' level higher than 'minimum_stock'
-            queryset = queryset.filter(Q(in_stock__gte=F('minimum_stock')))
+            return queryset.filter(Q(in_stock__gte=F('minimum_stock')))
-
-        return queryset
 
     # has_stock filter
     has_stock = rest_filters.BooleanFilter(label='Has stock', method='filter_has_stock')
 
     def filter_has_stock(self, queryset, name, value):
         """Filter by whether the Part has any stock"""
-        value = str2bool(value)
 
-        if value:
+        if str2bool(value):
-            queryset = queryset.filter(Q(in_stock__gt=0))
+            return queryset.filter(Q(in_stock__gt=0))
         else:
-            queryset = queryset.filter(Q(in_stock__lte=0))
+            return queryset.filter(Q(in_stock__lte=0))
-
-        return queryset
 
     # unallocated_stock filter
     unallocated_stock = rest_filters.BooleanFilter(label='Unallocated stock', method='filter_unallocated_stock')
 
     def filter_unallocated_stock(self, queryset, name, value):
         """Filter by whether the Part has unallocated stock"""
-        value = str2bool(value)
 
-        if value:
+        if str2bool(value):
-            queryset = queryset.filter(Q(unallocated_stock__gt=0))
+            return queryset.filter(Q(unallocated_stock__gt=0))
         else:
-            queryset = queryset.filter(Q(unallocated_stock__lte=0))
+            return queryset.filter(Q(unallocated_stock__lte=0))
-
-        return queryset
 
     convert_from = rest_filters.ModelChoiceFilter(label="Can convert from", queryset=Part.objects.all(), method='filter_convert_from')
 
@@ -894,9 +896,7 @@ class PartFilter(rest_filters.FilterSet):
 
         children = part.get_descendants(include_self=True)
 
-        queryset = queryset.exclude(id__in=children)
+        return queryset.exclude(id__in=children)
-
-        return queryset
 
     ancestor = rest_filters.ModelChoiceFilter(label='Ancestor', queryset=Part.objects.all(), method='filter_ancestor')
 
@@ -904,17 +904,14 @@ class PartFilter(rest_filters.FilterSet):
         """Limit queryset to descendants of the specified ancestor part"""
 
         descendants = part.get_descendants(include_self=False)
-        queryset = queryset.filter(id__in=descendants)
+        return queryset.filter(id__in=descendants)
-
-        return queryset
 
     variant_of = rest_filters.ModelChoiceFilter(label='Variant Of', queryset=Part.objects.all(), method='filter_variant_of')
 
     def filter_variant_of(self, queryset, name, part):
         """Limit queryset to direct children (variants) of the specified part"""
 
-        queryset = queryset.filter(id__in=part.get_children())
+        return queryset.filter(id__in=part.get_children())
-        return queryset
 
     in_bom_for = rest_filters.ModelChoiceFilter(label='In BOM Of', queryset=Part.objects.all(), method='filter_in_bom')
 
@@ -922,39 +919,30 @@ class PartFilter(rest_filters.FilterSet):
         """Limit queryset to parts in the BOM for the specified part"""
 
         bom_parts = part.get_parts_in_bom()
-        queryset = queryset.filter(id__in=[p.pk for p in bom_parts])
+        return queryset.filter(id__in=[p.pk for p in bom_parts])
-        return queryset
 
     has_pricing = rest_filters.BooleanFilter(label="Has Pricing", method="filter_has_pricing")
 
     def filter_has_pricing(self, queryset, name, value):
         """Filter the queryset based on whether pricing information is available for the sub_part"""
 
-        value = str2bool(value)
-
         q_a = Q(pricing_data=None)
         q_b = Q(pricing_data__overall_min=None, pricing_data__overall_max=None)
 
-        if value:
+        if str2bool(value):
-            queryset = queryset.exclude(q_a | q_b)
+            return queryset.exclude(q_a | q_b)
         else:
-            queryset = queryset.filter(q_a | q_b)
+            return queryset.filter(q_a | q_b)
-
-        return queryset
 
     stocktake = rest_filters.BooleanFilter(label="Has stocktake", method='filter_has_stocktake')
 
     def filter_has_stocktake(self, queryset, name, value):
         """Filter the queryset based on whether stocktake data is available"""
 
-        value = str2bool(value)
+        if str2bool(value):
-
+            return queryset.exclude(last_stocktake=None)
-        if (value):
-            queryset = queryset.exclude(last_stocktake=None)
         else:
-            queryset = queryset.filter(last_stocktake=None)
+            return queryset.filter(last_stocktake=None)
-
-        return queryset
 
     is_template = rest_filters.BooleanFilter()
 
@@ -1259,6 +1247,7 @@ class PartList(PartMixin, APIDownloadMixin, ListCreateAPI):
         'unallocated_stock',
         'category',
         'last_stocktake',
+        'units',
     ]
 
     # Default ordering

InvenTree/part/filters.py

@@ -40,7 +40,7 @@ def annotate_on_order_quantity(reference: str = ''):
     - Purchase order must be 'active' or 'pending'
     - Received quantity must be less than line item quantity
 
-    Note that in addition to the 'quantity' on order, we must also take into account 'pack_size'.
+    Note that in addition to the 'quantity' on order, we must also take into account 'pack_quantity'.
     """
 
     # Filter only 'active' purhase orders
@@ -53,7 +53,7 @@ def annotate_on_order_quantity(reference: str = ''):
     return Coalesce(
         SubquerySum(
             ExpressionWrapper(
-                F(f'{reference}supplier_parts__purchase_order_line_items__quantity') * F(f'{reference}supplier_parts__pack_size'),
+                F(f'{reference}supplier_parts__purchase_order_line_items__quantity') * F(f'{reference}supplier_parts__pack_quantity_native'),
                 output_field=DecimalField(),
             ),
             filter=order_filter
@@ -63,7 +63,7 @@ def annotate_on_order_quantity(reference: str = ''):
     ) - Coalesce(
         SubquerySum(
             ExpressionWrapper(
-                F(f'{reference}supplier_parts__purchase_order_line_items__received') * F(f'{reference}supplier_parts__pack_size'),
+                F(f'{reference}supplier_parts__purchase_order_line_items__received') * F(f'{reference}supplier_parts__pack_quantity_native'),
                 output_field=DecimalField(),
             ),
             filter=order_filter

InvenTree/part/migrations/0109_auto_20230517_1048.py

@@ -19,10 +19,14 @@ def update_template_units(apps, schema_editor):
 
     n_templates = PartParameterTemplate.objects.count()
 
+    if n_templates == 0:
+        # Escape early
+        return
+
     ureg = InvenTree.conversion.get_unit_registry()
 
     n_converted = 0
-    invalid_units = []
+    invalid_units = set()
 
     for template in PartParameterTemplate.objects.all():
 
@@ -69,8 +73,8 @@ def update_template_units(apps, schema_editor):
                 break
 
         if not found:
-            print(f"warningCould not find unit match for {template.units}")
+            print(f"warning: Could not find unit match for {template.units}")
-            invalid_units.append(template.units)
+            invalid_units.add(template.units)
 
     print(f"Updated units for {n_templates} parameter templates")
 

InvenTree/part/migrations/0110_alter_part_units.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.19 on 2023-05-19 03:31
+
+import InvenTree.validators
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0109_auto_20230517_1048'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='part',
+            name='units',
+            field=models.CharField(blank=True, default='', help_text='Units of measure for this part', max_length=20, null=True, validators=[InvenTree.validators.validate_physical_units], verbose_name='Units'),
+        ),
+    ]

InvenTree/part/migrations/0111_auto_20230521_1350.py

@@ -0,0 +1,93 @@
+# Generated by Django 3.2.19 on 2023-05-21 13:50
+
+import pint
+
+from django.core.exceptions import ValidationError
+from django.db import migrations
+
+import InvenTree.conversion
+
+
+def migrate_part_units(apps, schema_editor):
+    """Update the units field for each Part object:
+
+    - Check if the units are valid
+    - Attempt to convert to valid units (if possible)
+    """
+
+    Part = apps.get_model('part', 'Part')
+
+    parts = Part.objects.exclude(units=None).exclude(units='')
+    n_parts = parts.count()
+
+    if n_parts == 0:
+        # Escape early
+        return
+
+    ureg = InvenTree.conversion.get_unit_registry()
+
+    invalid_units = set()
+    n_converted = 0
+
+    for part in parts:
+
+        # Override '%' units (which are invalid)
+        if part.units == '%':
+            part.units = 'percent'
+            part.save()
+            continue
+
+        # Test if unit is 'valid'
+        try:
+            ureg.Unit(part.units)
+            continue
+        except pint.errors.UndefinedUnitError:
+            pass
+
+        # Check a lower-case version
+        try:
+            ureg.Unit(part.units.lower())
+            print(f"Found unit match: {part.units} -> {part.units.lower()}")
+            part.units = part.units.lower()
+            part.save()
+            n_converted += 1
+            continue
+        except pint.errors.UndefinedUnitError:
+            pass
+
+        found = False
+
+        # Attempt to convert to a valid unit
+        for unit in ureg:
+            if unit.lower() == part.units.lower():
+                print("Found unit match: {part.units} -> {unit}")
+                part.units = str(unit)
+                part.save()
+                n_converted += 1
+                found = True
+                break
+
+        if not found:
+            print(f"Warning: Invalid units for part '{part}': {part.units}")
+            invalid_units.add(part.units)
+
+    print(f"Updated units for {n_parts} parts")
+
+    if n_converted > 0:
+        print(f"Converted units for {n_converted} parts")
+
+    if len(invalid_units) > 0:
+        print(f"Found {len(invalid_units)} invalid units:")
+        for unit in invalid_units:
+            print(f" - {unit}")
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('part', '0110_alter_part_units'),
+    ]
+
+    operations = [
+        migrations.RunPython(code=migrate_part_units, reverse_code=migrations.RunPython.noop)
+    ]

InvenTree/part/models.py

@@ -984,6 +984,9 @@ class Part(InvenTreeBarcodeMixin, InvenTreeNotesMixin, MetadataMixin, MPTTModel)
         blank=True, null=True,
         verbose_name=_('Units'),
         help_text=_('Units of measure for this part'),
+        validators=[
+            validators.validate_physical_units,
+        ]
     )
 
     assembly = models.BooleanField(
@@ -2141,7 +2144,7 @@ class Part(InvenTreeBarcodeMixin, InvenTreeNotesMixin, MetadataMixin, MPTTModel)
     def on_order(self):
         """Return the total number of items on order for this part.
 
-        Note that some supplier parts may have a different pack_size attribute,
+        Note that some supplier parts may have a different pack_quantity attribute,
         and this needs to be taken into account!
         """
 
@@ -2160,7 +2163,7 @@ class Part(InvenTreeBarcodeMixin, InvenTreeNotesMixin, MetadataMixin, MPTTModel)
                 remaining = line.quantity - line.received
 
                 if remaining > 0:
-                    quantity += remaining * sp.pack_size
+                    quantity += sp.base_quantity(remaining)
 
         return quantity
 
@@ -2291,6 +2294,13 @@ def after_save_part(sender, instance: Part, created, **kwargs):
             # Can sometimes occur if the referenced Part has issues
             pass
 
+        # Schedule a background task to rebuild any supplier parts
+        InvenTree.tasks.offload_task(
+            part_tasks.rebuild_supplier_parts,
+            instance.pk,
+            force_async=True
+        )
+
 
 class PartPricing(common.models.MetaMixin):
     """Model for caching min/max pricing information for a particular Part
@@ -2560,7 +2570,7 @@ class PartPricing(common.models.MetaMixin):
                 continue
 
             # Take supplier part pack size into account
-            purchase_cost = self.convert(line.purchase_price / line.part.pack_size)
+            purchase_cost = self.convert(line.purchase_price / line.part.pack_quantity_native)
 
             if purchase_cost is None:
                 continue
@@ -2651,7 +2661,7 @@ class PartPricing(common.models.MetaMixin):
                         continue
 
                     # Ensure we take supplier part pack size into account
-                    cost = self.convert(pb.price / sp.pack_size)
+                    cost = self.convert(pb.price / sp.pack_quantity_native)
 
                     if cost is None:
                         continue
@@ -3359,8 +3369,8 @@ def post_save_part_parameter_template(sender, instance, created, **kwargs):
 
     if InvenTree.ready.canAppAccessDatabase() and not InvenTree.ready.isImportingData():
 
-        # Schedule a background task to rebuild the parameters against this template
         if not created:
+            # Schedule a background task to rebuild the parameters against this template
             InvenTree.tasks.offload_task(
                 part_tasks.rebuild_parameters,
                 instance.pk,

InvenTree/part/serializers.py

@@ -20,21 +20,11 @@ from taggit.serializers import TagListSerializerField
 import common.models
 import company.models
 import InvenTree.helpers
+import InvenTree.serializers
 import InvenTree.status
 import part.filters
 import part.tasks
 import stock.models
-from InvenTree.serializers import (DataFileExtractSerializer,
-                                   DataFileUploadSerializer,
-                                   InvenTreeAttachmentSerializer,
-                                   InvenTreeAttachmentSerializerField,
-                                   InvenTreeCurrencySerializer,
-                                   InvenTreeDecimalField,
-                                   InvenTreeImageSerializerField,
-                                   InvenTreeModelSerializer,
-                                   InvenTreeMoneySerializer,
-                                   InvenTreeTagModelSerializer,
-                                   RemoteImageMixin, UserSerializer)
 from InvenTree.status_codes import BuildStatus
 from InvenTree.tasks import offload_task
 
@@ -48,7 +38,7 @@ from .models import (BomItem, BomItemSubstitute, Part, PartAttachment,
 logger = logging.getLogger("inventree")
 
 
-class CategorySerializer(InvenTreeModelSerializer):
+class CategorySerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for PartCategory."""
 
     class Meta:
@@ -94,7 +84,7 @@ class CategorySerializer(InvenTreeModelSerializer):
     starred = serializers.SerializerMethodField()
 
 
-class CategoryTree(InvenTreeModelSerializer):
+class CategoryTree(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for PartCategory tree."""
 
     class Meta:
@@ -108,19 +98,19 @@ class CategoryTree(InvenTreeModelSerializer):
         ]
 
 
-class PartAttachmentSerializer(InvenTreeAttachmentSerializer):
+class PartAttachmentSerializer(InvenTree.serializers.InvenTreeAttachmentSerializer):
     """Serializer for the PartAttachment class."""
 
     class Meta:
         """Metaclass defining serializer fields"""
         model = PartAttachment
 
-        fields = InvenTreeAttachmentSerializer.attachment_fields([
+        fields = InvenTree.serializers.InvenTreeAttachmentSerializer.attachment_fields([
             'part',
         ])
 
 
-class PartTestTemplateSerializer(InvenTreeModelSerializer):
+class PartTestTemplateSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for the PartTestTemplate class."""
 
     class Meta:
@@ -141,7 +131,7 @@ class PartTestTemplateSerializer(InvenTreeModelSerializer):
     key = serializers.CharField(read_only=True)
 
 
-class PartSalePriceSerializer(InvenTreeModelSerializer):
+class PartSalePriceSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for sale prices for Part model."""
 
     class Meta:
@@ -155,14 +145,14 @@ class PartSalePriceSerializer(InvenTreeModelSerializer):
             'price_currency',
         ]
 
-    quantity = InvenTreeDecimalField()
+    quantity = InvenTree.serializers.InvenTreeDecimalField()
 
-    price = InvenTreeMoneySerializer(allow_null=True)
+    price = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True)
 
-    price_currency = InvenTreeCurrencySerializer(help_text=_('Purchase currency of this stock item'))
+    price_currency = InvenTree.serializers.InvenTreeCurrencySerializer(help_text=_('Purchase currency of this stock item'))
 
 
-class PartInternalPriceSerializer(InvenTreeModelSerializer):
+class PartInternalPriceSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for internal prices for Part model."""
 
     class Meta:
@@ -176,13 +166,13 @@ class PartInternalPriceSerializer(InvenTreeModelSerializer):
             'price_currency',
         ]
 
-    quantity = InvenTreeDecimalField()
+    quantity = InvenTree.serializers.InvenTreeDecimalField()
 
-    price = InvenTreeMoneySerializer(
+    price = InvenTree.serializers.InvenTreeMoneySerializer(
         allow_null=True
     )
 
-    price_currency = InvenTreeCurrencySerializer(help_text=_('Purchase currency of this stock item'))
+    price_currency = InvenTree.serializers.InvenTreeCurrencySerializer(help_text=_('Purchase currency of this stock item'))
 
 
 class PartThumbSerializer(serializers.Serializer):
@@ -195,7 +185,7 @@ class PartThumbSerializer(serializers.Serializer):
     count = serializers.IntegerField(read_only=True)
 
 
-class PartThumbSerializerUpdate(InvenTreeModelSerializer):
+class PartThumbSerializerUpdate(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for updating Part thumbnail."""
 
     class Meta:
@@ -212,10 +202,10 @@ class PartThumbSerializerUpdate(InvenTreeModelSerializer):
             raise serializers.ValidationError("File is not an image")
         return value
 
-    image = InvenTreeAttachmentSerializerField(required=True)
+    image = InvenTree.serializers.InvenTreeAttachmentSerializerField(required=True)
 
 
-class PartParameterTemplateSerializer(InvenTreeModelSerializer):
+class PartParameterTemplateSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """JSON serializer for the PartParameterTemplate model."""
 
     class Meta:
@@ -229,7 +219,7 @@ class PartParameterTemplateSerializer(InvenTreeModelSerializer):
         ]
 
 
-class PartParameterSerializer(InvenTreeModelSerializer):
+class PartParameterSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """JSON serializers for the PartParameter model."""
 
     class Meta:
@@ -260,7 +250,7 @@ class PartParameterSerializer(InvenTreeModelSerializer):
     template_detail = PartParameterTemplateSerializer(source='template', many=False, read_only=True)
 
 
-class PartBriefSerializer(InvenTreeModelSerializer):
+class PartBriefSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for Part (brief detail)"""
 
     class Meta:
@@ -295,8 +285,8 @@ class PartBriefSerializer(InvenTreeModelSerializer):
     thumbnail = serializers.CharField(source='get_thumbnail_url', read_only=True)
 
     # Pricing fields
-    pricing_min = InvenTreeMoneySerializer(source='pricing_data.overall_min', allow_null=True, read_only=True)
+    pricing_min = InvenTree.serializers.InvenTreeMoneySerializer(source='pricing_data.overall_min', allow_null=True, read_only=True)
-    pricing_max = InvenTreeMoneySerializer(source='pricing_data.overall_max', allow_null=True, read_only=True)
+    pricing_max = InvenTree.serializers.InvenTreeMoneySerializer(source='pricing_data.overall_max', allow_null=True, read_only=True)
 
 
 class DuplicatePartSerializer(serializers.Serializer):
@@ -406,7 +396,7 @@ class InitialSupplierSerializer(serializers.Serializer):
         return data
 
 
-class PartSerializer(RemoteImageMixin, InvenTreeTagModelSerializer):
+class PartSerializer(InvenTree.serializers.RemoteImageMixin, InvenTree.serializers.InvenTreeTagModelSerializer):
     """Serializer for complete detail information of a part.
 
     Used when displaying all details of a single component.
@@ -607,7 +597,7 @@ class PartSerializer(RemoteImageMixin, InvenTreeTagModelSerializer):
     stock_item_count = serializers.IntegerField(read_only=True)
     suppliers = serializers.IntegerField(read_only=True)
 
-    image = InvenTreeImageSerializerField(required=False, allow_null=True)
+    image = InvenTree.serializers.InvenTreeImageSerializerField(required=False, allow_null=True)
     thumbnail = serializers.CharField(source='get_thumbnail_url', read_only=True)
     starred = serializers.SerializerMethodField()
 
@@ -615,8 +605,8 @@ class PartSerializer(RemoteImageMixin, InvenTreeTagModelSerializer):
     category = serializers.PrimaryKeyRelatedField(queryset=PartCategory.objects.all())
 
     # Pricing fields
-    pricing_min = InvenTreeMoneySerializer(source='pricing_data.overall_min', allow_null=True, read_only=True)
+    pricing_min = InvenTree.serializers.InvenTreeMoneySerializer(source='pricing_data.overall_min', allow_null=True, read_only=True)
-    pricing_max = InvenTreeMoneySerializer(source='pricing_data.overall_max', allow_null=True, read_only=True)
+    pricing_max = InvenTree.serializers.InvenTreeMoneySerializer(source='pricing_data.overall_max', allow_null=True, read_only=True)
 
     parameters = PartParameterSerializer(
         many=True,
@@ -771,7 +761,7 @@ class PartSerializer(RemoteImageMixin, InvenTreeTagModelSerializer):
         return self.instance
 
 
-class PartStocktakeSerializer(InvenTreeModelSerializer):
+class PartStocktakeSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for the PartStocktake model"""
 
     class Meta:
@@ -800,13 +790,13 @@ class PartStocktakeSerializer(InvenTreeModelSerializer):
 
     quantity = serializers.FloatField()
 
-    user_detail = UserSerializer(source='user', read_only=True, many=False)
+    user_detail = InvenTree.serializers.UserSerializer(source='user', read_only=True, many=False)
 
-    cost_min = InvenTreeMoneySerializer(allow_null=True)
+    cost_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True)
-    cost_min_currency = InvenTreeCurrencySerializer()
+    cost_min_currency = InvenTree.serializers.InvenTreeCurrencySerializer()
 
-    cost_max = InvenTreeMoneySerializer(allow_null=True)
+    cost_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True)
-    cost_max_currency = InvenTreeCurrencySerializer()
+    cost_max_currency = InvenTree.serializers.InvenTreeCurrencySerializer()
 
     def save(self):
         """Called when this serializer is saved"""
@@ -820,7 +810,7 @@ class PartStocktakeSerializer(InvenTreeModelSerializer):
         super().save()
 
 
-class PartStocktakeReportSerializer(InvenTreeModelSerializer):
+class PartStocktakeReportSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for stocktake report class"""
 
     class Meta:
@@ -836,9 +826,9 @@ class PartStocktakeReportSerializer(InvenTreeModelSerializer):
             'user_detail',
         ]
 
-    user_detail = UserSerializer(source='user', read_only=True, many=False)
+    user_detail = InvenTree.serializers.UserSerializer(source='user', read_only=True, many=False)
 
-    report = InvenTreeAttachmentSerializerField(read_only=True)
+    report = InvenTree.serializers.InvenTreeAttachmentSerializerField(read_only=True)
 
 
 class PartStocktakeReportGenerateSerializer(serializers.Serializer):
@@ -906,7 +896,7 @@ class PartStocktakeReportGenerateSerializer(serializers.Serializer):
         )
 
 
-class PartPricingSerializer(InvenTreeModelSerializer):
+class PartPricingSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for Part pricing information"""
 
     class Meta:
@@ -942,29 +932,29 @@ class PartPricingSerializer(InvenTreeModelSerializer):
     scheduled_for_update = serializers.BooleanField(read_only=True)
 
     # Custom serializers
-    bom_cost_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    bom_cost_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    bom_cost_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    bom_cost_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    purchase_cost_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    purchase_cost_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    purchase_cost_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    purchase_cost_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    internal_cost_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    internal_cost_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    internal_cost_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    internal_cost_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    supplier_price_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    supplier_price_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    supplier_price_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    supplier_price_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    variant_cost_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    variant_cost_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    variant_cost_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    variant_cost_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    overall_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    overall_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    overall_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    overall_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    sale_price_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    sale_price_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    sale_price_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    sale_price_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
-    sale_history_min = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    sale_history_min = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
-    sale_history_max = InvenTreeMoneySerializer(allow_null=True, read_only=True)
+    sale_history_max = InvenTree.serializers.InvenTreeMoneySerializer(allow_null=True, read_only=True)
 
     update = serializers.BooleanField(
         write_only=True,
@@ -984,7 +974,7 @@ class PartPricingSerializer(InvenTreeModelSerializer):
             pricing.update_pricing()
 
 
-class PartRelationSerializer(InvenTreeModelSerializer):
+class PartRelationSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for a PartRelated model."""
 
     class Meta:
@@ -1002,7 +992,7 @@ class PartRelationSerializer(InvenTreeModelSerializer):
     part_2_detail = PartSerializer(source='part_2', read_only=True, many=False)
 
 
-class PartStarSerializer(InvenTreeModelSerializer):
+class PartStarSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for a PartStar object."""
 
     class Meta:
@@ -1020,7 +1010,7 @@ class PartStarSerializer(InvenTreeModelSerializer):
     username = serializers.CharField(source='user.username', read_only=True)
 
 
-class BomItemSubstituteSerializer(InvenTreeModelSerializer):
+class BomItemSubstituteSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for the BomItemSubstitute class."""
 
     class Meta:
@@ -1036,7 +1026,7 @@ class BomItemSubstituteSerializer(InvenTreeModelSerializer):
     part_detail = PartBriefSerializer(source='part', read_only=True, many=False)
 
 
-class BomItemSerializer(InvenTreeModelSerializer):
+class BomItemSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for BomItem object."""
 
     class Meta:
@@ -1087,7 +1077,7 @@ class BomItemSerializer(InvenTreeModelSerializer):
         if sub_part_detail is not True:
             self.fields.pop('sub_part_detail')
 
-    quantity = InvenTreeDecimalField(required=True)
+    quantity = InvenTree.serializers.InvenTreeDecimalField(required=True)
 
     def validate_quantity(self, quantity):
         """Perform validation for the BomItem quantity field"""
@@ -1109,8 +1099,8 @@ class BomItemSerializer(InvenTreeModelSerializer):
     on_order = serializers.FloatField(read_only=True)
 
     # Cached pricing fields
-    pricing_min = InvenTreeMoneySerializer(source='sub_part.pricing.overall_min', allow_null=True, read_only=True)
+    pricing_min = InvenTree.serializers.InvenTreeMoneySerializer(source='sub_part.pricing.overall_min', allow_null=True, read_only=True)
-    pricing_max = InvenTreeMoneySerializer(source='sub_part.pricing.overall_max', allow_null=True, read_only=True)
+    pricing_max = InvenTree.serializers.InvenTreeMoneySerializer(source='sub_part.pricing.overall_max', allow_null=True, read_only=True)
 
     # Annotated fields for available stock
     available_stock = serializers.FloatField(read_only=True)
@@ -1212,7 +1202,7 @@ class BomItemSerializer(InvenTreeModelSerializer):
         return queryset
 
 
-class CategoryParameterTemplateSerializer(InvenTreeModelSerializer):
+class CategoryParameterTemplateSerializer(InvenTree.serializers.InvenTreeModelSerializer):
     """Serializer for the PartCategoryParameterTemplate model."""
 
     class Meta:
@@ -1297,7 +1287,7 @@ class PartCopyBOMSerializer(serializers.Serializer):
         )
 
 
-class BomImportUploadSerializer(DataFileUploadSerializer):
+class BomImportUploadSerializer(InvenTree.serializers.DataFileUploadSerializer):
     """Serializer for uploading a file and extracting data from it."""
 
     TARGET_MODEL = BomItem
@@ -1333,7 +1323,7 @@ class BomImportUploadSerializer(DataFileUploadSerializer):
                 part.bom_items.all().delete()
 
 
-class BomImportExtractSerializer(DataFileExtractSerializer):
+class BomImportExtractSerializer(InvenTree.serializers.DataFileExtractSerializer):
     """Serializer class for exatracting BOM data from an uploaded file.
 
     The parent class DataFileExtractSerializer does most of the heavy lifting here.

InvenTree/part/tasks.py

@@ -7,6 +7,7 @@ import time
 from datetime import datetime, timedelta
 
 from django.contrib.auth.models import User
+from django.core.exceptions import ValidationError
 from django.core.files.base import ContentFile
 from django.utils.translation import gettext_lazy as _
 
@@ -18,6 +19,7 @@ from djmoney.money import Money
 import common.models
 import common.notifications
 import common.settings
+import company.models
 import InvenTree.helpers
 import InvenTree.tasks
 import part.models
@@ -433,7 +435,7 @@ def scheduled_stocktake_reports():
 def rebuild_parameters(template_id):
     """Rebuild all parameters for a given template.
 
-    This method is called when a base template is changed,
+    This function is called when a base template is changed,
     which may cause the base unit to be adjusted.
     """
 
@@ -452,7 +454,35 @@ def rebuild_parameters(template_id):
         parameter.calculate_numeric_value()
 
         if value_old != parameter.data_numeric:
+            parameter.full_clean()
             parameter.save()
             n += 1
 
     logger.info(f"Rebuilt {n} parameters for template '{template.name}'")
+
+
+def rebuild_supplier_parts(part_id):
+    """Rebuild all SupplierPart objects for a given part.
+
+    This function is called when a bart part is changed,
+    which may cause the native units of any supplier parts to be updated
+    """
+
+    try:
+        prt = part.models.Part.objects.get(pk=part_id)
+    except part.models.Part.DoesNotExist:
+        return
+
+    supplier_parts = company.models.SupplierPart.objects.filter(part=prt)
+
+    n = supplier_parts.count()
+
+    for supplier_part in supplier_parts:
+        # Re-save the part, to ensure that the units have updated correctly
+        try:
+            supplier_part.full_clean()
+            supplier_part.save()
+        except ValidationError:
+            pass
+
+    logger.info(f"Rebuilt {n} supplier parts for part '{prt.name}'")

InvenTree/part/test_api.py

@@ -2144,7 +2144,7 @@ class PartAPIAggregationTest(InvenTreeAPITestCase):
                     part=p,
                     supplier=supplier,
                     SKU=f"PNT-{color}-{pk_sz}L",
-                    pack_size=pk_sz,
+                    pack_quantity=str(pk_sz),
                 )
 
             self.assertEqual(p.supplier_parts.count(), 4)
@@ -2206,7 +2206,7 @@ class PartAPIAggregationTest(InvenTreeAPITestCase):
                         remaining = line_item.quantity - line_item.received
 
                         if remaining > 0:
-                            on_order += remaining * sp.pack_size
+                            on_order += sp.base_quantity(remaining)
 
             # The annotated quantity must be equal to the hand-calculated quantity
             self.assertEqual(on_order, item['ordering'])

InvenTree/part/test_migrations.py

@@ -88,7 +88,7 @@ class TestParameterMigrations(MigratorTestCase):
     """Unit test for part parameter migrations"""
 
     migrate_from = ('part', '0106_part_tags')
-    migrate_to = ('part', '0109_auto_20230517_1048')
+    migrate_to = ('part', unit_test.getNewestMigrationFile('part'))
 
     def prepare(self):
         """Create some parts, and templates with parameters"""
@@ -154,3 +154,38 @@ class TestParameterMigrations(MigratorTestCase):
         p4 = PartParameter.objects.get(part=b, template=t2)
         self.assertEqual(p4.data, 'abc')
         self.assertEqual(p4.data_numeric, None)
+
+
+class PartUnitsMigrationTest(MigratorTestCase):
+    """Test for data migration of Part.units field"""
+
+    migrate_from = ('part', '0109_auto_20230517_1048')
+    migrate_to = ('part', unit_test.getNewestMigrationFile('part'))
+
+    def prepare(self):
+        """Prepare some parts with units"""
+
+        Part = self.old_state.apps.get_model('part', 'part')
+
+        units = ['mm', 'INCH', '', '%']
+
+        for idx, unit in enumerate(units):
+            Part.objects.create(
+                name=f'Part {idx + 1}', description=f'My part at index {idx}', units=unit,
+                level=0, lft=0, rght=0, tree_id=0,
+            )
+
+    def test_units_migration(self):
+        """Test that the units have migrated OK"""
+
+        Part = self.new_state.apps.get_model('part', 'part')
+
+        part_1 = Part.objects.get(name='Part 1')
+        part_2 = Part.objects.get(name='Part 2')
+        part_3 = Part.objects.get(name='Part 3')
+        part_4 = Part.objects.get(name='Part 4')
+
+        self.assertEqual(part_1.units, 'mm')
+        self.assertEqual(part_2.units, 'inch')
+        self.assertEqual(part_3.units, '')
+        self.assertEqual(part_4.units, 'percent')

InvenTree/part/test_pricing.py

@@ -2,6 +2,7 @@
 
 from django.core.exceptions import ObjectDoesNotExist
 
+from djmoney.contrib.exchange.models import convert_money
 from djmoney.money import Money
 
 import common.models
@@ -25,10 +26,13 @@ class PartPricingTests(InvenTreeTestCase):
         self.generate_exchange_rates()
 
         # Create a new part for performing pricing calculations
+        # We will use 'metres' for the UOM here
+        # Some SupplierPart instances will have different units!
         self.part = part.models.Part.objects.create(
             name='PP',
-            description='A part with pricing',
+            description='A part with pricing, measured in metres',
-            assembly=True
+            assembly=True,
+            units='m'
         )
 
     def create_price_breaks(self):
@@ -44,8 +48,12 @@ class PartPricingTests(InvenTreeTestCase):
             supplier=self.supplier_1,
             part=self.part,
             SKU='SUP_1',
+            pack_quantity='200 cm',
         )
 
+        # Native pack quantity should be 2m
+        self.assertEqual(self.sp_1.pack_quantity_native, 2)
+
         company.models.SupplierPriceBreak.objects.create(
             part=self.sp_1,
             quantity=1,
@@ -63,16 +71,22 @@ class PartPricingTests(InvenTreeTestCase):
             supplier=self.supplier_2,
             part=self.part,
             SKU='SUP_2',
-            pack_size=2.5,
+            pack_quantity='2.5',
         )
 
+        # Native pack quantity should be 2.5m
+        self.assertEqual(self.sp_2.pack_quantity_native, 2.5)
+
         self.sp_3 = company.models.SupplierPart.objects.create(
             supplier=self.supplier_2,
             part=self.part,
             SKU='SUP_3',
-            pack_size=10
+            pack_quantity='10 inches',
         )
 
+        # Native pack quantity should be 0.254m
+        self.assertEqual(self.sp_3.pack_quantity_native, 0.254)
+
         company.models.SupplierPriceBreak.objects.create(
             part=self.sp_2,
             quantity=5,
@@ -162,8 +176,8 @@ class PartPricingTests(InvenTreeTestCase):
 
         pricing.update_pricing()
 
-        self.assertEqual(pricing.overall_min, Money('2.014667', 'USD'))
+        self.assertAlmostEqual(float(pricing.overall_min.amount), 2.015, places=2)
-        self.assertEqual(pricing.overall_max, Money('6.117647', 'USD'))
+        self.assertAlmostEqual(float(pricing.overall_max.amount), 3.06, places=2)
 
         # Delete all supplier parts and re-calculate
         self.part.supplier_parts.all().delete()
@@ -319,11 +333,11 @@ class PartPricingTests(InvenTreeTestCase):
 
         # Add some line items to the order
 
-        # $5 AUD each
+        # $5 AUD each @ 2.5m per unit = $2 AUD per metre
         line_1 = po.add_line_item(self.sp_2, quantity=10, purchase_price=Money(5, 'AUD'))
 
-        # $30 CAD each (but pack_size is 10, so really $3 CAD each)
+        # $3 CAD each @ 10 inches per unit = $0.3 CAD per inch = $11.81 CAD per metre
-        line_2 = po.add_line_item(self.sp_3, quantity=5, purchase_price=Money(30, 'CAD'))
+        line_2 = po.add_line_item(self.sp_3, quantity=5, purchase_price=Money(3, 'CAD'))
 
         pricing.update_purchase_cost()
 
@@ -349,8 +363,20 @@ class PartPricingTests(InvenTreeTestCase):
 
         pricing.update_purchase_cost()
 
-        self.assertEqual(pricing.purchase_cost_min, Money('1.333333', 'USD'))
+        min_cost_aud = convert_money(pricing.purchase_cost_min, 'AUD')
-        self.assertEqual(pricing.purchase_cost_max, Money('1.764706', 'USD'))
+        max_cost_cad = convert_money(pricing.purchase_cost_max, 'CAD')
+
+        # Min cost in AUD = $2 AUD per metre
+        self.assertAlmostEqual(float(min_cost_aud.amount), 2, places=2)
+
+        # Min cost in USD
+        self.assertAlmostEqual(float(pricing.purchase_cost_min.amount), 1.3333, places=2)
+
+        # Max cost in CAD = $11.81 CAD per metre
+        self.assertAlmostEqual(float(max_cost_cad.amount), 11.81, places=2)
+
+        # Max cost in USD
+        self.assertAlmostEqual(float(pricing.purchase_cost_max.amount), 6.95, places=2)
 
     def test_delete_with_pricing(self):
         """Test for deleting a part which has pricing information"""

InvenTree/stock/api.py

@@ -613,7 +613,7 @@ class StockList(APIDownloadMixin, ListCreateDestroyAPIView):
                     'supplier_part': _('The given supplier part does not exist'),
                 })
 
-            if supplier_part.pack_size != 1:
+            if supplier_part.base_quantity() != 1:
                 # Skip this check if pack size is 1 - makes no difference
                 # use_pack_size = True -> Multiply quantity by pack size
                 # use_pack_size = False -> Use quantity as is
@@ -623,10 +623,9 @@ class StockList(APIDownloadMixin, ListCreateDestroyAPIView):
                     })
                 else:
                     if bool(data.get('use_pack_size')):
-                        data['quantity'] = int(quantity) * float(supplier_part.pack_size)
+                        quantity = data['quantity'] = supplier_part.base_quantity(quantity)
-                        quantity = data.get('quantity', None)
                         # Divide purchase price by pack size, to save correct price per stock item
-                        data['purchase_price'] = float(data['purchase_price']) / float(supplier_part.pack_size)
+                        data['purchase_price'] = float(data['purchase_price']) / float(supplier_part.pack_quantity_native)
 
         # Now remove the flag from data, so that it doesn't interfere with saving
         # Do this regardless of results above

InvenTree/stock/migrations/0094_auto_20230220_0025.py

@@ -2,6 +2,7 @@
 
 import logging
 
+from django.core.exceptions import FieldError
 from django.db import migrations
 
 logger = logging.getLogger('inventree')
@@ -38,10 +39,13 @@ def fix_purchase_price(apps, schema_editor):
         supplier_part=None
     ).exclude(
         purchase_price=None
-    ).exclude(
-        supplier_part__pack_size=1
     )
 
+    try:
+        items = items.exclude(supplier_part__pack_size=1)
+    except FieldError:
+        pass
+
     n_updated = 0
 
     for item in items:

InvenTree/stock/test_api.py

@@ -698,6 +698,7 @@ class StockItemTest(StockAPITestCase):
             },
             expected_code=201
         )
+
         # Reload part, count stock again
         part_4 = part.models.Part.objects.get(pk=4)
         self.assertEqual(part_4.available_stock, current_count + 3)

InvenTree/templates/js/translated/company.js

@@ -138,7 +138,7 @@ function supplierPartFields(options={}) {
         packaging: {
             icon: 'fa-box',
         },
-        pack_size: {},
+        pack_quantity: {},
     };
 
     if (options.part) {
@@ -1242,17 +1242,24 @@ function loadSupplierPartTable(table, url, options) {
                 sortable: true,
             },
             {
-                field: 'pack_size',
+                field: 'pack_quantity',
                 title: '{% trans "Pack Quantity" %}',
                 sortable: true,
                 formatter: function(value, row) {
-                    var output = `${value}`;
 
-                    if (row.part_detail && row.part_detail.units) {
+                    let html = '';
-                        output += ` ${row.part_detail.units}`;
+
+                    if (value) {
+                        html = value;
+                    } else {
+                        html = '-';
                     }
 
-                    return output;
+                    if (row.part_detail && row.part_detail.units) {
+                        html += `<span class='fas fa-info-circle float-right' title='{% trans "Base Units" %}: ${row.part_detail.units}'></span>`;
+                    }
+
+                    return html;
                 }
             },
             {

InvenTree/templates/js/translated/part.js

@@ -1588,13 +1588,12 @@ function loadPartPurchaseOrderTable(table, part_id, options={}) {
                 formatter: function(value, row) {
                     let data = value;
 
-                    if (row.supplier_part_detail.pack_size != 1.0) {
+                    if (row.supplier_part_detail.pack_quantity_native != 1.0) {
-                        let pack_size = row.supplier_part_detail.pack_size;
+                        let total = value * row.supplier_part_detail.pack_quantity_native;
-                        let total = value * pack_size;
 
                         data += makeIconBadge(
                             'fa-info-circle icon-blue',
-                            `{% trans "Pack Quantity" %}: ${pack_size} - {% trans "Total Quantity" %}: ${total}`
+                            `{% trans "Pack Quantity" %}: ${formatDecimal(row.pack_quantity)} - {% trans "Total Quantity" %}: ${total}`
                         );
                     }
 
@@ -1647,10 +1646,9 @@ function loadPartPurchaseOrderTable(table, part_id, options={}) {
                 formatter: function(value, row) {
                     var data = value;
 
-                    if (value > 0 && row.supplier_part_detail.pack_size != 1.0) {
+                    if (value > 0 && row.supplier_part_detail.pack_quantity_native != 1.0) {
-                        var pack_size = row.supplier_part_detail.pack_size;
+                        let total = value * row.supplier_part_detail.pack_quantity_native;
-                        var total = value * pack_size;
+                        data += `<span class='fas fa-info-circle icon-blue float-right' title='{% trans "Pack Quantity" %}: ${row.pack_quantity} - {% trans "Total Quantity" %}: ${total}'></span>`;
-                        data += `<span class='fas fa-info-circle icon-blue float-right' title='{% trans "Pack Quantity" %}: ${pack_size} - {% trans "Total Quantity" %}: ${total}'></span>`;
                     }
 
                     return data;
@@ -2038,6 +2036,12 @@ function loadPartTable(table, url, options={}) {
         }
     });
 
+    columns.push({
+        field: 'units',
+        title: '{% trans "Units" %}',
+        sortable: true,
+    });
+
     columns.push({
         sortName: 'category',
         field: 'category_detail',

InvenTree/templates/js/translated/pricing.js

@@ -458,7 +458,7 @@ function loadPartSupplierPricingTable(options={}) {
             data = data.sort((a, b) => (a.quantity - b.quantity));
 
             var graphLabels = Array.from(data, (x) => (`${x.part_detail.SKU} - {% trans "Quantity" %} ${x.quantity}`));
-            var graphValues = Array.from(data, (x) => (x.price / x.part_detail.pack_size));
+            var graphValues = Array.from(data, (x) => (x.price / x.part_detail.pack_quantity_native));
 
             if (chart) {
                 chart.destroy();
@@ -518,7 +518,7 @@ function loadPartSupplierPricingTable(options={}) {
                     }
 
                     // Convert to unit pricing
-                    var unit_price = row.price / row.part_detail.pack_size;
+                    var unit_price = row.price / row.part_detail.pack_quantity_native;
 
                     var html = formatCurrency(unit_price, {
                         currency: row.price_currency
@@ -811,9 +811,12 @@ function loadPurchasePriceHistoryTable(options={}) {
                         return '-';
                     }
 
-                    return formatCurrency(row.purchase_price / row.supplier_part_detail.pack_size, {
+                    return formatCurrency(
+                        row.purchase_price / row.supplier_part_detail.pack_quantity_native,
+                        {
                             currency: row.purchase_price_currency
-                    });
+                        }
+                    );
                 }
             },
         ]

InvenTree/templates/js/translated/purchase_order.js

@@ -229,8 +229,8 @@ function poLineItemFields(options={}) {
                 supplier: options.supplier,
             },
             onEdit: function(value, name, field, opts) {
-                // If the pack_size != 1, add a note to the field
+                // If the pack_quantity != 1, add a note to the field
-                var pack_size = 1;
+                var pack_quantity = 1;
                 var units = '';
                 var supplier_part_id = value;
                 var quantity = getFormFieldValue('quantity', {}, opts);
@@ -250,14 +250,14 @@ function poLineItemFields(options={}) {
                     {
                         success: function(response) {
                             // Extract information from the returned query
-                            pack_size = response.pack_size || 1;
+                            pack_quantity = response.pack_quantity_native || 1;
                             units = response.part_detail.units || '';
                         },
                     }
                 ).then(function() {
                     // Update pack size information
-                    if (pack_size != 1) {
+                    if (pack_quantity != 1) {
-                        var txt = `<span class='fas fa-info-circle icon-blue'></span> {% trans "Pack Quantity" %}: ${pack_size} ${units}`;
+                        var txt = `<span class='fas fa-info-circle icon-blue'></span> {% trans "Pack Quantity" %}: ${formatDecimal(pack_quantity)} ${units}`;
                         $(opts.modal).find('#hint_id_quantity').after(`<div class='form-info-message' id='info-pack-size'>${txt}</div>`);
                     }
                 }).then(function() {
@@ -766,7 +766,7 @@ function orderParts(parts_list, options) {
                 // Callback function when supplier part is changed
                 // This is used to update the "pack size" attribute
                 var onSupplierPartChanged = function(value, name, field, opts) {
-                    var pack_size = 1;
+                    var pack_quantity = 1;
                     var units = '';
 
                     $(opts.modal).find(`#info-pack-size-${pk}`).remove();
@@ -779,13 +779,13 @@ function orderParts(parts_list, options) {
                             },
                             {
                                 success: function(response) {
-                                    pack_size = response.pack_size || 1;
+                                    pack_quantity = response.pack_quantity_native || 1;
                                     units = response.part_detail.units || '';
                                 }
                             }
                         ).then(function() {
-                            if (pack_size != 1) {
+                            if (pack_quantity != 1) {
-                                var txt = `<span class='fas fa-info-circle icon-blue'></span> {% trans "Pack Quantity" %}: ${pack_size} ${units}`;
+                                var txt = `<span class='fas fa-info-circle icon-blue'></span> {% trans "Pack Quantity" %}: ${pack_quantity} ${units}`;
                                 $(opts.modal).find(`#id_quantity_${pk}`).after(`<div class='form-info-message' id='info-pack-size-${pk}'>${txt}</div>`);
                             }
                         });
@@ -1021,15 +1021,17 @@ function receivePurchaseOrderItems(order_id, line_items, options={}) {
         }
 
         var units = line_item.part_detail.units || '';
-        var pack_size = line_item.supplier_part_detail.pack_size || 1;
+        let pack_quantity = line_item.supplier_part_detail.pack_quantity;
-        var pack_size_div = '';
+        let native_pack_quantity = line_item.supplier_part_detail.pack_quantity_native || 1;
 
-        var received = quantity * pack_size;
+        let pack_size_div = '';
 
-        if (pack_size != 1) {
+        var received = quantity * native_pack_quantity;
+
+        if (native_pack_quantity != 1) {
             pack_size_div = `
             <div class='alert alert-small alert-block alert-info'>
-                {% trans "Pack Quantity" %}: ${pack_size} ${units}<br>
+                {% trans "Pack Quantity" %}: ${formatDecimal(pack_quantity)}<br>
                 {% trans "Received Quantity" %}: <span class='pack_received_quantity' id='items_received_quantity_${pk}'>${received}</span> ${units}
             </div>`;
         }
@@ -1304,13 +1306,13 @@ function receivePurchaseOrderItems(order_id, line_items, options={}) {
                 );
 
                 // Add change callback for quantity field
-                if (item.supplier_part_detail.pack_size != 1) {
+                if (item.supplier_part_detail.pack_quantity_native != 1) {
                     $(opts.modal).find(`#id_items_quantity_${pk}`).change(function() {
                         var value = $(opts.modal).find(`#id_items_quantity_${pk}`).val();
 
                         var el = $(opts.modal).find(`#quantity_${pk}`).find('.pack_received_quantity');
 
-                        var actual = value * item.supplier_part_detail.pack_size;
+                        var actual = value * item.supplier_part_detail.pack_quantity_native;
                         actual = formatDecimal(actual);
                         el.text(actual);
                     });
@@ -2005,10 +2007,10 @@ function loadPurchaseOrderLineItemTable(table, options={}) {
 
                     let data = value;
 
-                    if (row.supplier_part_detail && row.supplier_part_detail.pack_size != 1.0) {
+                    if (row.supplier_part_detail && row.supplier_part_detail.pack_quantity_native != 1.0) {
-                        var pack_size = row.supplier_part_detail.pack_size;
+                        let pack_quantity = row.supplier_part_detail.pack_quantity;
-                        var total = value * pack_size;
+                        let total = value * row.supplier_part_detail.pack_quantity_native;
-                        data += `<span class='fas fa-info-circle icon-blue float-right' title='{% trans "Pack Quantity" %}: ${pack_size}${units} - {% trans "Total Quantity" %}: ${total}${units}'></span>`;
+                        data += `<span class='fas fa-info-circle icon-blue float-right' title='{% trans "Pack Quantity" %}: ${pack_quantity} - {% trans "Total Quantity" %}: ${total}${units}'></span>`;
                     }
 
                     return data;
@@ -2024,7 +2026,7 @@ function loadPurchaseOrderLineItemTable(table, options={}) {
             {
                 sortable: false,
                 switchable: true,
-                field: 'supplier_part_detail.pack_size',
+                field: 'supplier_part_detail.pack_quantity',
                 title: '{% trans "Pack Quantity" %}',
                 formatter: function(value, row) {
                     var units = row.part_detail.units;

InvenTree/templates/js/translated/table_filters.js

@@ -626,6 +626,11 @@ function getPartTableFilters() {
             type: 'bool',
             title: '{% trans "Component" %}',
         },
+        has_units: {
+            type: 'bool',
+            title: '{% trans "Has Units" %}',
+            description: '{% trans "Part has defined units" %}',
+        },
         has_ipn: {
             type: 'bool',
             title: '{% trans "Has IPN" %}',

docs/docs/part/part.md

@@ -55,7 +55,19 @@ Trackable parts can be assigned batch numbers or serial numbers which uniquely i
 
 ### Purchaseable
 
-If a part is designated as *Purchaseable* it can be purchased from external suppliers. Setting this flag allows parts to be added to [purchase orders](../order/purchase_order.md).
+If a part is designated as *Purchaseable* it can be purchased from external suppliers. Setting this flag allows parts be linked to supplier parts and procured via purchase orders.
+
+#### Suppliers
+
+A [Supplier](../order/company.md#suppliers) is an external vendor who provides goods or services.
+
+#### Supplier Parts
+
+Purchaseable parts can be linked to [Supplier Parts](../order/company.md#supplier-parts). A supplier part represents an individual piece or unit that is procured from an external vendor.
+
+#### Purchase Orders
+
+A [Purchase Order](../order/purchase_order.md) allows parts to be ordered from an external supplier.
 
 ### Salable
 
@@ -65,6 +77,31 @@ If a part is designated as *Salable* it can be sold to external customers. Setti
 
 By default, all parts are *Active*. Marking a part as inactive means it is not available for many actions, but the part remains in the database. If a part becomes obsolete, it is recommended that it is marked as inactive, rather than deleting it from the database.
 
+## Units of Measure
+
+Each type of part can define a custom "unit of measure" which is a standardized unit which is used to track quantities for a particular part. By default, the "unit of measure" for each part is blank, which means that each part is tracked in dimensionless quantities of "pieces".
+
+### Physical Units
+
+It is possible to track parts using physical quantity values, such as *metres* or *litres*. For example, it would make sense to track a "wire" in units of "metres":
+
+{% with id="part_units", url="part/part_units.png", description="Parts units" %}
+{% include 'img.html' %}
+{% endwith %}
+
+### Supplier Part Units
+
+By default, units of measure for [supplier parts](../order/company.md#supplier-parts) are specified in the same unit as their base part. However, supplier part units can be changed to any unit *which is compatible with the base unit*.
+
+!!! info "Example: Supplier Part Units"
+    If the base part has a unit of `metres` then valid units for any supplier parts would include `feet`, `cm`, `inches` (etc)
+
+If an incompatible unit type is specified, an error will be displayed:
+
+{% with id="part_units_invalid", url="part/part_units_invalid.png", description="Invalid supplier part units" %}
+{% include 'img.html' %}
+{% endwith %}
+
 ## Part Images
 
 Each part can have an associated image, which is used for display purposes throughout the InvenTree interface. A prominent example is on the part detail page itself: