Adds 'consumable' field to BomItem model (#2890)

* Adds 'consumable' field to BomItem model

* Add consumable field to API

* Consumable items always count as "allocated" for a build

* Add new BOM fields to BOM item checksum calculation

* Display 'consumable' status in BOM table

* Fix order of database migrations

* Update unit tests

* Fix for BOM table

* Remove "infinite" field from StockItem model

- Not used anywhere for functionality
- Hidden from the user
- Now replaced by the "consumable" concept in the BuildOrder model

* Update build order allocation table display

* Prevent auto-allocation of stock to consumable BOM items

* Ignore consumable BOM items when allocating stock to a build order

* Reimplmement "footer" row for BOM table

* Fix "can_build" calculation

- Ignore "consumable" BOM items

* Unrelated typo fix

* Tweak BOM table

* More visual tweaks to BOM table

* Add unit test for consumable field

InvenTree/part/models.py

@@ -1134,7 +1134,12 @@ class Part(InvenTreeBarcodeMixin, MetadataMixin, MPTTModel):
         total = None
 
         # Prefetch related tables, to reduce query expense
-        queryset = self.get_bom_items().prefetch_related(
+        queryset = self.get_bom_items()
+
+        # Ignore 'consumable' BOM items for this calculation
+        queryset = queryset.filter(consumable=False)
+
+        queryset = queryset.prefetch_related(
             'sub_part__stock_items',
             'sub_part__stock_items__allocations',
             'sub_part__stock_items__sales_order_allocations',
@@ -2526,6 +2531,7 @@ class BomItem(DataImportMixin, models.Model):
         sub_part: Link to the child part (the part that will be consumed)
         quantity: Number of 'sub_parts' consumed to produce one 'part'
         optional: Boolean field describing if this BomItem is optional
+        consumable: Boolean field describing if this BomItem is considered a 'consumable'
         reference: BOM reference field (e.g. part designators)
         overage: Estimated losses for a Build. Can be expressed as absolute value (e.g. '7') or a percentage (e.g. '2%')
         note: Note field for this BOM item
@@ -2544,6 +2550,7 @@ class BomItem(DataImportMixin, models.Model):
         'allow_variants': {},
         'inherited': {},
         'optional': {},
+        'consumable': {},
         'note': {},
         'part': {
             'label': _('Part'),
@@ -2649,7 +2656,17 @@ class BomItem(DataImportMixin, models.Model):
     # Quantity required
     quantity = models.DecimalField(default=1.0, max_digits=15, decimal_places=5, validators=[MinValueValidator(0)], verbose_name=_('Quantity'), help_text=_('BOM quantity for this BOM item'))
 
-    optional = models.BooleanField(default=False, verbose_name=_('Optional'), help_text=_("This BOM item is optional"))
+    optional = models.BooleanField(
+        default=False,
+        verbose_name=_('Optional'),
+        help_text=_("This BOM item is optional")
+    )
+
+    consumable = models.BooleanField(
+        default=False,
+        verbose_name=_('Consumable'),
+        help_text=_("This BOM item is consumable (it is not tracked in build orders)")
+    )
 
     overage = models.CharField(max_length=24, blank=True, validators=[validators.validate_overage],
                                verbose_name=_('Overage'),
@@ -2698,6 +2715,14 @@ class BomItem(DataImportMixin, models.Model):
         result_hash.update(str(self.optional).encode())
         result_hash.update(str(self.inherited).encode())
 
+        # Optionally encoded for backwards compatibility
+        if self.consumable:
+            result_hash.update(str(self.consumable).encode())
+
+        # Optionally encoded for backwards compatibility
+        if self.allow_variants:
+            result_hash.update(str(self.allow_variants).encode())
+
         return str(result_hash.digest())
 
     def validate_hash(self, valid=True):