Refactor how form errors are handled

- When in doubt, refer to the django docs
- There was a *much* better way (thanks, form.add_error)!
- The anti-pattern was deleted, and lo, there was much rejoicing
- Some other refactoring too

InvenTree/stock/models.py

@@ -822,14 +822,11 @@ class StockItem(MPTTModel):
             raise ValidationError({"quantity": _("Quantity does not match serial numbers")})
 
         # Test if each of the serial numbers are valid
-        existing = []
-
-        for serial in serials:
-            if self.part.checkIfSerialNumberExists(serial):
-                existing.append(serial)
+        existing = self.part.find_conflicting_serial_numbers(serials)
 
         if len(existing) > 0:
-            raise ValidationError({"serial_numbers": _("Serial numbers already exist: ") + str(existing)})
+            exists = ','.join([str(x) for x in existing])
+            raise ValidationError({"serial_numbers": _("Serial numbers already exist") + ': ' + exists})
 
         # Create a new stock item for each unique serial number
         for serial in serials:

InvenTree/stock/tests.py

@@ -407,6 +407,13 @@ class VariantTest(StockTest):
 
         self.assertEqual(chair.getLatestSerialNumber(), '22')
 
+        # Check for conflicting serial numbers
+        to_check = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+        conflicts = chair.find_conflicting_serial_numbers(to_check)
+
+        self.assertEqual(len(conflicts), 6)
+
         # Same operations on a sub-item
         variant = Part.objects.get(pk=10003)
         self.assertEqual(variant.getLatestSerialNumber(), '22')

InvenTree/stock/views.py

@@ -417,8 +417,8 @@ class StockItemDeleteTestData(AjaxUpdateView):
         confirm = str2bool(request.POST.get('confirm', False))
 
         if confirm is not True:
-            form.errors['confirm'] = [_('Confirm test data deletion')]
-            form.non_field_errors = [_('Check the confirmation box')]
+            form.add_error('confirm', _('Confirm test data deletion'))
+            form.add_error(None, _('Check the confirmation box'))
         else:
             stock_item.test_results.all().delete()
             valid = True
@@ -918,7 +918,7 @@ class StockItemUninstall(AjaxView, FormMixin):
 
         if not confirmed:
             valid = False
-            form.errors['confirm'] = [_('Confirm stock adjustment')]
+            form.add_error('confirm', _('Confirm stock adjustment'))
 
         data = {
             'form_valid': valid,
@@ -1116,7 +1116,7 @@ class StockAdjust(AjaxView, FormMixin):
 
         if not confirmed:
             valid = False
-            form.errors['confirm'] = [_('Confirm stock adjustment')]
+            form.add_error('confirm', _('Confirm stock adjustment'))
 
         data = {
             'form_valid': valid,
@@ -1416,7 +1416,7 @@ class StockItemSerialize(AjaxUpdateView):
         try:
             numbers = ExtractSerialNumbers(serials, quantity)
         except ValidationError as e:
-            form.errors['serial_numbers'] = e.messages
+            form.add_error('serial_numbers', e.messages)
             valid = False
             numbers = []
         
@@ -1428,9 +1428,9 @@ class StockItemSerialize(AjaxUpdateView):
                 
                 for k in messages.keys():
                     if k in ['quantity', 'destination', 'serial_numbers']:
-                        form.errors[k] = messages[k]
+                        form.add_error(k, messages[k])
                     else:
-                        form.non_field_errors = [messages[k]]
+                        form.add_error(None, messages[k])
 
                 valid = False
 
@@ -1621,14 +1621,14 @@ class StockItemCreate(AjaxCreateView):
                 part = None
                 quantity = 1
                 valid = False
-                form.errors['quantity'] = [_('Invalid quantity')]
+                form.add_error('quantity', _('Invalid quantity'))
 
             if quantity < 0:
-                form.errors['quantity'] = [_('Quantity cannot be less than zero')]
+                form.add_error('quantity', _('Quantity cannot be less than zero'))
                 valid = False
 
             if part is None:
-                form.errors['part'] = [_('Invalid part selection')]
+                form.add_error('part', _('Invalid part selection'))
             else:
                 # A trackable part must provide serial numbesr
                 if part.trackable:
@@ -1641,15 +1641,14 @@ class StockItemCreate(AjaxCreateView):
                         try:
                             serials = ExtractSerialNumbers(sn, quantity)
 
-                            existing = []
-
-                            for serial in serials:
-                                if part.checkIfSerialNumberExists(serial):
-                                    existing.append(serial)
+                            existing = part.find_conflicting_serial_numbers(serial)
 
                             if len(existing) > 0:
                                 exists = ",".join([str(x) for x in existing])
-                                form.errors['serial_numbers'] = [_('The following serial numbers already exist: ({sn})'.format(sn=exists))]
+                                form.add_error(
+                                    'serial_numbers',
+                                    _('Serial numbers already exist') + ': ' + exists
+                                )
                                 valid = False
 
                             else:
@@ -1681,7 +1680,7 @@ class StockItemCreate(AjaxCreateView):
                                     valid = True
 
                         except ValidationError as e:
-                            form.errors['serial_numbers'] = e.messages
+                            form.add_error('serial_numbers', e.messages)
                             valid = False
 
                     else: