diff --git a/InvenTree/part/migrations/0112_auto_20230525_1606.py b/InvenTree/part/migrations/0112_auto_20230525_1606.py
index ff7d296336..43e7d2abf5 100644
--- a/InvenTree/part/migrations/0112_auto_20230525_1606.py
+++ b/InvenTree/part/migrations/0112_auto_20230525_1606.py
@@ -1,56 +1,96 @@
# Generated by Django 3.2.19 on 2023-05-31 12:05
-from django.core.exceptions import FieldDoesNotExist
+"""
+Note: This is a total hack method to delete columns (if they already exist).
+
+Due to an improper set of migrations merges,
+there may exist a situation where the columns (defined in the migrations below) already exist.
+
+In this case, we want to delete the columns, and then re-add them.
+
+Original error: https://github.com/inventree/InvenTree/pull/4898
+1st fix: https://github.com/inventree/InvenTree/pull/4961
+2nd fix: https://github.com/inventree/InvenTree/pull/4977
+3rd fix: https://github.com/inventree/InvenTree/pull/4987
+"""
+
from django.db import migrations, models
-def delete_columns(apps, schema_editor):
- """Hack method to delete columns (if they already exist).
+class RemoveFieldOrSkip(migrations.RemoveField):
+ """Custom RemoveField operation which will fail gracefully if the field does not exist
- Due to an improper set of migrations merges,
- there may exist a situation where the columns (defined in the migrations below) already exist.
-
- In this case, we want to delete the columns, and then re-add them.
-
- Original error: https://github.com/inventree/InvenTree/pull/4898
- Attempted fix: https://github.com/inventree/InvenTree/pull/4961
- This fix: https://github.com/inventree/InvenTree/pull/4977
+ Ref: https://stackoverflow.com/questions/58518726/how-to-ignore-a-specific-migration
"""
- PartParameterTemplate = apps.get_model('part', 'PartParameterTemplate')
+ def database_backwards(self, app_label, schema_editor, from_state, to_state) -> None:
+ # Backwards migration should not do anything
+ pass
- # Check if the 'checkbox' column exists
- try:
- print("Checking for column 'checkbox' in table 'part_partparametertemplate'")
- PartParameterTemplate._meta.get_field('checkbox')
- schema_editor.execute("ALTER TABLE part_partparametertemplate DROP COLUMN checkbox;")
- except (AttributeError, FieldDoesNotExist):
- print("Column 'checkbox' does not exist (skipping)")
+ def database_forwards(self, app_label, schema_editor, from_state, to_state) -> None:
+ """Forwards migration *attempts* to remove existing fields, but will fail gracefully if they do not exist"""
- try:
- print("Checking for column 'choices' in table 'part_partparametertemplate'")
- PartParameterTemplate._meta.get_field('choices')
- schema_editor.execute("ALTER TABLE part_partparametertemplate DROP COLUMN choices;")
- except (AttributeError, FieldDoesNotExist):
- print("Column 'choices' does not exist (skipping)")
+ try:
+ super().database_forwards(app_label, schema_editor, from_state, to_state)
+ print(f'Removed field {self.name} from model {self.model_name}')
+ except Exception as exc:
+ pass
+
+ def state_forwards(self, app_label, state) -> None:
+ try:
+ super().state_forwards(app_label, state)
+ except Exception:
+ pass
+
+class AddFieldOrSkip(migrations.AddField):
+ """Custom AddField operation which will fail gracefully if the field already exists
+
+ Ref: https://stackoverflow.com/questions/58518726/how-to-ignore-a-specific-migration
+ """
+
+ def database_backwards(self, app_label, schema_editor, from_state, to_state) -> None:
+ # Backwards migration should not do anything
+ pass
+
+ def database_forwards(self, app_label, schema_editor, from_state, to_state) -> None:
+ """Forwards migration *attempts* to remove existing fields, but will fail gracefully if they do not exist"""
+
+ try:
+ super().database_forwards(app_label, schema_editor, from_state, to_state)
+ print(f'Added field {self.name} to model {self.model_name}')
+ except Exception as exc:
+ pass
+
+ def state_forwards(self, app_label, state) -> None:
+ try:
+ super().state_forwards(app_label, state)
+ except Exception:
+ pass
class Migration(migrations.Migration):
+ atomic = False
+
dependencies = [
('part', '0111_auto_20230521_1350'),
]
operations = [
- migrations.RunPython(
- delete_columns, reverse_code=migrations.RunPython.noop
+ RemoveFieldOrSkip(
+ model_name='partparametertemplate',
+ name='checkbox',
),
- migrations.AddField(
+ RemoveFieldOrSkip(
+ model_name='partparametertemplate',
+ name='choices',
+ ),
+ AddFieldOrSkip(
model_name='partparametertemplate',
name='checkbox',
field=models.BooleanField(default=False, help_text='Is this parameter a checkbox?', verbose_name='Checkbox'),
),
- migrations.AddField(
+ AddFieldOrSkip(
model_name='partparametertemplate',
name='choices',
field=models.CharField(blank=True, help_text='Valid choices for this parameter (comma-separated)', max_length=5000, verbose_name='Choices'),
diff --git a/InvenTree/part/test_migrations.py b/InvenTree/part/test_migrations.py
index f2eed6f315..bd0e3aa173 100644
--- a/InvenTree/part/test_migrations.py
+++ b/InvenTree/part/test_migrations.py
@@ -189,3 +189,38 @@ class PartUnitsMigrationTest(MigratorTestCase):
self.assertEqual(part_2.units, 'inch')
self.assertEqual(part_3.units, '')
self.assertEqual(part_4.units, 'percent')
+
+
+class TestPartParameterTemplateMigration(MigratorTestCase):
+ """Test for data migration of PartParameterTemplate
+
+ Ref: https://github.com/inventree/InvenTree/pull/4987
+ """
+
+ migrate_from = ('part', '0110_alter_part_units')
+ migrate_to = ('part', '0113_auto_20230531_1205')
+
+ def prepare(self):
+ """Prepare some parts with units"""
+
+ PartParameterTemplate = self.old_state.apps.get_model('part', 'partparametertemplate')
+
+ # Create a test template
+ template = PartParameterTemplate.objects.create(name='Template 1', description='a part parameter template')
+
+ # Ensure that the 'choices' and 'checkbox' fields do not exist
+ with self.assertRaises(AttributeError):
+ template.choices
+
+ with self.assertRaises(AttributeError):
+ template.checkbox
+
+ def test_units_migration(self):
+ """Test that the new fields have been added correctly"""
+
+ PartParameterTemplate = self.new_state.apps.get_model('part', 'partparametertemplate')
+
+ template = PartParameterTemplate.objects.get(name='Template 1')
+
+ self.assertEqual(template.choices, '')
+ self.assertEqual(template.checkbox, False)