Delete existing forecasts before running new breaking migrations

Author: erick-otenyo

forecastmanager/migrations/0013_alter_city_options_alter_forecast_unique_together_and_more.py

@@ -1,17 +1,25 @@
 # Generated by Django 4.2.3 on 2024-03-05 12:41
 
-from django.db import migrations, models
 import django.db.models.deletion
 import modelcluster.fields
+from django.db import migrations, models
 
 
-class Migration(migrations.Migration):
+def delete_existing_forecasts(apps, schema_editor):
+    model = apps.get_model('forecastmanager', 'forecast')
+    model.objects.all().delete()
 
+
+class Migration(migrations.Migration):
     dependencies = [
         ('forecastmanager', '0012_alter_forecastperiod_forecast_effective_time'),
     ]
 
     operations = [
+        migrations.RunPython(
+            delete_existing_forecasts,
+            migrations.RunPython.noop
+        ),
         migrations.AlterModelOptions(
             name='city',
             options={'ordering': ['name'], 'verbose_name': 'City', 'verbose_name_plural': 'Cities'},
@@ -28,7 +36,9 @@ class Migration(migrations.Migration):
                 ('symbol', models.CharField(max_length=100, verbose_name='Weather Symbol')),
                 ('label', models.CharField(max_length=100, unique=True, verbose_name='Label')),
                 ('alias', models.CharField(blank=True, max_length=100, null=True, unique=True, verbose_name='Alias')),
-                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE, related_name='weather_conditions', to='forecastmanager.forecastsetting')),
+                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE,
+                                                           related_name='weather_conditions',
+                                                           to='forecastmanager.forecastsetting')),
             ],
             options={
                 'ordering': ['sort_order'],
@@ -40,9 +50,13 @@ class Migration(migrations.Migration):
             fields=[
                 ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                 ('sort_order', models.IntegerField(blank=True, editable=False, null=True)),
-                ('city', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='forecastmanager.city', verbose_name='City')),
-                ('condition', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='forecastmanager.weathercondition')),
-                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE, related_name='city_forecasts', to='forecastmanager.forecast')),
+                ('city', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='forecastmanager.city',
+                                           verbose_name='City')),
+                ('condition', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE,
+                                                to='forecastmanager.weathercondition')),
+                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE,
+                                                           related_name='city_forecasts',
+                                                           to='forecastmanager.forecast')),
             ],
             options={
                 'unique_together': {('parent', 'city')},
@@ -66,8 +80,11 @@ class Migration(migrations.Migration):
                 ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                 ('sort_order', models.IntegerField(blank=True, editable=False, null=True)),
                 ('value', models.CharField(blank=True, max_length=255, null=True, verbose_name='Value')),
-                ('parameter', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='data_values', to='forecastmanager.forecastdataparameters')),
-                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE, related_name='data_values', to='forecastmanager.cityforecast')),
+                ('parameter', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='data_values',
+                                                to='forecastmanager.forecastdataparameters')),
+                ('parent', modelcluster.fields.ParentalKey(on_delete=django.db.models.deletion.CASCADE,
+                                                           related_name='data_values',
+                                                           to='forecastmanager.cityforecast')),
             ],
             options={
                 'unique_together': {('parent', 'parameter')},

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = forecastmanager
-version = 0.4.0
+version = 0.4.1
 description = Integration of Weather City Forecasts Manager in Wagtail Projects.
 long_description = file:README.md
 long_description_content_type = text/markdown