feat(migrations): Add in SafeDeleteModel migration operation

fixtures/safe_migrations_apps/bad_flow_delete_model_double_pending_app/migrations/0001_initial.py

@@ -0,0 +1,26 @@
+# Generated by Django 3.1 on 2019-09-22 21:47
+
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="TestTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+            ],
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_model_double_pending_app/migrations/0002_delete_pending.py

@@ -0,0 +1,17 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+
+    dependencies = [
+        ("bad_flow_delete_model_double_pending_app", "0001_initial"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.MOVE_TO_PENDING,
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_model_double_pending_app/migrations/0003_double_pending.py

@@ -0,0 +1,17 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+
+    dependencies = [
+        ("bad_flow_delete_model_double_pending_app", "0002_delete_pending"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.MOVE_TO_PENDING,
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_model_double_pending_app/models.py

@@ -0,0 +1,5 @@
+from django.db import models
+
+
+class TestTable(models.Model):
+    field = models.IntegerField(default=0, null=False)

fixtures/safe_migrations_apps/bad_flow_delete_model_without_pending_app/migrations/0001_initial.py

@@ -0,0 +1,26 @@
+# Generated by Django 3.1 on 2019-09-22 21:47
+
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="TestTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+            ],
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_model_without_pending_app/migrations/0002_delete_without_pending.py

@@ -0,0 +1,17 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+
+    dependencies = [
+        ("bad_flow_delete_model_without_pending_app", "0001_initial"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.DELETE,
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_model_without_pending_app/models.py

@@ -0,0 +1,5 @@
+from django.db import models
+
+
+class TestTable(models.Model):
+    field = models.IntegerField(default=0, null=False)

fixtures/safe_migrations_apps/bad_flow_delete_pending_with_fk_constraints_app/migrations/0001_initial.py

@@ -0,0 +1,45 @@
+import django
+from django.db import migrations, models
+
+import sentry
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="FkTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+            ],
+        ),
+        migrations.CreateModel(
+            name="TestTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+                (
+                    "fk_table",
+                    sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="bad_flow_delete_pending_with_fk_constraints_app.fktable",
+                        db_index=False,
+                    ),
+                ),
+            ],
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_pending_with_fk_constraints_app/migrations/0002_delete_without_pending.py

@@ -0,0 +1,18 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+    atomic = False
+
+    dependencies = [
+        ("bad_flow_delete_pending_with_fk_constraints_app", "0001_initial"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.MOVE_TO_PENDING,
+        ),
+    ]

fixtures/safe_migrations_apps/bad_flow_delete_pending_with_fk_constraints_app/models.py

@@ -0,0 +1,12 @@
+from django.db import models
+
+from sentry.db.models import FlexibleForeignKey
+
+
+class FkTable(models.Model):
+    field = models.IntegerField(default=0, null=False)
+
+
+class TestTable(models.Model):
+    field = models.IntegerField(default=0, null=False)
+    fk_table = FlexibleForeignKey(FkTable, db_index=False)

fixtures/safe_migrations_apps/good_flow_delete_pending_with_fk_constraints_app/migrations/0001_initial.py

@@ -0,0 +1,46 @@
+# Generated by Django 3.1 on 2019-09-22 21:47
+import django
+from django.db import migrations, models
+
+import sentry
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="FkTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+            ],
+        ),
+        migrations.CreateModel(
+            name="TestTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+                (
+                    "fk_table",
+                    sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="good_flow_delete_pending_with_fk_constraints_app.fktable",
+                        db_index=False,
+                    ),
+                ),
+            ],
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_pending_with_fk_constraints_app/migrations/0002_remove_constraints_and_pending.py

@@ -0,0 +1,32 @@
+import django
+from django.db import migrations
+
+import sentry
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+    atomic = False
+
+    dependencies = [
+        ("good_flow_delete_pending_with_fk_constraints_app", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="TestTable",
+            name="fk_table",
+            field=sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                on_delete=django.db.models.deletion.CASCADE,
+                to="good_flow_delete_pending_with_fk_constraints_app.fktable",
+                db_index=False,
+                db_constraint=False,
+            ),
+        ),
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.MOVE_TO_PENDING,
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_pending_with_fk_constraints_app/migrations/0003_delete.py

@@ -0,0 +1,16 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+    dependencies = [
+        ("good_flow_delete_pending_with_fk_constraints_app", "0002_remove_constraints_and_pending"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.DELETE,
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_pending_with_fk_constraints_app/models.py

@@ -0,0 +1,12 @@
+from django.db import models
+
+from sentry.db.models import FlexibleForeignKey
+
+
+class FkTable(models.Model):
+    field = models.IntegerField(default=0, null=False)
+
+
+class TestTable(models.Model):
+    field = models.IntegerField(default=0, null=False)
+    fk_table = FlexibleForeignKey(FkTable, db_index=False)

fixtures/safe_migrations_apps/good_flow_delete_simple_app/migrations/0001_initial.py

@@ -0,0 +1,22 @@
+from django.db import migrations, models
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    initial = True
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name="TestTable",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+            ],
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_simple_app/migrations/0002_set_pending.py

@@ -0,0 +1,16 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+    dependencies = [
+        ("good_flow_delete_simple_app", "0001_initial"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.MOVE_TO_PENDING,
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_simple_app/migrations/0003_delete.py

@@ -0,0 +1,16 @@
+from sentry.new_migrations.migrations import CheckedMigration
+from sentry.new_migrations.monkey.models import SafeDeleteModel
+from sentry.new_migrations.monkey.state import DeletionAction
+
+
+class Migration(CheckedMigration):
+    dependencies = [
+        ("good_flow_delete_simple_app", "0002_set_pending"),
+    ]
+
+    operations = [
+        SafeDeleteModel(
+            name="TestTable",
+            deletion_action=DeletionAction.DELETE,
+        ),
+    ]

fixtures/safe_migrations_apps/good_flow_delete_simple_app/models.py

@@ -0,0 +1,5 @@
+from django.db import models
+
+
+class TestTable(models.Model):
+    field = models.IntegerField(default=0, null=False)

src/sentry/db/postgres/schema.py

@@ -88,14 +88,16 @@ def alter_db_table(self, model, old_db_table, new_db_table):
             "More info here: https://develop.sentry.dev/database-migrations/#renaming-tables"
         )
 
-    def delete_model(self, model):
+    def delete_model(self, model, is_safe=False):
         """
         It's never safe to delete a model using the standard migration process
         """
-        raise UnsafeOperationException(
-            f"Deleting the {model.__name__} model is unsafe.\n"
-            "More info here: https://develop.sentry.dev/database-migrations/#deleting-tables"
-        )
+        if not is_safe:
+            raise UnsafeOperationException(
+                f"Deleting the {model.__name__} model is unsafe.\n"
+                "More info here: https://develop.sentry.dev/database-migrations/#deleting-tables"
+            )
+        super(DatabaseSchemaEditorMixin, self).delete_model(model)
 
     def remove_field(self, model, field):
         """