fix: Avoid a long table lock for the first_name migration

api/tests/unit/users/test_migrations.py

@@ -0,0 +1,53 @@
+import pytest
+from django.conf import settings
+from django_test_migrations.migrator import Migrator
+
+pytestmark = pytest.mark.skipif(
+    settings.SKIP_MIGRATION_TESTS is True,
+    reason="Skip migration tests to speed up tests where necessary",
+)
+
+
+def test_0039_ffadminuser_first_name_v2__values_expected(migrator: Migrator) -> None:
+    # Given
+    old_state = migrator.apply_initial_migration(
+        ("users", "0038_create_hubspot_tracker")
+    )
+    OldFFAdminUser = old_state.apps.get_model("users", "FFAdminUser")
+
+    user = OldFFAdminUser.objects.create(first_name="Testfirstname")
+
+    # When
+    new_state = migrator.apply_tested_migration(
+        ("users", "0039_ffadminuser_first_name_v2")
+    )
+    NewFFAdminUser = new_state.apps.get_model("users", "FFAdminUser")
+
+    # Then
+    assert NewFFAdminUser.objects.get(id=user.id).first_name == user.first_name
+
+
+def test_0039_ffadminuser_first_name_v2__reverse__values_expected(
+    migrator: Migrator,
+) -> None:
+    # Given
+    old_state = migrator.apply_initial_migration(
+        ("users", "0039_ffadminuser_first_name_v2")
+    )
+    NewFFAdminUser = old_state.apps.get_model("users", "FFAdminUser")
+
+    user = NewFFAdminUser.objects.create(
+        first_name="TestfirstnameTestfirstnameTestfirstnameTestfirstname"
+    )
+
+    # When
+    new_state = migrator.apply_tested_migration(
+        ("users", "0038_create_hubspot_tracker")
+    )
+    OldFFAdminUser = new_state.apps.get_model("users", "FFAdminUser")
+
+    # Then
+    assert (
+        OldFFAdminUser.objects.get(id=user.id).first_name
+        == "TestfirstnameTestfirstnameTest"
+    )

api/users/migrations/0039_ffadminuser_first_name_v2.py

@@ -0,0 +1,55 @@
+# Generated by Django 4.2.16 on 2024-11-05 10:49
+
+from pathlib import Path
+from django.db import migrations, models
+
+
+def _get_ffadminuser_table_name() -> str:
+    from users.models import FFAdminUser
+
+    return FFAdminUser._meta.db_table
+
+
+_ffadminuser_table_name = _get_ffadminuser_table_name()
+
+
+parent_dir = Path(__file__).parent.resolve()
+
+with open(parent_dir / "sql/0039_ffadminuser_first_name_v2.sql") as f:
+    sql_forwards = f.read().format(ffadminuser_table_name=_ffadminuser_table_name)
+
+with open(parent_dir / "sql/0039_ffadminuser_first_name_v2_reverse.sql") as f:
+    sql_reverse = f.read().format(ffadminuser_table_name=_ffadminuser_table_name)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("users", "0038_create_hubspot_tracker"),
+    ]
+
+    operations = [
+        migrations.SeparateDatabaseAndState(
+            state_operations=[
+                migrations.RemoveField(
+                    model_name="ffadminuser",
+                    name="first_name",
+                ),
+                migrations.AddField(
+                    model_name="ffadminuser",
+                    name="first_name",
+                    field=models.CharField(
+                        db_column="first_name_v2",
+                        max_length=150,
+                        verbose_name="first name",
+                    ),
+                ),
+            ],
+            database_operations=[
+                migrations.RunSQL(
+                    sql=sql_forwards,
+                    reverse_sql=sql_reverse,
+                )
+            ],
+        )
+    ]

api/users/migrations/sql/0039_ffadminuser_first_name_v2.sql

@@ -0,0 +1,8 @@
+ALTER TABLE {ffadminuser_table_name}
+ADD COLUMN first_name_v2 varchar(150) NULL;
+UPDATE {ffadminuser_table_name}
+SET first_name_v2 = {ffadminuser_table_name}.first_name;
+ALTER TABLE {ffadminuser_table_name}
+ALTER COLUMN first_name_v2 SET NOT NULL;
+ALTER TABLE {ffadminuser_table_name}
+DROP COLUMN first_name;

api/users/migrations/sql/0039_ffadminuser_first_name_v2_reverse.sql

@@ -0,0 +1,8 @@
+ALTER TABLE {ffadminuser_table_name}
+ADD COLUMN first_name varchar(30) NULL;
+UPDATE {ffadminuser_table_name}
+SET first_name = left({ffadminuser_table_name}.first_name_v2, 30);
+ALTER TABLE {ffadminuser_table_name}
+ALTER COLUMN first_name SET NOT NULL;
+ALTER TABLE {ffadminuser_table_name}
+DROP COLUMN first_name_v2;

api/users/models.py

@@ -99,7 +99,11 @@ class FFAdminUser(LifecycleModel, AbstractUser):
     email = models.EmailField(unique=True, null=False)
     objects = UserManager()
     username = models.CharField(unique=True, max_length=150, null=True, blank=True)
-    first_name = models.CharField("first name", max_length=150)
+    first_name = models.CharField(
+        "first name",
+        max_length=150,
+        db_column="first_name_v2",
+    )
     last_name = models.CharField("last name", max_length=150)
     google_user_id = models.CharField(max_length=50, null=True, blank=True)
     github_user_id = models.CharField(max_length=50, null=True, blank=True)