don't use branch on ci

.github/workflows/ci-backend.yml

@@ -173,7 +173,7 @@ jobs:
         if: needs.changes.outputs.backend == 'true'
         timeout-minutes: 10
 
-        name: Validate Django migrations
+        name: Validate Django and CH migrations
         runs-on: depot-ubuntu-latest-4
 
         steps:
@@ -231,6 +231,9 @@ jobs:
                   # initial migrations (0001_*) as these are guaranteed to be
                   # run on initial setup where there is no data.
                   git diff --name-status origin/master..HEAD | grep "A\sposthog/migrations/" | awk '{print $2}' | grep -v migrations/0001_ | python manage.py test_migrations_are_safe
+
+            - name: Check CH migrations
+              run: |
                   # Same as above, except now for CH looking at files that were added in posthog/clickhouse/migrations/
                   git diff --name-status origin/master..HEAD | grep "A\sposthog/clickhouse/migrations/" | awk '{print $2}' |  python manage.py test_ch_migrations_are_safe
 

posthog/management/commands/test_ch_migrations_are_safe.py

@@ -11,7 +11,7 @@
 logger = logging.getLogger(__name__)
 repo_path = os.getcwd()
 repo = Repo(repo_path)
-current_branch = repo.active_branch.name
+current_sha = repo.head.object.hexsha
 
 
 class Command(BaseCommand):
@@ -22,7 +22,7 @@ def run_and_check_migration(new_migration):
             repo.git.checkout("master")
             old_migration_files = os.listdir("posthog/clickhouse/migrations")
             old_migrations = []
-            repo.git.checkout(current_branch)
+            repo.git.checkout(current_sha)
 
             for migration in old_migration_files:
                 match = re.findall(r"([0-9]+)_([a-zA-Z_0-9]+)\.py", migration)