Raise exception if downgrade can't proceed due to no ab_user table

.github/actions/migration_tests/action.yml

@@ -25,11 +25,12 @@ runs:
       shell: bash
       run: |
         breeze shell "${{ env.AIRFLOW_2_CMD }}" --use-airflow-version 2.10.5 --answer y &&
-        breeze shell "${{ env.AIRFLOW_3_CMD }}" --no-db-cleanup
+        breeze shell "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${{env.DB_MANGERS}}
+                    ${{ env.AIRFLOW_3_CMD }}" --no-db-cleanup
       env:
         COMPOSE_PROJECT_NAME: "docker-compose"
-        AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
         DB_RESET: "false"
+        DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
         AIRFLOW_2_CMD: >-
           airflow db reset --skip-init -y &&
           airflow db migrate --to-revision heads
@@ -47,11 +48,12 @@ runs:
       shell: bash
       run: >
         breeze shell "${{ env.AIRFLOW_2_CMD }}" --use-airflow-version 2.10.5 --answer y &&
-        breeze shell "${{ env.AIRFLOW_3_CMD }}" --no-db-cleanup
+        breeze shell "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${{env.DB_MANGERS}}
+             ${{ env.AIRFLOW_3_CMD }}" --no-db-cleanup
       env:
         COMPOSE_PROJECT_NAME: "docker-compose"
-        AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
         DB_RESET: "false"
+        DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
         AIRFLOW_2_CMD: >-
           airflow db reset -y
         AIRFLOW_3_CMD: >-
@@ -67,13 +69,14 @@ runs:
     - name: "Test ORM migration ${{env.BACKEND}}"
       shell: bash
       run: >
-        breeze shell "airflow db reset -y &&
+        breeze shell "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${{env.DB_MANAGERS}} &&
+        airflow db reset -y &&
         airflow db migrate --to-revision heads &&
         airflow db downgrade -n 2.7.0 -y &&
         airflow db migrate"
       env:
         COMPOSE_PROJECT_NAME: "docker-compose"
-        AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
+        DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
     - name: "Bring compose down again"
       shell: bash
       run: breeze down
@@ -82,12 +85,14 @@ runs:
     - name: "Test offline migration ${{env.BACKEND}}"
       shell: bash
       run: >
-        breeze shell "airflow db reset -y &&
+        breeze shell
+        "export AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS=${{env.DB_MANAGERS}} &&
+        airflow db reset -y &&
         airflow db downgrade -n 2.7.0 -y &&
         airflow db migrate -s"
       env:
         COMPOSE_PROJECT_NAME: "docker-compose"
-        AIRFLOW__DATABASE__EXTERNAL_DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
+        DB_MANAGERS: "airflow.providers.fab.auth_manager.models.db.FABDBManager"
       if: env.BACKEND != 'sqlite'
     - name: "Bring any containers left down"
       shell: bash

airflow-core/docs/img/airflow_erd.sha256

@@ -1 +1 @@
-1b5221fa589cfc8652242b95f24d218c632168238933b82b533321a217c2447f
+066cb891884eea1ee0496b5c507d4a52c20d0440387f9ec8bacb1d616a26e40e

airflow-core/src/airflow/migrations/versions/0042_3_0_0_add_uuid_primary_key_to_task_instance_.py

@@ -223,7 +223,9 @@ def upgrade():
                     """
                 ).bindparams(batch_size=batch_size)
             )
-            row_count = result.rowcount
+            row_count = 0
+            if result:
+                row_count = result.rowcount
             if row_count == 0:
                 break
             print(f"Migrated {row_count} task_instance rows in this batch...")

airflow-core/src/airflow/utils/db.py

@@ -1219,21 +1219,21 @@ def downgrade(*, to_revision, from_revision=None, show_sql_only=False, session:
     config = _get_alembic_config()
     # Check if downgrade is less than 3.0.0 and requires that `ab_user` fab table is present
     if _revision_greater(config, _REVISION_HEADS_MAP["3.0.0"], to_revision):
-        if conf.getboolean("core", "unit_test_mode"):
+        unitest_mode = conf.getboolean("core", "unit_test_mode")
+        if unitest_mode:
             try:
                 from airflow.providers.fab.auth_manager.models.db import FABDBManager
 
                 dbm = FABDBManager(session)
                 dbm.initdb()
             except ImportError:
                 log.warning("Import error occurred while importing FABDBManager. Skipping the check.")
-                pass
-        if not inspect(settings.engine).has_table("ab_user"):
-            log.error(
+                return
+        if not inspect(settings.engine).has_table("ab_user") and not unitest_mode:
+            raise AirflowException(
                 "Downgrade to revision less than 3.0.0 requires that `ab_user` table is present. "
                 "Please add FabDBManager to [core] external_db_managers and run fab migrations before proceeding"
             )
-            return
     with create_global_lock(session=session, lock=DBLocks.MIGRATIONS):
         if show_sql_only:
             log.warning("Generating sql scripts for manual migration.")