[AIRFLOW-6860] Default ignore_first_depends_on_past to True (#7490)

UPDATING.md

@@ -61,6 +61,11 @@ https://developers.google.com/style/inclusive-documentation
 
 -->
 
+### Deprecating ignore_first_depends_on_past on backfill command and default it to True
+
+When doing backfill with `depends_on_past` dags, users will need to pass `ignore_first_depends_on_past`.
+We should default it as `true` to avoid confusion
+
 ### Custom executors is loaded using full import path
 
 In previous versions of Airflow it was possible to use plugins to load custom executors. It is still

airflow/cli/commands/dag_command.py

@@ -67,6 +67,13 @@ def dag_backfill(args, dag=None):
 
     signal.signal(signal.SIGTERM, sigint_handler)
 
+    import warnings
+    warnings.warn('--ignore_first_depends_on_past is deprecated as the value is always set to True',
+                  category=PendingDeprecationWarning)
+
+    if args.ignore_first_depends_on_past is False:
+        args.ignore_first_depends_on_past = True
+
     dag = dag or get_dag(args.subdir, args.dag_id)
 
     if not args.start_date and not args.end_date:

airflow/models/baseoperator.py

@@ -1010,7 +1010,7 @@ class BaseOperator(Operator, LoggingMixin):
             self,
             start_date: Optional[datetime] = None,
             end_date: Optional[datetime] = None,
-            ignore_first_depends_on_past: bool = False,
+            ignore_first_depends_on_past: bool = True,
             ignore_ti_state: bool = False,
             mark_success: bool = False) -> None:
         """

airflow/models/dag.py

@@ -1331,7 +1331,7 @@ class DAG(BaseDag, LoggingMixin):
             executor=None,
             donot_pickle=conf.getboolean('core', 'donot_pickle'),
             ignore_task_deps=False,
-            ignore_first_depends_on_past=False,
+            ignore_first_depends_on_past=True,
             pool=None,
             delay_on_limit_secs=1.0,
             verbose=False,

tests/cli/commands/test_dag_command.py

@@ -72,7 +72,7 @@ class TestCliDags(unittest.TestCase):
             conf=None,
             delay_on_limit_secs=1.0,
             donot_pickle=False,
-            ignore_first_depends_on_past=False,
+            ignore_first_depends_on_past=True,
             ignore_task_deps=False,
             local=False,
             mark_success=False,
@@ -111,7 +111,7 @@ class TestCliDags(unittest.TestCase):
             conf=None,
             delay_on_limit_secs=1.0,
             donot_pickle=False,
-            ignore_first_depends_on_past=False,
+            ignore_first_depends_on_past=True,
             ignore_task_deps=False,
             local=True,
             mark_success=False,

tests/models/test_taskinstance.py

@@ -785,7 +785,7 @@ class TestTaskInstance(unittest.TestCase):
         ti = TI(task, run_date)
 
         # depends_on_past prevents the run
-        task.run(start_date=run_date, end_date=run_date)
+        task.run(start_date=run_date, end_date=run_date, ignore_first_depends_on_past=False)
         ti.refresh_from_db()
         self.assertIs(ti.state, None)