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new f089b5b2e93 Fix trigger template rendering failure when operator
template_fields differ from trigger attributes (#64715)
f089b5b2e93 is described below
commit f089b5b2e93f3a63a788975a63d66b5d8bb7dd50
Author: David Blain <[email protected]>
AuthorDate: Thu Apr 9 09:14:00 2026 +0200
Fix trigger template rendering failure when operator template_fields differ
from trigger attributes (#64715)
Fix trigger template rendering failure when operator template_fields differ
from trigger attributes (#64715)
---
airflow-core/src/airflow/triggers/base.py | 23 ++++++-
.../tests/unit/triggers/test_base_trigger.py | 71 ++++++++++++++++++++++
2 files changed, 92 insertions(+), 2 deletions(-)
diff --git a/airflow-core/src/airflow/triggers/base.py
b/airflow-core/src/airflow/triggers/base.py
index 7ca7ed20a74..205e830c365 100644
--- a/airflow-core/src/airflow/triggers/base.py
+++ b/airflow-core/src/airflow/triggers/base.py
@@ -109,8 +109,26 @@ class BaseTrigger(abc.ABC, Templater, LoggingMixin):
if self.task_instance:
self.task_id = self.task_instance.task_id
if self.task:
- self.template_fields = self.task.template_fields
self.template_ext = self.task.template_ext
+ # Only keep operator template_fields that are also keys in
+ # start_trigger_args.trigger_kwargs *and* exist on the trigger.
+ # Using the full operator template_fields would cause
+ # AttributeError when the trigger does not have attributes with
+ # the same names as the operator (e.g. "bash_command").
+ #
+ # When start_trigger_args is None (normal defer path), the
triggerer
+ # does not build a template context, so render_template_fields is
+ # never called and empty template_fields is safe.
+ start_trigger_args = getattr(self.task, "start_trigger_args", None)
+ trigger_kwarg_keys = (
+ set((start_trigger_args.trigger_kwargs or {}).keys()) if
start_trigger_args else set()
+ )
+ if trigger_kwarg_keys:
+ self.template_fields = tuple(
+ f for f in self.task.template_fields if f in
trigger_kwarg_keys and hasattr(self, f)
+ )
+ else:
+ self.template_fields = ()
def render_template_fields(
self,
@@ -127,7 +145,8 @@ class BaseTrigger(abc.ABC, Templater, LoggingMixin):
"""
if not jinja_env:
jinja_env = self.get_template_env()
- # We only need to render templated fields if templated fields are part
of the start_trigger_args
+ # self.template_fields is already filtered (in the task_instance
setter) to only
+ # include fields present in start_trigger_args.trigger_kwargs and on
this trigger.
self._do_render_template_fields(self, self.template_fields, context,
jinja_env, set())
@abc.abstractmethod
diff --git a/airflow-core/tests/unit/triggers/test_base_trigger.py
b/airflow-core/tests/unit/triggers/test_base_trigger.py
index 53066c46f6a..d9e38385a20 100644
--- a/airflow-core/tests/unit/triggers/test_base_trigger.py
+++ b/airflow-core/tests/unit/triggers/test_base_trigger.py
@@ -27,6 +27,18 @@ class DummyOperator(BaseOperator):
template_fields = ("name",)
+class OperatorWithExtraTemplateFields(BaseOperator):
+ """Operator whose template_fields do NOT all exist on the trigger."""
+
+ template_fields = ("bash_command", "env", "name")
+
+ def __init__(self, bash_command="", env=None, name="", **kwargs):
+ super().__init__(**kwargs)
+ self.bash_command = bash_command
+ self.env = env
+ self.name = name
+
+
class DummyTrigger(BaseTrigger):
def __init__(self, name: str, **kwargs):
super().__init__(**kwargs)
@@ -67,3 +79,62 @@ def test_render_template_fields(create_task_instance):
trigger.render_template_fields(context={"name": "world"})
assert trigger.name == "Hello world"
+
+
[email protected]_test
+def
test_render_template_fields_filters_to_trigger_kwargs(create_task_instance):
+ """Only fields present in both trigger_kwargs and on the trigger should be
rendered.
+
+ Operator template_fields like 'bash_command' and 'env' that don't exist on
the
+ trigger must be excluded to avoid AttributeError.
+ """
+ op = OperatorWithExtraTemplateFields(
+ task_id="extra_fields_task",
+ bash_command="echo hello",
+ env={"KEY": "val"},
+ name="static",
+ )
+ ti = create_task_instance(
+ task=op,
+ start_from_trigger=True,
+ start_trigger_args=StartTriggerArgs(
+
trigger_cls=f"{DummyTrigger.__module__}.{DummyTrigger.__qualname__}",
+ next_method="resume_method",
+ trigger_kwargs={"name": "Hello {{ name }}"},
+ ),
+ )
+
+ trigger = DummyTrigger(name="Hello {{ name }}")
+ trigger.task_instance = ti
+
+ # Only 'name' should be in template_fields; 'bash_command' and 'env' are
excluded
+ # because they aren't keys in trigger_kwargs or don't exist on the trigger.
+ assert trigger.template_fields == ("name",)
+
+ # Rendering must not raise AttributeError for missing operator fields
+ trigger.render_template_fields(context={"name": "world"})
+ assert trigger.name == "Hello world"
+
+
[email protected]_test
+def
test_render_template_fields_empty_when_no_trigger_kwargs(create_task_instance):
+ """When start_trigger_args has no trigger_kwargs, template_fields should
be empty."""
+ op = DummyOperator(task_id="no_kwargs_task")
+ ti = create_task_instance(
+ task=op,
+ start_from_trigger=True,
+ start_trigger_args=StartTriggerArgs(
+
trigger_cls=f"{DummyTrigger.__module__}.{DummyTrigger.__qualname__}",
+ next_method="resume_method",
+ trigger_kwargs=None,
+ ),
+ )
+
+ trigger = DummyTrigger(name="Hello {{ name }}")
+ trigger.task_instance = ti
+
+ assert trigger.template_fields == ()
+
+ # Rendering with empty template_fields is a no-op
+ trigger.render_template_fields(context={"name": "world"})
+ assert trigger.name == "Hello {{ name }}"
