SMTPNotifier not working on HITLBranchOperator

[silasdoehler]

Apache Airflow Provider(s)

standard, smtp

Versions of Apache Airflow Providers

apache-airflow-providers-smtp==2.3.1
apache-airflow-providers-standard==1.9.1

Apache Airflow version

3.1.1

Operating System

devcontainer on macos

Deployment

Other Docker-based deployment

Deployment details

local development: i use astro cli in a devcontainer

What happened

I try to integrate a HITLBranchOperator in my DAG, with an SMTPNotifier for notifications. SMTP is correctly configured (at least i can send emails from my DAGs using send_email_smtp()), the connection is smtp_default.

This is the code snippet (error is the same, no matter if i use SMTPNotifier and send_smtp_notification):

review_export_task = HITLBranchOperator(
        task_id = "review_export",
        subject="Please check the export provided in S3 bucket. See the previous task for detailed errors.",
        options=["send_invoices_export", "abort_export_creation"],
        notifiers=[
            send_smtp_notification(
                from_email="your_mail@example.com",
                to="my_mail@example.com",
                subject="Export needs to be checked",
                html_content="Please check the export provided in S3 bucket"
            )
        ]
    )

When running the task i get this error:

Failed to send notification (sync): Connection.__init__() got an unexpected keyword argument 'ti_id' source=airflow.providers.smtp.notifications.smtp.SmtpNotifier loc=notifier.py:140
[2025-10-28 16:22:18] ERROR - Task failed with exception source=task loc=task_runner.py:994
TypeError: Connection.__init__() got an unexpected keyword argument 'ti_id'
File "/usr/local/lib/python3.12/site-packages/airflow/sdk/execution_time/task_runner.py", line 920 in run

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/execution_time/task_runner.py", line 1307 in _execute_task

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/bases/operator.py", line 416 in wrapper

File "/usr/local/lib/python3.12/site-packages/airflow/providers/standard/operators/hitl.py", line 152 in execute

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/bases/notifier.py", line 138 in __call__

File "/usr/local/lib/python3.12/site-packages/airflow/providers/smtp/notifications/smtp.py", line 152 in notify

File "/usr/local/lib/python3.12/site-packages/airflow/providers/smtp/hooks/smtp.py", line 83 in __enter__

File "/usr/local/lib/python3.12/site-packages/airflow/providers/smtp/hooks/smtp.py", line 121 in get_conn

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/bases/hook.py", line 61 in get_connection

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/definitions/connection.py", line 226 in get

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/execution_time/context.py", line 185 in _get_connection

File "/usr/local/lib/python3.12/site-packages/airflow/sdk/execution_time/context.py", line 116 in _process_connection_result_conn

What you think should happen instead

A mail notification should be sent

How to reproduce

Just add this task to a DAG

Anything else

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[tirkarthi]

cc: @Lee-W

[amoghrajesh]

Added it to 3.1.2 milestone

[Lee-W]

In the latest main, the issue now locates in

airflow/task-sdk/src/airflow/sdk/execution_time/context.py

Lines 158 to 170 in 278a756

	for secrets_backend in backends:
	try:
	conn = secrets_backend.get_connection(conn_id=conn_id) # type: ignore[assignment]
	if conn:
	SecretCache.save_connection_uri(conn_id, conn.get_uri())
	_mask_connection_secrets(conn)
	return conn
	except Exception:
	log.debug(
	"Unable to retrieve connection from secrets backend (%s). "
	"Checking subsequent secrets backend.",
	type(secrets_backend).__name__,
	)

I'm now using a the HITL example dag but change the notify function as

    def notify(self, context: Context) -> None:
        from airflow.sdk.definitions.connection import Connection

        conn = Connection.get("smtp_default")
        url = HITLOperator.generate_link_to_ui_from_context(
            context=context,
            base_url="http://localhost:28080",
        )
        self.log.info(self.message)
        self.log.info("Url to respond %s", URL)

It's not able to get the connection. But the execution API returns 200.

[amoghrajesh]

Yeah, I do not see the reported error too, I see this:

[2025-10-29 19:17:32] ERROR - Task failed with exception source=task loc=task_runner.py:996
AirflowException: SMTP connection is not found.
File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/task_runner.py", line 934 in run

File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/task_runner.py", line 1331 in _execute_task

File "/opt/airflow/task-sdk/src/airflow/sdk/bases/operator.py", line 416 in wrapper

File "/opt/airflow/providers/standard/src/airflow/providers/standard/operators/hitl.py", line 152 in execute

File "/opt/airflow/task-sdk/src/airflow/sdk/bases/notifier.py", line 138 in __call__

File "/opt/airflow/providers/smtp/src/airflow/providers/smtp/notifications/smtp.py", line 152 in notify

File "/opt/airflow/providers/smtp/src/airflow/providers/smtp/hooks/smtp.py", line 80 in __enter__

File "/opt/airflow/providers/smtp/src/airflow/providers/smtp/hooks/smtp.py", line 120 in get_conn

AirflowNotFoundException: The conn_id `smtp_default` isn't defined
File "/opt/airflow/providers/smtp/src/airflow/providers/smtp/hooks/smtp.py", line 118 in get_conn

File "/opt/airflow/task-sdk/src/airflow/sdk/bases/hook.py", line 61 in get_connection

File "/opt/airflow/task-sdk/src/airflow/sdk/definitions/connection.py", line 225 in get

File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/context.py", line 175 in _get_connection

[amoghrajesh]

Figured it out, pushing a fix: #57437