DateTimeSensorAsync crashes Dag parsing with templated target_time + start_from_trigger=True

[Lee-W]

Apache Airflow version

main (also reproduced against current released 3.x)

What happened

DateTimeSensorAsync declares target_time as a template_fields member (rendered via Jinja against the run context at task-execution time), but its __init__ calls timezone.parse(self.target_time) at Dag-parse time when start_from_trigger=True — before Jinja rendering has happened. If target_time is a template string (the normal, documented use case for this field), this raises a parser error and crashes parsing of the entire Dag
file, not just the task.

This is the same root-cause pattern fixed for TimeSensor in #69610 (parse-time handling of a value that can only correctly be resolved at/near task-execution time), but with a more severe symptom: instead of silent dag_version churn, the whole Dag fails to parse.

Reproduction

from __future__ import annotations
import pendulum
from airflow.sdk import DAG
from airflow.providers.standard.sensors.date_time import DateTimeSensorAsync

with DAG(dag_id="repro", schedule=None, start_date=pendulum.datetime(2026, 1, 1, tz="UTC")):
    DateTimeSensorAsync(
        task_id="t",
        target_time="{{ data_interval_end.tomorrow().replace(hour=1) }}",
        start_from_trigger=True,
    )

Raises at Dag-parse time:

pendulum.parsing.exceptions.ParserError: Invalid date string: {{ data_interval_end.tomorrow().replace(hour=1) }}

There is currently no test coverage for DateTimeSensorAsync combining a templated target_time with start_from_trigger=True.

What you think should happen instead

Check whether a string is passed when start_from_trigger=True. static datetime should be fine

How to reproduce

See reproduction script above; raises immediately on Dag parse.

Operating System

N/A (reproduced via breeze container, standard provider)

Deployment

Other

Deployment details

Found while reviewing #69610 (TimeSensor fix for a related parse-time issue).

Anything else

Related: #69610, #69543

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

[AIMindCrafter]

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