WaitSensor - time_to_wait templated

[raphaelauv]

time_to_wait should be templated so we can do

from airflow.sdk import DAG, Param
from airflow.providers.standard.sensors.time_delta import WaitSensor
with DAG(
        dag_id="my_dag",
        start_date=datetime(2024, 1, 1),
        schedule=None,
        catchup=False,
        params={
            "duration_minutes": Param(
                default=30,
                type="integer",
                minimum=1,
                description="Duration in minutes to wait.",
            )
        },
):

    WaitSensor(
        task_id="wait_for_duration",
        time_to_wait="{{ params.duration_minutes }}",
        deferrable=True
    )

[potiuk]

Thanks — and this one lands on the right side of a distinction that's been catching people out.

Making time_to_wait templated requires moving the int -> timedelta conversion out of __init__, because at construction time the value may still be "{{ ... }}". That's a value transformation, so deferring it to execute is correct — unlike a provision check ("was this argument passed?"), which per #70296 must stay in the constructor. Worth saying explicitly since several PRs in that campaign have moved the wrong kind.

I checked the one thing that can quietly break when a class declares template_fields: BaseSensorOperator doesn't define any, and neither does TimeDeltaSensor in the same module, so this is purely additive — nothing inherited gets shadowed.

_resolve_time_to_wait handling timedelta passthrough and int(value) for both native ints and rendered strings is the right shape, and the parametrisation over timedelta(minutes=1), 1, and "{{ 1*2 }}" covers all three input forms that can now reach it.

One small thought, not blocking: test_wait_sensor_templating_error pins Python's raw message, invalid literal for int() with base 10: 'nothing'. That's accurate but it's CPython's wording rather than ours, so the test is coupled to something we don't control. Wrapping the conversion to raise something like ValueError(f"time_to_wait must be a number of minutes or a timedelta, got {value!r}") would give users a better message and give the test something stable to assert.

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Drafted-by: Claude Code (Opus 5); reviewed by @potiuk before posting