preprocessing.coverage.assert_frontier_fresh

preprocessing.coverage.assert_frontier_fresh(index, required_last)

Raise CoverageError if the data frontier is stale.

Corresponds to the first guard in the operational assert_coverage (script line ~457): index.max() < required_last means no new data has arrived since the required cutoff and forecasting would extrapolate into a data void.

The comparison is strict (<): index.max() == required_last is a passing boundary (data is exactly as fresh as required).

Parameters

Name	Type	Description	Default
index	pd.DatetimeIndex	DatetimeIndex of the interim data frame whose maximum timestamp is compared against the freshness requirement.	required
required_last	pd.Timestamp	Minimum acceptable value for `index.max()`. Callers typically pass `today - pd.Timedelta(hours=1)` (the last publishable complete UTC hour before `now`).	required

Raises

Name	Type	Description
	CoverageError	When `index.max() < required_last`, naming both the observed maximum and the required value.

Examples

import pandas as pd
from spotforecast2_safe.preprocessing.coverage import assert_frontier_fresh
from spotforecast2_safe.exceptions import CoverageError

# Passing: index reaches the required timestamp.
idx = pd.date_range("2026-06-10 00:00", periods=24, freq="h", tz="UTC")
required = pd.Timestamp("2026-06-10 00:00", tz="UTC")
assert_frontier_fresh(idx, required)   # no exception

# Failing: data ends one hour before the requirement.
try:
    assert_frontier_fresh(idx, pd.Timestamp("2026-06-10 23:00", tz="UTC"))
except CoverageError as exc:
    print(exc)