0001 — Entity names state their window; a released id is never reused

Status: accepted (2026.11.0)

Context

HA derives an entity id by slugifying the English name, so a name is also an id. Up to 2026.10.1 the names were:

key	2026.10.1 name	id
radvor_rs_000	Precipitation now	precipitation_now
radvor_rs_060	Precipitation next 1h	precipitation_next_1h
radvor_rs_120	Precipitation next 1–2h	precipitation_next_1_2h
radvor_peak_1h_120	Peak hourly precipitation next 2h	peak_hourly_precipitation_next_2h
radvor_rv_max_intensity_060	Peak intensity next 1h	peak_intensity_next_1h
radvor_rv_max_intensity_120	Peak intensity next 1–2h	peak_intensity_next_1_2h
hymecng_precipitation_type	Precipitation type	precipitation_type
radolan_rw	Precipitation last 1h	precipitation_last_1h
radolan_rw_total	Precipitation total (hourly)	precipitation_total_hourly
radolan_sf_yesterday_total	Precipitation total (daily)	precipitation_total_daily

tests/entity_ids.py is the complete record by key, including what kept its id and what is new since.

Three things were wrong with them:

• Precipitation now was RS _000, mm over the past hour, named for its role; it read like a rate.
• next 1–2h needed a note that it is the second hour, not the coming two.
• RS _000 and RW both covered "the last hour" under unrelated names, and nothing in either said which hour.

Decision

A name states a window only when the window is part of the value, in three forms: last <N> (a measured window ending at the latest release), next <N> (a forecast window) and the calendar periods previous hour / yesterday. The RADVOR nowcast states windows in minutes, matching its 5-minute steps and the minutes_until attributes (next 60–120 min); RADOLAN keeps hours and days (last 24h keeps its released spelling, since a space would change its slug for nothing). now means the latest 5-minute analysis. Everything else carries no window.

So RS _000 is Precipitation last 60 min, RW (a clock hour, see 0002) is Precipitation previous hour, and no two names share a window, so none needs a source qualifier.

Keys did not change: existing installs keep their ids and only see new names; new installs get the new ids. No new id is one a released version gave another entity, so an id means one thing on every install, and HA's "recreate entity ids" on an old install cannot collide.

Alternatives turned down

• RS as precipitation_last_1h. On an old install RW still holds that id, so recreating ids would put RS on precipitation_last_1h_2.
• Source suffixes, (radar) / (gauge-adjusted). Carried briefly on the release branch after 2026.10.0, never shipped: once no two names share a window, the source is something the README explains, not a name.
• Renaming keys to match. A key is the unique-id suffix; changing it orphans the user's entity and its history.

Consequences

The README lists the old ids for installs from before 2026.11.0; a test checks it names every renamed one (tests/parser/test_docs.py). The setup test checks a new install's ids, and that none is an old id of another key.