HA logs a removal warning (2027.8) every time this name is accessed on
releases that carry UnitOfDensity, attributed straight to this
integration since it's a plain module-level import. UnitOfDensity is
the replacement, but hacs.json's floor (2025.1.0) predates it existing
at all -- pytest-homeassistant-custom-component 0.13.316, the newest
available, still has no UnitOfDensity either, so this can't be a
static import on either branch without breaking support for part of
the version range.
Resolved with a runtime getattr instead: reads UnitOfDensity off the
homeassistant.const module if present and uses its
MICROGRAMS_PER_CUBIC_METER member, otherwise falls back to the plain
(un-deprecated, on those older releases) constant. The getattr
short-circuits before the deprecated name is ever touched on a release
new enough to have UnitOfDensity, so the warning stops firing there
without dropping support for anything still on the old one. Same
feature-detection shape _relabel_particulate_statistics already uses a
few lines down for new_unit_class.
Verified the resolution logic directly: against the installed HA
(2026.2.3, pre-UnitOfDensity) it resolves to the plain constant with no
warning; a simulated future homeassistant.const with UnitOfDensity
present resolves to it without ever touching the deprecated name (a
guard that raises on that access never fires).
Full suite (1573 tests), ruff, and `ty check custom_components tests`
(CI's exact invocation) all pass.
Marc Billow
f5d9f0e31b