HALightTargetProcessor and Z2MLightTargetProcessor used to carry
character-for-character identical _swap_color_source method bodies
(audit finding C5) — only the log prefix differed. Extract the body
into a free function ``swap_color_source(processor, new_kind,
new_color_vs_id, *, log_label)`` in a new ``light_target_helpers``
module. Each processor's _swap_color_source now delegates to the helper
and then clears its per-entity history (``_previous_colors`` /
``_previous_on``) — that bit stays on the processor because it's per-
target state, not colour-source state.
Scope deliberately narrower than the full BaseLightTargetProcessor ABC
the audit gestured at: the 76 read sites for the per-processor colour
state across the two files made a full state-composition refactor too
risky for the live LED control loop. The free-function helper is the
minimum-blast-radius way to delete the duplication while leaving WLED
(which has no value-stream-vs-CSS dispatch) untouched.
The helper standardises both warning messages on HA's original wording
("failed to acquire color VS stream" / "failed to re-acquire CSS
stream") so existing log alerts/grep patterns keep working.
A LightTargetSwapState Protocol under TYPE_CHECKING documents the
expected processor surface; no runtime enforcement (acceptable trade-
off vs a 76-site touchpoint).
Tests: 7 new tests cover the release+acquire ordering, the not-running
no-op path, the manager-error-swallowing behaviour, the empty-id
short-circuit, and the missing-manager (TargetContext(None, None))
fallback. 354 existing storage + API + e2e + processing tests stay
green; ruff clean.
alexei.dolgolyov
29bdacf69a