fix(light): complete brightness range clamping#5195
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The previous workaround (c33c67b) only covered the regular brightness path. The white brightness path (ATTR_WHITE) had the same issue. It also used duplicated logic that was susceptible to future drift. Extract the brightness range scaling algorithm into a helper method and apply it to both ATTR_BRIGHTNESS and ATTR_WHITE paths. This ensures both paths preserve the intended behavior (snapping bright==1 to the minimum) while safely clamping values that fall below the target range. Test coverage expanded significantly to cover both paths and all edge cases (wide ranges, proportional mid-values, upper bounds).
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May 31, 2026 18:47
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Jun 5, 2026
* fix(light): complete brightness_to_value range clamping The previous workaround (c33c67b) only covered the regular brightness path. The white brightness path (ATTR_WHITE) had the same issue. It also used duplicated logic that was susceptible to future drift. Extract the brightness range scaling algorithm into a helper method and apply it to both ATTR_BRIGHTNESS and ATTR_WHITE paths. This ensures both paths preserve the intended behavior (snapping bright==1 to the minimum) while safely clamping values that fall below the target range. Test coverage expanded significantly to cover both paths and all edge cases (wide ranges, proportional mid-values, upper bounds). * refactor(light): clarify brightness DP helper name * refactor(light): clarify HA brightness helper naming --------- Co-authored-by: Yuris Auzins <zuz666@users.noreply.github.com>
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Summary
Problem
Home Assistant's color_util.brightness_to_value() can return a value below the configured device range minimum for low HA brightness values. For example, brightness_to_value((1, 6), 20) returns 0.470588, which later rounds to 0 and fails validation against the 1..6 DP range.
The workaround in c33c67b fixes this for regular brightness, but the white brightness path still used the old conversion logic. This PR applies the same behavior to both paths and keeps the existing bright == 1 behavior that makes the physical device minimum reachable on wide ranges.
Related discussion: #5123
Test Plan