qbs clean does not respect buildVariant

In general, when I type “qbs buildVariant:release clean” I would expect the build directory for the release build (e.g. build/qt-macports-release/) to be cleaned, but that the directories for other build variants (e.g. build/qt-macports-debug/ or build/qt-mingw-release/ ) to be left alone. At the moment, qbs clean removes build/ completely!

Is my expectation here wrong? If so, I'd say there's a need for a “cleanVariant” or equivalent command, which cleans the build only for one variant rather than for all! I would prefer if “clean” respected buildVariant though.