Yep, that's a pattern I've applied before. It's not the worst, but I don't think it has the clarity that this would have:

    key, value ?= item.split("=", 1)

Modulo bike shedding over the actual syntax, of course.

(Edit: the semantics of this could be even more generic, like Ruby's `[...] rescue value` syntax for turning any raised exception into a default value instead.)