main.lua

local function checkjoint(world)
	local joint = world:getJoints()[1]
	print(string.format('type() = %s, getType() = %s', joint:type(), joint:getType()))
	joint:setMotorEnabled(true)
end

function love.load()
	local world = love.physics.newWorld()
	local a = love.physics.newBody(world, 0, 0)
	local b = love.physics.newBody(world, 0, 0)
	love.physics.newRevoluteJoint(a, b, 0, 0) -- No reference kept

	-- The object obtained from World:getJoints has the proper RevoluteJoint
	-- metatable, and setMotorEnabled can be called
	checkjoint(world)

	-- Triggering manually for test, would happen eventually
	collectgarbage()

	-- Now that the joint has been garbage collected, it is recreated
	-- incorrectly when retrieved again:
	-- Its :type() is now 'Joint' (the base class, not the specific
	-- RevoluteJoint), but its :getType() is still 'revolute', and
	-- .setMotorEnabled no longer exists
	checkjoint(world)
end