Crash when recycling default stairs

[Caellian]

Crash when recycling default stairs

[Calinou]

Adding

if not cost then
    return 0
end

before line 261 (if (incost + cost) > maxcost then in circular_saw.allow_metadata_inventory_put) prevents crash from occurring, but a better approach would be to keep track of aliased nodes in aliases.lua try mapping old node into a new one to consistently calculate cost.

Maybe we should return an extremely high cost in this case? We should avoid introducing a duplication bug while fixing this 🙂

[Caellian]

Maybe we should return an extremely high cost in this case? We should avoid introducing a duplication bug while fixing this

Returning 0 from circular_saw.allow_metadata_inventory_put prevents the item from being inserted.
Returning a high cost from circular_saw:get_cost is logically worse than returning nil. Cost for an unhandled item does not exist, thus it makes sense for circular_saw:get_cost to return nil.

I suggested using aliases instead of simply returning 0 as it would result in expected behaviour instead of preventing players from recycling default stairs which might be confusing if they don't know what's going on.

So something along the lines of:

function circular_saw:get_cost(inv, stackname)
	local name = minetest.registered_aliases[stackname] or stackname
	for i, item in pairs(inv:get_list("output")) do
		if item:get_name() == name then
			return circular_saw.cost_in_microblocks[i]
		end
	end
end

Right, that fixes the problem. I'll submit a PR.