sharedstate: don't send unchanged values

Setting a shared value to false would retain the old value since the
logic uses lua's fake "ternary"

sharedstate.lua

@@ -8,6 +8,10 @@ get_value, resolve_key, resolve_index
 --schema: similar to state_table, nested table only contains value
 local state_queue={}
 
+local function ternary(condition, val_if_true, val_if_false)
+	if condition then return val_if_true else return val_if_false end
+end
+
 -- we're protecting internal variables here, i'm *that* scared of writing bad
 -- code again.
 -- this section is purely for making sure the tables are in a consistent state
@@ -81,7 +85,7 @@ do
 	---@param value any value
 	---@param callback? function callback function
 	function set_value(key, value, callback)
-		logging.trace("set_value", key, value, callback)
+		logging.debug("sharedstate: key " .. tostring(key) .. " set to " .. tostring(value))
 		local initialized=init_key(key)
 		local entry=state_table[key]
 		if initialized then
@@ -90,7 +94,7 @@ do
 			entry["callback"]=callback
 
 		else
-			entry["value"]=value or entry["value"]
+			entry["value"]=ternary(value ~= nil, value, entry["value"])
 			callback_value(key)
 			entry["callback"]=callback or entry["callback"]
 			entry["old_value"]=value
@@ -179,8 +183,11 @@ function sharedstate.set(key, value)
 		local errormsg="sharedstate: Key " .. key .. " has not been initialized."
 		error(errormsg)
 	end
-	pings.sharedstate_recv(resolve_index(key), value)
-	-- pings.sharedstate_recv_named(key, value)
+	-- don't bother sending unchanged values
+	if value ~= get_value(key) then
+		-- pings.sharedstate_recv(resolve_index(key), value)
+		pings.sharedstate_recv_named(key, value)
+	end
 end
 
 ---Queue entries for sending