Throw a more descriptive error temporarily

src/lua/endpoints/edit_post.lua

@@ -77,6 +77,14 @@ local function edit_post(req)
 			error("Failed to get a post's hash while trying to make it unlisted")
 		end
 		local hash = stmnt_hash:get_value(0)
+		-- TODO: Remove this
+		-- Posts added before the unlisted feature will throw errors
+		-- when their hash is used to display them, or their url's.
+		-- when proper database migration tools are in place, remove
+		-- this bit of code.
+		if hash == -1 then
+			error("This post was created before the unlisting feature was added. Temporarily, this breaks. You will be able to unlist it in the future.")
+		end
 		loc = loc .. "?pwd=" .. util.encode_unlisted(hash)
 	end
 	--Turning something from not unlisted to unlisted should dirty all these