Guardrails

A certain monk of the Spider Clan was attempting to use an email client library written by Laughing Monkey. The message he wished to send with it was simple, yet no matter how he tweaked his code the library either failed quietly or threw puzzling runtime exceptions.

The monk arranged a meeting with the author, wherein he politely expressed his frustration.

“Lamentably, the fault is your own,” replied the author with a bow. “Had you read the copious documentation I provided, you would have known that attachments should only be added after setting the message body. And while the setMessageText method does accept an untyped Object, the Object you provide must either be an array of Strings, a DomNode, or a BufferedInputReader. Also, you failed to note that certain destination addresses are silently ignored...”

The author continued on in this fashion, showing how the monk could have avoided each pitfall. Thus the monk returned to the Spider Clan’s abbey, suitably chastened.

Master Suku heard of this and summoned the author.

“I have read your documentation,” said Suku. “It is indeed the very model of thoroughness, worthy of emulation. Please take this hardcopy to the abbot, that others may learn from it.”

The author followed Suku down to the abbot’s chamber and pushed against its heavy door with all his might. When the door finally burst open the monk leaped backward in terror, for beyond it lay a sheer drop into blackness. His startled cry echoed against stone walls; the sound of water could be heard lapping far below.

“There is a ledge to your left, about as wide as your foot,” explained Suku. “Edge carefully around until you come to the opposite side of the well. There you will find iron rungs set into the wall, leading down to the waters where the abbot's bones await you. Take note: the ledge is slippery from damp, every third stone is set a few inches higher, every fifth is set lower, and every seventh is missing entirely. But if you keep all that in mind, the way is quite straightforward.”