The Black Enamel Box

Master Bawan posed this dilemma to the developers in his charge:

“When investigating strange behavior in the production environment, our most powerful weapon has always been debug messages: the more numerous and detailed, the better. Yet when used copiously, the formatting of such messages becomes expensive—needlessly expensive, for we exclude debug messages from our logs when we are not investigating problems. So which path is best? Safe but slow, or heedless but fast?”

“Wú,” said one of the nuns. “Everything may be logged, with minimal expense. Wrap every debug call within an if statement which verifies that debugging is on before bothering to format the message. We will only be slow when we need to be safe.”

Bawan considered this, and seemed pleased. He bade the nun implement her approach in an application that was presently being designed. As further reward for her cleverness he presented her with two enamel boxes.

“Open the red box immediately,” said Bawan, “but leave the black box shut tight. In time it will serve you.”

Inside the red box the nun discovered a small bowl full of succulent kiwi fruit, lychee, and white pears, resting on a bed of goji berries. These she enjoyed greatly that very evening. Afterwards she placed both boxes on a high shelf, and eventually forgot about them.

Two years later, after the system had undergone several enhancements, a minor production problem appeared—the first in many releases. The nun requested that the system be restarted in debug mode.

Suddenly, stack traces from NullPointerExceptions appeared on the screens of every user. The system had become completely unusable. As the nun stood aghast amid the chaos, master Bawan sidled up to her and whispered, “Now fetch the black box.”

When the lid was lifted a foul odor issued forth. Inside lay a small bowl filled with the mouldy, dessicated remains of what appeared to have once been kiwi fruit, lychee, pears and goji berries.

The nun requested that debug mode be turned off and then closed the box, enlightened.