There’s an epidemic among programmers of “warning obliviousness.” That is, simply choosing to ignore the highly pertinent warnings that emerge from the compiler as it passes through your source files. This nasty habit not only risks masking bugs in currently shipping products, but leaves the door wide open for future bugs to worm their way into code. I’m frustrated and appalled by the number of projects I’ve worked on (or simply compiled) where a “clean build” consists of dozens or hundreds of warning lines followed by a friendly “Build Succeeded.” That’s a bald-faced lie!
In general it is a good, no a great idea to maintain warning-free source code. Warnings keep you out of a great deal of trouble. To that end I usually configure my projects such that most if not all warnings are enabled in the compiler, and that warnings are to be treated as errors. This can be annoying and cumbersome while prototyping ideas, but it’s always a good idea for at least your “Release” build style. While following this advice might not literally save your life, it will ultimately give you more time to enjoy the finer things that exist outside of your debugger.
In a follow-up post, I’ll share an amusing story about how I recently fell into the clutches of warning obliviousness, and was lucky enough to come out unscathed (after a several hours long battle with a vexing bug). In this post, I’d like to talk a bit about a possible real-life cause of warning obliviousness: fake and stupid warnings.
We are desensitized to bits of advice labeled “warnings,” due to the outrageous abuse of the term in our everyday lives.
Some of the fakest warnings are the insanely long paragraphs that fill product labels and explain in a roundabout way that “real bad stuff” will happen if you misuse the product. The thing that makes these warnings fake is that they fail to describe a real cause or a real effect. I’m looking at a package of Fisherman’s Friend cough drops. The warnings on this package take up more than half of the text on the package, and after forcing myself to read through the whole damn thing, I now know that I shouldn’t take these simple menthol drops for chronic emphysema, sore throats that last more than 2 days, or sore mouth problems that last longer than 7 days. Phew! Glad I know the magic numbers! How are intelligent people supposed to cope with this kind of warning overkill? The package should say: “Warning: This product is exceedingly safe for treatment of common symptoms, but don’t let that stop you from visiting a doctor about your serious life-threatening illness.”
How about those little “silica gel packs?” The desiccant packages come with a variety of products where manufacturers want the product to stay dry until it gets to you. We’re so familiar with them that we often joke about the “Do Not Eat” warnings that are always included. Did anybody ever really think it was OK to eat them before the warnings were put on? Hmm, I just got a new leather purse and what do you know – it came with a fun pouch of edible sand!
On my bathroom sink I find two warning-laden products: Colgate toothpaste, and SoftSoap liquid soap (also by Colgate). Each of these contains warnings to “keep out of the reach of children under 6 years of age.” Or else what? They might squeeze it into their ears and go deaf? 7 year olds are immune to the allure of dangerous bathroom products? I guess we’re supposed to assume that kids under 6 will eat anything, but isn’t that part of baby-proofing a house? If you are running around looking at all your products for this wisdom, you’re in a sad state: “Hmm, the shampoo doesn’t have a warning, honey! So it must be safe for little Billy to eat.” The toothpaste includes an additional warning: “If more than used for brushing is accidentally swallowed, get medical help or contact a Poison Control Center right away.” The vagueness of both the quantity and the outcome are ridiculous. And excuse me, but I am not in the habit of swallowing even the amount I use for brushing. And how exactly would swallowing more than that be classified as an accident? Whoops, I did it again!
Incidentally, both the SoftSoap and the toothpaste include a chemical called triclosan. The toothpaste, which goes in your mouth, contains about three times the amount as the soap, which goes on your hands (“Warning: For external use only”). On the toothpaste it’s identified as an “anti-gingivitis” agent, while its bacteria-busting attributes are proudly highlighted on the soap. I guess people who market toothpaste don’t think “Antibacterial Toothpaste – Three Times Stronger than Soap!” has a strong ring to it.
I have to give some credit to Proctor and Gamble, whose Dawn dishwashing soap contains a brief and rather meaningful paragraph of advice. “If Dawn gets in eyes, rinse thoroughly with water. If swallowed, drink a glass of water to dilute.” And to their great credit, they don’t label these tidbits “warnings” at all. Because they aren’t warnings, they’re post-accident advice. A warning is “Don’t drink Dawn because it will make you feel funny and you’ll have to dilute it with water.” I guess Dawn realized they didn’t need to give that warning, because doing so would be stupid, and therefore make customers think that Dawn thinks they’re stupid.
It’s hard to draw a line between fake and stupid when it comes to warnings. You can always argue that somebody out there needs the warning on the product in order to use it in a safe manner. Then again, my kitchen knives aren’t engraved with “Warning: Don’t stab self,” (yet?) and I seem to be getting along just fine.
Even the warnings that could be really meaningful, I’m often left with less useful information than I should have. In the case of poisons, it’s almost always something along the lines of “WARNING: Do not swallow. May cause light-headeness and nausea. Contact your poison control center immediately.” This makes it difficult to tell the difference between “poison like arsenic” and “poison like a Gin and Tonic.”
So when programmers come in from the storm of everyday warnings and look at their compiler, chugging away and spewing warnings left and right, it must feel very natural to ignore them. “Take this curve at 30 miles per hour.” Uh-huh. “Hold railing while climbing stairs.” Oh-yeah. “Do not wrap babies in plastic bags.” OK. “Installing this program will render your computer unusable.” Great! “Undefined function: DoImportantStuff()”. Yeah, whatever.
At least in real life, there is a system in place for escalating warnings to a higher, harder to ignore level. Police and ambulance warnings are accompanied by flashing lights and sirens. These mean “get the hell out of the way” and most people still take them pretty seriously. In the programming world, we only get one grade of warning. Why is that? Because every warning falls into the same category from the compiler’s perspective: “might cause a bug, but heck if know.” In this way the compiler warning is sort of a fake warning, because it doesn’t describe a real effect. But it’s a cry for help. The compiler needs us, the brilliant engineers, to intervene for the well-being of the program and its users. When you ignore these warnings, you’re letting your compiler, your users, and yourself down. And you’ll pay dearly for it one day.