It takes 5 seconds on Google to find a myriad complaints about weird, unexpected, and downright incorrect things that PHP does. That wasn't the point of my reply. The point was that language choice CAN affect productivity. And having a bunch of gotchas is something that will negatively affect productivity. I simply gave the first example that popped into my head that actually tripped me up.

Unit tests would have caught this, if you wrote them.

Assuming you thought to test using a string that's all digits. You have to know about PHP's brokenness to even think to check that. In a sane language, it doesn't matter what the contents of the strings are, they're just strings.

>Unit tests would have caught this, if you wrote them.

If I hadn't considered string-number-keys in my code, I would also have forgotten about them in my unit tests. Maybe you're different.

My unit tests did not cover all possible strings, unfortunately.