Use of Assertions

One gotcha it doesn't mention: don't rely on assertions for security-critical input checks. I sometimes see this sort of thing:

    char buf[200];
    assert(foo_len < 200);
    memcpy(buf, foo, foo_len);

But if asserts get turned off in a release build, it's suddenly vulnerable to buffer overflow attacks.

Python assert checking is removed when the code is run with python -O ("optimize"), so it shouldn't be used to validate user input, checking for critical conditions, etc. It is just a defensive programming and debugging tool.