What are the common pitfalls when using Perl's eval?

Question

What are the common pitfalls associated with Perl\'s eval, which might make you choose to use a module such as Try::Tiny?

Answer 1

In addition to the answers above, I would add...

• eval is affected by the global $SIG{__DIE__} handler causing action at a distance.
• It is easy for a novice to confuse eval BLOCK and eval STRING, since they appear to do the same thing, but one is a security hole.

Try::Tiny has its own pitfalls, the biggest being that while it looks like a block it is actually a subroutine call. That means this:

eval {
    ...blah blah...
    return $foo;
};

and this:

try {
    ...blah blah...
    return $foo;
};

do not do the same thing. These are laid out in the CAVEATS section of the Try::Tiny docs. That said, I'd recommend it over eval.