如何在perl调试器中打破警告？

Question

I have a codepath that sometimes emits warnings. Since this path is used a lot of times I don't want to break on each pass. How can I break only on times it emits warnings?

Answer 1

You can use a "signal handler" for warnings and set a flag, then break when the flag is set.

our $warn_flag = 0;
$SIG{__WARN__} = sub { $warn_flag = 1; CORE::warn(@_) };

...

for $i (1 .. 1_000_000_000) {
    do_something_that_might_warn();
    $DB::single ||= $warn_flag;
    $warn_flag = 0;
}

Answer 2

use warnings qw(FATAL);

这会将警告转换为词法范围中的错误，这将自动导致调试器中断。