False positive with commands that cannot execute SQL

[nferraz]

This policy identifies the following string (used in a die) as potential target for SQL injections:

die "Select returned: $error";

Same thing with other functions that are commonly used for logging and error handling:

INFO "Delete record $id";
warn "Update returned: $error";
croak "Insert returned: $error";

Here's a patch to whitelist functions that are considered "safe": #23