In my opionion, the design of the DBIx::Password module is brain-damaged. Maybe I'm missing something, but it would be much easier to have the user information in a separate file with a standard layout, so you can easily scan the file for double usernames, etc, etc. Maybe it's done for performance or some other reason.

The problem you have now is that you have to scan through the Password.pm source code, and add code at the correct lines. Or thinking along another line, you could also automate the interaction with the Makefile.PL script which then inserts the information (possibly from a file you maintain), and let Makefile.PL do the hard work of generating the module with the desired user information.

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All that is gold does not glitter...