Because of how this middleware works, it may not be easy to debug Lint
errors when you encounter one, unless youre writing a PSGI web server
or a framework.
For example, when youre an application developer (user of some
framework) and see errors like:
Body should be an array ref or filehandle at lib/Plack/Middleware/Lint.pm line XXXX
theres no clue about which line of your application produces that
Were aware of the issue, and have a plan to spit out more helpful
errors to diagnose the issue. But until then, currently there are some
workarounds to make this easier. For now, the easiest one would be to
enable Plack::Middleware::REPL outside of the Lint middleware,
plackup -e enable "REPL"; enable "Lint" app.psgi
so that the Lint errors are caught by the REPL shell, where you can
inspect all the variables in the response.