Deprecation Handler for Rails that ignores deprecations emitted more than once, or custom message regular expressions

deprecation_handler.rb

# Override Deprecation warnings to only show each unique deprecation message
# once instead of repeating it every time the deprecated code is run.
# This can help prevent the "wall of deprecations" when one commonly-called
# action produces a deprecation over and over again.
#
# You can also add regular expressions to the `@@ignored` array to silence them.
#
if Rails.env.test?
  module ActiveSupport
    class Deprecation
      module Reporting
        # Use Regexes to match against ignored deprecations.
        @@ignored = [/halt_callback_chains_on_return_false/]
        @@seen = []

        def warn(message = nil, callstack = nil)
          return if silenced ||
            @@ignored.detect { |regex| message.match?(regex) } ||
            @@seen.include?(message)

          # Add to seen list, so we don't warn again.
          @@seen << message

          # This is the normal Rails deprecation handling code.
          callstack ||= caller_locations(2)
          deprecation_message(callstack, message).tap do |m|
            behavior.each do |b|
              if Rails.version > '6.0.0'
                b.call(m, callstack, deprecation_horizon, gem_name)
              else
                b.call(m, callstack)
              end
            end
          end
        end
      end
    end
  end
end