Add applied_filter_params, the values as a copy

[Fivell]

Why

filtering_params is documented as the values handed to Ransack, and that is exactly what it returns: a Hash with String keys, the same object the filters form and the canonicalizing redirect are computed from.

That is the right contract for the framework path, and an awkward one for a page that does its own work with those values. Such a page — one that overrides find_collection without super, talks to something that is not an ActiveRecord::Relation, or builds a drill-down or export link — usually has to translate the filters first: rename a key an input suffixed (time_start_gteq_datetime → time_start_gteq), turn a sentinel select value into a different predicate (status_eq=null → status_null=true). Done on the returned Hash, that edits what fills the filters form and what the redirect decision is computed from; done safely, every site repeats .with_indifferent_access or symbolize_keys plus a dup of its own.

What

# @return [ActiveSupport::HashWithIndifferentAccess]
def applied_filter_params
  filtering_params.with_indifferent_access
end

Registered as a helper next to filtering_params, so a view can call it too.

• filtering_params is untouched — same contract, same type, same object semantics.
• The new method's promise is the copy: a caller may read it by symbol and mutate it freely.

Tests

spec/data_access_spec.rb — one example reads by symbol a value the request spelled as a String; the other mutates the result the way a translating page does (applied[:position_gt] = applied.delete(:position_eq)) and asserts both that filtering_params is unchanged and that Ransack still searched the original.

Full suite: 200 examples, 0 failures. Version bumped to 1.2.0.

Also fixes a stale annotation: filtering_params was documented as [Hash, ActionController::Parameters], but requested_filtering_params unwraps Parameters via to_unsafe_h, so it is always a Hash.

[Copilot]

🟡 Changes recommended

Shared mutable String values allow edits through the new helper to alter the original filters.

1 open issue

• Deep-duplicate filtering params to prevent shared String mutations · New

What changed in this PR

Adds applied_filter_params for controllers and views to translate effective filters without changing the existing filtering_params API.

Changes:

• Adds and exposes the indifferent-access copy helper.
• Documents its intended usage and tests symbol access and key mutation.
• Corrects a return-type annotation and bumps the version to 1.2.0.

File	Description
spec/​data_access_spec.rb	Tests helper access and key-mutation isolation.
README.md	Documents the new helper.
lib/​active_admin_filter_extensions/​version.rb	Bumps version to 1.2.0.
lib/​active_admin_filter_extensions/​filter_defaults.rb	Implements the helper and corrects the annotation.
lib/​active_admin_filter_extensions.rb	Exposes the helper to views.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

The focused change preserves existing behavior and fixes the previously reported shared-value issue with regression coverage.

No open issues 🎉

1 resolved since last review

• Deep-duplicate filtering params to prevent shared String mutations

_{Review effort: Balanced}