fix a performance issue with dependent params

CHANGELOG.md

@@ -7,6 +7,7 @@
 #### Fixes
 
 * Your contribution here.
+* [#2127](https://github.com/ruby-grape/grape/pull/2127): Fix a performance issue with dependent params - [@dnesteryuk](https://github.com/dnesteryuk).
 * [#2126](https://github.com/ruby-grape/grape/pull/2126): Fix warnings about redefined attribute accessors in `AttributeTranslator` - [@samsonjs](https://github.com/samsonjs).
 * [#2121](https://github.com/ruby-grape/grape/pull/2121): Fix 2.7 deprecation warning in validator_factory - [@Legogris](https://github.com/Legogris).
 * [#2115](https://github.com/ruby-grape/grape/pull/2115): Fix declared_params regression with multiple allowed types - [@stanhu](https://github.com/stanhu).

UPGRADING.md

@@ -1,6 +1,28 @@
 Upgrading Grape
 ===============
 
+### Upgrading to >= 1.5.1
+
+#### Dependent params
+
+If you use [dependent params](https://github.com/ruby-grape/grape#dependent-parameters) with
+`Grape::Extensions::Hash::ParamBuilder`, make sure a parameter to be dependent on is set as a Symbol.
+If a String is given, a parameter that other parameters depend on won't be found even if it is present.
+
+_Correct_:
+```ruby
+given :matrix do
+  # dependent params
+end
+```
+
+_Wrong_:
+```ruby
+given 'matrix' do
+  # dependent params
+end
+```
+
 ### Upgrading to >= 1.5.0
 
 Prior to 1.3.3, the `declared` helper would always return the complete params structure if `include_missing=true` was set. In 1.3.3 a regression was introduced such that a missing Hash with or without nested parameters would always resolve to `{}`.

lib/grape/validations/params_scope.rb

@@ -61,8 +61,9 @@ def meets_dependency?(params, request_params)
         end
 
         return params.any? { |param| meets_dependency?(param, request_params) } if params.is_a?(Array)
-        return false unless params.respond_to?(:with_indifferent_access)
-        params = params.with_indifferent_access
+
+        # params might be anything what looks like a hash, so it must implement a `key?` method
+        return false unless params.respond_to?(:key?)
 
         @dependent_on.each do |dependency|
           if dependency.is_a?(Hash)