Introduce Grape::Validations::CoerceOptions value object

CHANGELOG.md

@@ -33,6 +33,7 @@
 * [#2712](https://github.com/ruby-grape/grape/pull/2712): Pass a `Grape::Exceptions::ErrorResponse` value object to `error_formatter#call` instead of separate kwargs - [@ericproulx](https://github.com/ericproulx).
 * [#2714](https://github.com/ruby-grape/grape/pull/2714): Drop unused `Grape::Middleware::Globals` and its `grape.request*` env constants - [@ericproulx](https://github.com/ericproulx).
 * [#2717](https://github.com/ruby-grape/grape/pull/2717): Convert `Grape::Exceptions::ErrorResponse` to a `Data` value object - [@ericproulx](https://github.com/ericproulx).
+* [#2722](https://github.com/ruby-grape/grape/pull/2722): Introduce `Grape::Validations::CoerceOptions` value object for the internal coerce options - [@ericproulx](https://github.com/ericproulx).
 * [#2721](https://github.com/ruby-grape/grape/pull/2721): Use an internal `Grape::Validations::SharedOptions` value object in `Validators::Base` (public `opts` Hash contract unchanged) - [@ericproulx](https://github.com/ericproulx).
 * [#2719](https://github.com/ruby-grape/grape/pull/2719): Move content-type helpers from `Middleware::Base` into `PrecomputedContentTypes` - [@ericproulx](https://github.com/ericproulx).
 * [#2716](https://github.com/ruby-grape/grape/pull/2716): Refactor `DSL::Routing#version`: guard clause, explicit kwargs in place of `**options`, and a `Grape::DSL::VersionOptions` value object stored internally - [@ericproulx](https://github.com/ericproulx).

lib/grape/validations/coerce_options.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Grape
+  module Validations
+    # Immutable value object describing how a parameter is coerced. Assembled
+    # by {ValidationsSpec#coerce_options} from the parsed +type+/+coerce_with+/
+    # +coerce_message+ declaration — never written by the user — and consumed
+    # by {ParamsScope#check_coerce_with} / {ParamsScope#validate_coerce} and by
+    # {Validators::Validators::CoerceValidator} (which receives it as its
+    # +options+ argument).
+    #
+    # All three fields may be +nil+ (e.g. a remountable API evaluated on its
+    # base instance has no resolved +type+ yet).
+    # +coerce_method+ (not +method+) avoids shadowing +Object#method+.
+    CoerceOptions = Data.define(:type, :coerce_method, :message) do
+      def initialize(type: nil, coerce_method: nil, message: nil)
+        super
+      end
+    end
+  end
+end

lib/grape/validations/params_scope.rb

@@ -348,13 +348,13 @@ def validates(attrs, validations)
         end
       end
 
-      # Enforce correct usage of :coerce_with on a coerce_options hash.
+      # Enforce correct usage of :coerce_with on a CoerceOptions.
       # We do not allow coercion without a type, nor with +JSON+ as a type
       # since that defines its own coercion method.
       def check_coerce_with(coerce_options)
-        return unless coerce_options[:method]
-        raise ArgumentError, 'must supply type for coerce_with' unless coerce_options[:type]
-        return unless SPECIAL_JSON.include?(coerce_options[:type])
+        return unless coerce_options.coerce_method
+        raise ArgumentError, 'must supply type for coerce_with' unless coerce_options.type
+        return unless SPECIAL_JSON.include?(coerce_options.type)
 
         raise ArgumentError, 'coerce_with disallowed for type: JSON'
       end
@@ -373,7 +373,7 @@ def validate_coerce(spec, attrs)
         # configuration[:some_type] evaluates to nil. Skipping instantiation
         # here is correct — the real mounted instance will replay this step
         # with the actual type value.
-        return unless coerce_options[:type]
+        return unless coerce_options.type
 
         validate('coerce', coerce_options, attrs, spec.required?, spec.shared_opts)
       end

lib/grape/validations/validations_spec.rb

@@ -65,7 +65,7 @@ def required?
       end
 
       def coerce_options
-        { type: @coerce_type, method: @coerce_method, message: @coerce_message }
+        CoerceOptions.new(type: @coerce_type, coerce_method: @coerce_method, message: @coerce_message)
       end
 
       private

lib/grape/validations/validators/coerce_validator.rb

@@ -9,13 +9,18 @@ class CoerceValidator < Base
         def initialize(attrs, options, required, scope, opts)
           super
 
-          raw_type = @options[:type]
+          # +@options+ is a Grape::Validations::CoerceOptions. +Base#message+
+          # can't see a custom message off a Data (it probes Hash-like
+          # +key?+), so restore it here to preserve `type: { value:, message: }`.
+          @exception_message = @options.message unless @options.message.nil?
+
+          raw_type = @options.type
           type = hash_like?(raw_type) ? raw_type[:value] : raw_type
           @converter =
             if type.is_a?(Grape::Validations::Types::VariantCollectionCoercer)
               type
             else
-              Types.build_coercer(type, method: @options[:method])
+              Types.build_coercer(type, method: @options.coerce_method)
             end
         end