Support custom validators autoloading in Rails >= 6

.rubocop_todo.yml

@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2021-12-05 16:55:50 UTC using RuboCop version 1.23.0.
+# on 2021-12-20 18:08:03 UTC using RuboCop version 1.23.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -20,7 +20,7 @@ Lint/AmbiguousBlockAssociation:
   Exclude:
     - 'spec/grape/dsl/routing_spec.rb'
 
-# Offense count: 41
+# Offense count: 40
 # Configuration parameters: AllowedMethods.
 # AllowedMethods: enums
 Lint/ConstantDefinitionInBlock:
@@ -72,7 +72,7 @@ Metrics/BlockLength:
 # Offense count: 9
 # Configuration parameters: CountComments, CountAsOne.
 Metrics/ClassLength:
-  Max: 298
+  Max: 305
 
 # Offense count: 30
 # Configuration parameters: IgnoredMethods.
@@ -173,13 +173,7 @@ RSpec/EmptyExampleGroup:
     - 'spec/grape/dsl/configuration_spec.rb'
     - 'spec/grape/validations/attributes_iterator_spec.rb'
 
-# Offense count: 1
-# Cop supports --auto-correct.
-RSpec/EmptyLineAfterSubject:
-  Exclude:
-    - 'spec/grape/dsl/logger_spec.rb'
-
-# Offense count: 500
+# Offense count: 501
 # Configuration parameters: CountAsOne.
 RSpec/ExampleLength:
   Max: 57
@@ -225,7 +219,7 @@ RSpec/IteratedExpectation:
   Exclude:
     - 'spec/grape/middleware/formatter_spec.rb'
 
-# Offense count: 90
+# Offense count: 84
 RSpec/LeakyConstantDeclaration:
   Enabled: false
 
@@ -250,16 +244,16 @@ RSpec/MissingExampleGroupArgument:
   Exclude:
     - 'spec/grape/middleware/exception_spec.rb'
 
-# Offense count: 755
+# Offense count: 756
 RSpec/MultipleExpectations:
   Max: 16
 
-# Offense count: 11
+# Offense count: 32
 # Configuration parameters: AllowSubject.
 RSpec/MultipleMemoizedHelpers:
   Max: 10
 
-# Offense count: 2118
+# Offense count: 2121
 # Configuration parameters: IgnoreSharedExamples.
 RSpec/NamedSubject:
   Enabled: false
@@ -318,13 +312,12 @@ RSpec/SubjectStub:
     - 'spec/grape/middleware/stack_spec.rb'
     - 'spec/grape/parser_spec.rb'
 
-# Offense count: 25
+# Offense count: 24
 # Configuration parameters: IgnoreNameless, IgnoreSymbolicNames.
 RSpec/VerifiedDoubles:
   Exclude:
     - 'spec/grape/api_spec.rb'
     - 'spec/grape/dsl/inside_route_spec.rb'
-    - 'spec/grape/dsl/logger_spec.rb'
     - 'spec/grape/integration/rack_sendfile_spec.rb'
     - 'spec/grape/middleware/formatter_spec.rb'
     - 'spec/grape/validations/multiple_attributes_iterator_spec.rb'
@@ -364,7 +357,7 @@ Style/OptionalBooleanParameter:
     - 'lib/grape/validations/types/primitive_coercer.rb'
     - 'lib/grape/validations/types/set_coercer.rb'
 
-# Offense count: 146
+# Offense count: 145
 # Cop supports --auto-correct.
 # Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
 # URISchemes: http, https

CHANGELOG.md

@@ -3,6 +3,7 @@
 #### Features
 
 * [#2196](https://github.com/ruby-grape/grape/pull/2196): Add support for `passwords_hashed` param for `digest_auth` - [@lHydra](https://github.com/lhydra).
+* [#2204](https://github.com/ruby-grape/grape/pull/2204): Support custom validators autoloading in Rails 6 - [@dm1try](https://github.com/dm1try).
 * Your contribution here.
 
 #### Fixes

lib/grape.rb

@@ -246,5 +246,5 @@ module ServeStream
 require 'grape/validations/validators/all_or_none'
 require 'grape/validations/types'
 require 'grape/validations/validator_factory'
-
+require 'grape/railtie' if defined?(Rails::Railtie)
 require 'grape/version'

lib/grape/config.rb

@@ -5,6 +5,7 @@ module Config
     class Configuration
       ATTRIBUTES = %i[
         param_builder
+        on_unknown_validator
       ].freeze
 
       attr_accessor(*ATTRIBUTES)
@@ -15,6 +16,7 @@ def initialize
 
       def reset
         self.param_builder = Grape::Extensions::ActiveSupport::HashWithIndifferentAccess::ParamBuilder
+        self.on_unknown_validator = []
       end
     end
 

lib/grape/railtie.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Grape
+  class Railtie < Rails::Railtie
+    if Rails.version.to_f >= 6.0
+      initializer 'grape, setup zeitwerk loader for custom validators' do |_app|
+        Grape.config.on_unknown_validator << method(:on_grape_unknown_validator) if Rails.autoloaders.zeitwerk_enabled?
+      end
+    end
+
+    def on_grape_unknown_validator(name)
+      validator = ::Grape::Validations::Validators.const_get(name.camelize)
+
+      unless Rails.application.config.eager_load
+        # support reloading validators in development
+        Rails.autoloaders.main.on_unload(validator.to_s) do
+          ::Grape::Validations.deregister_validator(name)
+        end
+      end
+
+      validator
+    rescue NameError
+      nil
+    end
+  end
+end

lib/grape/validations/params_scope.rb

@@ -431,7 +431,7 @@ def check_incompatible_option_values(default, values, except_values, excepts)
       end
 
       def validate(type, options, attrs, doc_attrs, opts)
-        validator_class = Validations.validators[type.to_s]
+        validator_class = find_validator_class(type.to_s)
 
         raise Grape::Exceptions::UnknownValidator.new(type) unless validator_class
 
@@ -497,6 +497,14 @@ def document_attribute(attrs, doc_attrs)
         full_attrs = attrs.collect { |name| { name: name, full_name: full_name(name) } }
         @api.document_attribute(full_attrs, doc_attrs)
       end
+
+      def find_validator_class(name)
+        Validations.validators[name] ||
+          ::Grape.config.on_unknown_validator.find do |callback|
+            result = callback.call(name)
+            break result if result
+          end
+      end
     end
   end
 end

spec/grape/validations/params_scope_spec.rb

@@ -1188,4 +1188,41 @@ def initialize(value)
       end
     end
   end
+
+  context 'with unknown validator' do
+    it 'raises an error' do
+      expect do
+        subject.params do
+          optional :id, unknown: true
+        end
+      end.to raise_error(Grape::Exceptions::UnknownValidator)
+    end
+
+    context 'with a set callback' do
+      before do
+        Grape.config.on_unknown_validator << lambda { |_validator_name|
+          Class.new(Grape::Validations::Validators::Base) do
+            def validate_param!(attr_name, params)
+              params[attr_name] = 'custom_validator_implementation'
+            end
+          end
+        }
+      end
+
+      after do
+        Grape.config.on_unknown_validator.clear
+      end
+
+      it 'calls the callback' do
+        subject.params do
+          optional :id, unknown: true
+        end
+        subject.get('test') { params[:id] }
+
+        get 'test', id: 'test_validator'
+        expect(last_response.status).to eq(200)
+        expect(last_response.body).to eq('custom_validator_implementation')
+      end
+    end
+  end
 end