Fix ordering issues between as: and default: validations

CHANGELOG.md

@@ -6,7 +6,8 @@
 
 #### Fixes
 
-* [#2176](https://github.com/ruby-grape/grape/pull/2176): Fixes issue-2175 - options call failing if matching all routes - [@myxoh](https://github.com/myxoh).
+* [#2176](https://github.com/ruby-grape/grape/pull/2176): Fix: OPTIONS fails if matching all routes - [@myxoh](https://github.com/myxoh).
+* [#2177](https://github.com/ruby-grape/grape/pull/2177): Fix: `default` validator fails if preceded by `as` validator - [@Catsuko](https://github.com/Catsuko).
 * Your contribution here.
 ### 1.5.3 (2021/03/07)
 

lib/grape/validations/params_scope.rb

@@ -283,16 +283,15 @@ def validates(attrs, validations)
 
         doc_attrs[:documentation] = validations.delete(:documentation) if validations.key?(:documentation)
 
-        full_attrs = attrs.collect { |name| { name: name, full_name: full_name(name) } }
-        @api.document_attribute(full_attrs, doc_attrs)
+        document_attribute(attrs, doc_attrs)
 
         opts = derive_validator_options(validations)
 
+        order_specific_validations = Set[:as]
+
         # Validate for presence before any other validators
-        if validations.key?(:presence) && validations[:presence]
-          validate('presence', validations[:presence], attrs, doc_attrs, opts)
-          validations.delete(:presence)
-          validations.delete(:message) if validations.key?(:message)
+        validates_presence(validations, attrs, doc_attrs, opts) do |validation_type|
+          order_specific_validations << validation_type
         end
 
         # Before we run the rest of the validators, let's handle
@@ -301,8 +300,13 @@ def validates(attrs, validations)
         coerce_type validations, attrs, doc_attrs, opts
 
         validations.each do |type, options|
+          next if order_specific_validations.include?(type)
           validate(type, options, attrs, doc_attrs, opts)
         end
+
+        # Apply as validator last so other validations are applied to
+        # renamed param
+        validate(:as, validations[:as], attrs, doc_attrs, opts) if validations.key?(:as)
       end
 
       # Validate and comprehend the +:type+, +:types+, and +:coerce_with+
@@ -464,6 +468,18 @@ def derive_validator_options(validations)
           fail_fast:   validations.delete(:fail_fast) || false
         }
       end
+
+      def validates_presence(validations, attrs, doc_attrs, opts)
+        return unless validations.key?(:presence) && validations[:presence]
+        validate(:presence, validations[:presence], attrs, doc_attrs, opts)
+        yield :presence
+        yield :message if validations.key?(:message)
+      end
+
+      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
     end
   end
 end

spec/grape/validations/params_scope_spec.rb

@@ -180,6 +180,28 @@ def initialize(value)
       expect(last_response.status).to eq(200)
       expect(last_response.body).to eq('{"baz":{"qux":"any"}}')
     end
+
+    it 'renaming can be defined before default' do
+      subject.params do
+        optional :foo, as: :bar, default: 'before'
+      end
+      subject.get('/rename-before-default') { params[:bar] }
+      get '/rename-before-default'
+
+      expect(last_response.status).to eq(200)
+      expect(last_response.body).to eq('before')
+    end
+
+    it 'renaming can be defined after default' do
+      subject.params do
+        optional :foo, default: 'after', as: :bar
+      end
+      subject.get('/rename-after-default') { params[:bar] }
+      get '/rename-after-default'
+
+      expect(last_response.status).to eq(200)
+      expect(last_response.body).to eq('after')
+    end
   end
 
   context 'array without coerce type explicitly given' do