Fix for given block issues (#1433)

Move should_validate? check to validator base class so it gets
called for all validators.  This replaces the custom code in
allow_blank, and adds it to validators where it didn't previously
get called (like coerce).

Author: Joe Faber

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 #### Fixes
 
+* [#1498](https://github.com/ruby-grape/grape/pull/1498): Skip validations in inactive given blocks - [@jlfaber](https://github.com/jlfaber).
 * [#1479](https://github.com/ruby-grape/grape/pull/1479): Support inserting middleware before/after anonymous classes in the middleware stack - [@rosa](https://github.com/rosa).
 * [#1488](https://github.com/ruby-grape/grape/pull/1488): Ensure calling before filters when receiving OPTIONS request - [@namusyaka](https://github.com/namusyaka), [@jlfaber](https://github.com/jlfaber).
 * [#1493](https://github.com/ruby-grape/grape/pull/1493): Coercion and lambda fails params validation - [@jonmchan](https://github.com/jonmchan).

lib/grape/validations/validators/allow_blank.rb

@@ -7,19 +7,6 @@ def validate_param!(attr_name, params)
         value = params[attr_name]
         value = value.strip if value.respond_to?(:strip)
 
-        key_exists = params.key?(attr_name)
-
-        should_validate = if @scope.root?
-                            # root scope. validate if it's a required param. if it's optional, validate only if key exists in hash
-                            @required || key_exists
-                          else # nested scope
-                            (@required && params.present?) ||
-                              # optional param but key inside scoping element exists
-                              (!@required && params.key?(attr_name))
-                          end
-
-        return unless should_validate
-
         return if false == value || value.present?
 
         raise Grape::Exceptions::Validation, params: [@scope.full_name(attr_name)], message: message(:blank)

lib/grape/validations/validators/base.rb

@@ -24,6 +24,7 @@ def initialize(attrs, options, required, scope)
       # @raise [Grape::Exceptions::Validation] if validation failed
       # @return [void]
       def validate(request)
+        return unless @scope.should_validate?(request.params)
         validate!(request.params)
       end
 

lib/grape/validations/validators/default.rb

@@ -18,8 +18,6 @@ def validate_param!(attr_name, params)
       end
 
       def validate!(params)
-        return unless @scope.should_validate?(params)
-
         attrs = AttributesIterator.new(self, @scope, params)
         attrs.each do |resource_params, attr_name|
           if resource_params.is_a?(Hash) && resource_params[attr_name].nil?

lib/grape/validations/validators/presence.rb

@@ -1,11 +1,6 @@
 module Grape
   module Validations
     class PresenceValidator < Base
-      def validate!(params)
-        return unless @scope.should_validate?(params)
-        super
-      end
-
       def validate_param!(attr_name, params)
         return if params.respond_to?(:key?) && params.key?(attr_name)
         raise Grape::Exceptions::Validation, params: [@scope.full_name(attr_name)], message: message(:presence)