rework to satisfy usage of validation_contract

config.gemspec

@@ -27,7 +27,7 @@ Donate: \e[34mhttps://opencollective.com/rubyconfig/donate\e[0m\n"
 
   s.add_dependency 'deep_merge', '~> 1.2', '>= 1.2.1'
 
-  s.add_development_dependency 'dry-validation', *Config::DRY_VALIDATION_REQUIREMENTS
+  s.add_development_dependency 'dry-validation', *Config::DryValidationRequirements::VERSIONS
   s.add_development_dependency 'rake', '~> 12.0', '>= 12.0.0'
 
   # Testing

lib/config/dry_validation_requirements.rb

@@ -1,5 +1,27 @@
 # frozen_string_literal: true
 
 module Config
-  DRY_VALIDATION_REQUIREMENTS = ['~> 1.0', '>= 1.0.0'].freeze
+  module DryValidationRequirements
+    VERSIONS = ['~> 1.0', '>= 1.0.0'].freeze
+
+    def self.load_dry_validation!
+      return if defined?(@load_dry_validation)
+
+      begin
+        require 'dry/validation/version'
+        version = Gem::Version.new(Dry::Validation::VERSION)
+        unless VERSIONS.all? { |req| Gem::Requirement.new(req).satisfied_by?(version) }
+          raise LoadError
+        end
+      rescue LoadError
+        raise ::Config::Error, 'Could not find a dry-validation version' \
+          ' matching requirements' \
+          " (#{VERSIONS.map(&:inspect) * ','})"
+      end
+
+      require 'dry/validation'
+      @load_dry_validation = true
+      nil
+    end
+  end
 end

lib/config/validation/schema.rb

@@ -11,18 +11,8 @@ def schema=(value)
 
       def schema(&block)
         if block_given?
-          begin
-            require 'dry/validation/version'
-            version = Gem::Version.new(Dry::Validation::VERSION)
-            unless ::Config::DRY_VALIDATION_REQUIREMENTS.all? { |req| Gem::Requirement.new(req).satisfied_by?(version) }
-              raise LoadError
-            end
-          rescue LoadError
-            raise ::Config::Error, 'Could not find a dry-validation version matching requirements' \
-              " (#{::Config::DRY_VALIDATION_REQUIREMENTS.map(&:inspect) * ','})"
-          end
           # Delay require until optional schema validation is requested
-          require 'dry-validation'
+          Config::DryValidationRequirements.load_dry_validation!
           @schema = Dry::Schema.define(&block)
         else
           @schema

lib/config/validation/validate.rb

@@ -4,6 +4,10 @@ module Config
   module Validation
     module Validate
       def validate!
+        return unless Config.validation_contract || Config.schema
+
+        Config::DryValidationRequirements.load_dry_validation!
+
         validate_using!(Config.validation_contract)
         validate_using!(Config.schema)
       end