MONGOID-5843 Ensure BSON::Decimal128 is considered to be numeric (#5961)

* RUBY-5843 Ensure BSON::Decimal128 is considered to be numeric

* bump drivers-evergreen-tools

* let's see how this version of drivers-evergreen-tools does

* Revert "let's see how this version of drivers-evergreen-tools does"

This reverts commit 243fc49.

* don't try to run `rails new` on rails < 7.1

concurrent-ruby gem removed a dependency on logger, which
rails assumed was there. Installing those versions of Rails
will install a too-new version of concurrent-ruby, which causes
`rails new` to fail because it can't resolve Logger.

Author: jamis

.mod/drivers-evergreen-tools

@@ -6,6 +6,7 @@
 require "mongoid/validatable/associated"
 require "mongoid/validatable/format"
 require "mongoid/validatable/length"
+require "mongoid/validatable/numericality"
 require "mongoid/validatable/queryable"
 require "mongoid/validatable/presence"
 require "mongoid/validatable/uniqueness"

lib/mongoid/validatable.rb

@@ -89,6 +89,21 @@ def validates_length_of(*args)
       def validates_presence_of(*args)
         validates_with(PresenceValidator, _merge_attributes(args))
       end
+
+      # Validates whether or not a field contains a numeric value.
+      #
+      # @example
+      #   class Person
+      #     include Mongoid::Document
+      #     field :cost
+      #
+      #     validates_numericality_of :cost
+      #   end
+      #
+      # @param [ Object... ] *args The names of the field(s) to validate.
+      def validates_numericality_of(*args)
+        validates_with(NumericalityValidator, _merge_attributes(args))
+      end
     end
   end
 end

lib/mongoid/validatable/macros.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Mongoid
+  module Validatable
+    # A specialization of the ActiveModel numericality validator, which adds
+    # logic to recognize and accept BSON::Decimal128 as a number.
+    class NumericalityValidator < ActiveModel::Validations::NumericalityValidator
+      private
+
+      # Ensure that BSON::Decimal128 is treated as a BigDecimal during the
+      # validation step.
+      def prepare_value_for_validation(value, record, attr_name)
+        result = super
+
+        result.is_a?(BSON::Decimal128) ? result.to_big_decimal : result
+      end
+    end
+  end
+end

lib/mongoid/validatable/numericality.rb

@@ -123,6 +123,12 @@ def prepare_new_rails_app(name)
   end
 
   context 'new application - rails' do
+    before(:all) do
+      if SpecConfig.instance.rails_version < '7.1'
+        skip '`rails new` with rails < 7.1 fails because modern concurrent-ruby removed logger dependency'
+      end
+    end
+
     it 'creates' do
       prepare_new_rails_app 'mongoid-test' do
         check_call(%w(rails g model post), env: clean_env)

spec/integration/app_spec.rb

@@ -29,5 +29,21 @@ class TestModel
         expect(model).to_not be_valid
       end
     end
+
+    context 'when the value is numeric' do
+      let(:model) { TestModel.new(amount: '15.0') }
+
+      it 'returns true' do
+        expect(model).to be_valid
+      end
+    end
+
+    context 'when the value is a BSON::Decimal128' do
+      let(:model) { TestModel.new(amount: BSON::Decimal128.new('15.0')) }
+
+      it 'returns true' do
+        expect(model).to be_valid
+      end
+    end
   end
 end