From 45ae318dd01c0a05b8e783798b25488ea6ba9c8b Mon Sep 17 00:00:00 2001
From: Johnny Shields <johnny.shields@gmail.com>
Date: Wed, 27 Jul 2022 00:00:01 +0900
Subject: [PATCH] MONGOID-5422 - Configuration DSL should not require an
 argument to its block (Rails parity) (#5367)

* MONGOID-5422 - Configuration DSL no longer requires an argument to its block

* More terse syntax

* Use config_override

* Update docs/release-notes/mongoid-8.1.txt

Co-authored-by: shields <shields@tablecheck.com>
Co-authored-by: Oleg Pudeyev <39304720+p-mongo@users.noreply.github.com>
---
 docs/release-notes/mongoid-8.1.txt | 25 ++++++++++++++++++
 lib/mongoid.rb                     | 14 ++++++++--
 lib/mongoid/config.rb              |  7 +++++
 spec/mongoid_spec.rb               | 42 +++++++++++++++++++++++-------
 4 files changed, 77 insertions(+), 11 deletions(-)

diff --git a/docs/release-notes/mongoid-8.1.txt b/docs/release-notes/mongoid-8.1.txt
index 211cb4de58..10c329af38 100644
--- a/docs/release-notes/mongoid-8.1.txt
+++ b/docs/release-notes/mongoid-8.1.txt
@@ -18,6 +18,31 @@ please consult GitHub releases for detailed release notes and JIRA for
 the complete list of issues fixed in each release, including bug fixes.
 
 
+Configuration DSL No Longer Requires an Argument to its Block
+-------------------------------------------------------------
+
+It is now possible to use ``Mongoid.configure`` without
+providing an argument to its block:
+
+.. code-block:: ruby
+
+  Mongoid.configure do
+    connect_to("mongoid_test")
+
+    # Use config method when assigning variables
+    config.preload_models = true
+
+Note that ``configure`` will continue to support a block argument.
+The following is equivalent to the above:
+
+.. code-block:: ruby
+
+  Mongoid.configure do |config|
+    config.connect_to("mongoid_test")
+
+    config.preload_models = true
+
+
 Added ``Mongoid::Criteria`` finder methods
 ------------------------------------------
 
diff --git a/lib/mongoid.rb b/lib/mongoid.rb
index 61191b9a34..22816bd9e2 100644
--- a/lib/mongoid.rb
+++ b/lib/mongoid.rb
@@ -58,9 +58,19 @@ module Mongoid
   #     }
   #   end
   #
+  # @example Using a block without an argument. Use `config` inside
+  #   the block to perform variable assignment.
+  #
+  #   Mongoid.configure do
+  #     connect_to("mongoid_test")
+  #
+  #     config.preload_models = true
+  #
   # @return [ Config ] The configuration object.
-  def configure
-    block_given? ? yield(Config) : Config
+  def configure(&block)
+    return Config unless block_given?
+
+    block.arity == 0 ? Config.instance_exec(&block) : yield(Config)
   end
 
   # Convenience method for getting the default client.
diff --git a/lib/mongoid/config.rb b/lib/mongoid/config.rb
index 0c22c96f86..6b3ad65f06 100644
--- a/lib/mongoid/config.rb
+++ b/lib/mongoid/config.rb
@@ -127,6 +127,13 @@ module Config
     # always return a Hash.
     option :legacy_attributes, default: false
 
+    # Returns the Config singleton, for use in the configure DSL.
+    #
+    # @return [ self ] The Config singleton.
+    def config
+      self
+    end
+
     # Has Mongoid been configured? This is checking that at least a valid
     # client config exists.
     #
diff --git a/spec/mongoid_spec.rb b/spec/mongoid_spec.rb
index 464f5f8b9f..5f25635594 100644
--- a/spec/mongoid_spec.rb
+++ b/spec/mongoid_spec.rb
@@ -13,22 +13,46 @@
       end
     end
 
-    context "when a block is supplied" do
+    context "when a block is given" do
+      config_override :preload_models, false
 
-      before do
-        Mongoid.configure do |config|
-          config.preload_models = true
+      context "with arity 0" do
+
+        before do
+          Mongoid.configure do
+            config.preload_models = true
+          end
+        end
+
+        it "sets the values on the config instance" do
+          expect(Mongoid.preload_models).to be true
         end
       end
 
-      after do
-        Mongoid.configure do |config|
-          config.preload_models = false
+      context "with arity 1" do
+
+        before do
+          Mongoid.configure do |config|
+            config.preload_models = true
+          end
+        end
+
+        it "sets the values on the config instance" do
+          expect(Mongoid.preload_models).to be true
         end
       end
 
-      it "sets the values on the config instance" do
-        expect(Mongoid.preload_models).to be true
+      context "with arity 2" do
+
+        before do
+          Mongoid.configure do |config, _other|
+            config.preload_models = true
+          end
+        end
+
+        it "sets the values on the config instance" do
+          expect(Mongoid.preload_models).to be true
+        end
       end
     end
   end