From 4a0b7a50eac1e5da90d6f2527f3aa023c1094741 Mon Sep 17 00:00:00 2001
From: Jonathan Hefner <jonathan@hefner.pro>
Date: Mon, 2 Oct 2023 12:39:59 -0500
Subject: [PATCH] Avoid defining Hash#deep_merge and #deep_merge!

`config` uses `DeepMerge.deep_merge!` instead of `Hash#deep_merge!`, so
monkey patching `Hash` is unnecessary.  Furthermore, DeepMerge's `Hash`
monkey patch is not compatible with Rails 7.1 (see [rails#49457][]).

This commit changes `require 'deep_merge'` to `require 'deep_merge/core'`
so that DeepMerge's `Hash` monkey patch is no longer loaded.  Users who
rely on the monkey patch can load it manually via
`require 'deep_merge/deep_merge_hash'`.

Closes #314.

[rails#49457]: https://github.com/rails/rails/issues/49457
---
 CHANGELOG.md  | 6 ++++++
 lib/config.rb | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b7dc03f0..b2a3e8a8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## 5.0.0
+
+### BREAKING CHANGES
+
+* `config` no longer loads `deep_merge`'s monkey patch for `Hash#deep_merge` and `Hash#deep_merge!` ([#342](https://github.com/rubyconfig/config/pull/342)). If you rely on those methods and are not using Rails / Active Support, you can load the monkey patch via `require 'deep_merge/deep_merge_hash'`.
+
 ## 4.2.1
 
 ### Bug fixes
diff --git a/lib/config.rb b/lib/config.rb
index 4713f8ba..5bd5ae11 100644
--- a/lib/config.rb
+++ b/lib/config.rb
@@ -6,7 +6,7 @@
 require 'config/sources/hash_source'
 require 'config/sources/env_source'
 require 'config/validation/schema'
-require 'deep_merge'
+require 'deep_merge/core'
 
 module Config
   extend Config::Validation::Schema