From fe3721e8a210490ec09980737c621aa213b526df Mon Sep 17 00:00:00 2001
From: Dave Long <dave@longwaveconsulting.com>
Date: Fri, 10 May 2024 09:57:45 +0100
Subject: [PATCH] Issue #3425692 by msandoval, bember, KarimB, Amirez, Lenenba,
 joachim, mradcliffe, julieelman, Farnoosh: development.services.yml should
 document that parameters are only shallow-merged

---
 core/assets/scaffold/files/development.services.yml | 10 ++++++++++
 sites/development.services.yml                      | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/core/assets/scaffold/files/development.services.yml b/core/assets/scaffold/files/development.services.yml
index d2857c66f8a5..c02d3ff941f6 100644
--- a/core/assets/scaffold/files/development.services.yml
+++ b/core/assets/scaffold/files/development.services.yml
@@ -1,7 +1,17 @@
 # Local development services.
 #
+# The development.services.yml file allows the developer to override
+# container parameters for debugging.
+#
 # To activate this feature, follow the instructions at the top of the
 # 'example.settings.local.php' file, which sits next to this file.
+#
+# Be aware that in Drupal's configuration system, all the files that
+# provide container definitions are merged using a shallow merge approach
+# within \Drupal\Core\DependencyInjection\YamlFileLoader.
+# This means that if you want to override any value of a parameter, the
+# whole parameter array needs to be copied from
+# sites/default/default.services.yml or from core/core.services.yml file.
 parameters:
   http.response.debug_cacheability_headers: true
 services:
diff --git a/sites/development.services.yml b/sites/development.services.yml
index d2857c66f8a5..c02d3ff941f6 100644
--- a/sites/development.services.yml
+++ b/sites/development.services.yml
@@ -1,7 +1,17 @@
 # Local development services.
 #
+# The development.services.yml file allows the developer to override
+# container parameters for debugging.
+#
 # To activate this feature, follow the instructions at the top of the
 # 'example.settings.local.php' file, which sits next to this file.
+#
+# Be aware that in Drupal's configuration system, all the files that
+# provide container definitions are merged using a shallow merge approach
+# within \Drupal\Core\DependencyInjection\YamlFileLoader.
+# This means that if you want to override any value of a parameter, the
+# whole parameter array needs to be copied from
+# sites/default/default.services.yml or from core/core.services.yml file.
 parameters:
   http.response.debug_cacheability_headers: true
 services:
-- 
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