From 0c676f363b19fb1d1196c263e363f42193081b86 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9?= <583546+oandregal@users.noreply.github.com>
Date: Tue, 11 Oct 2022 19:20:36 +0200
Subject: [PATCH] get_merged_data: start from an existing theme.json

get_merged_data is now a hotpath that is called many times.
By improving small things that are repeated multiple times
we get more performance wins.

Instead of starting with an empty WP_Theme_JSON and call the merge operation
we start by using the existing WP_Theme_JSON from core.

This reduces from 402 to 326 the number of calls of the low-level
WP_Theme_JSON->merge method.
---
 src/wp-includes/class-wp-theme-json-resolver.php | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/wp-includes/class-wp-theme-json-resolver.php b/src/wp-includes/class-wp-theme-json-resolver.php
index 993543a55b2b7..18b997561cf05 100644
--- a/src/wp-includes/class-wp-theme-json-resolver.php
+++ b/src/wp-includes/class-wp-theme-json-resolver.php
@@ -548,8 +548,7 @@ public static function get_merged_data( $origin = 'custom' ) {
 			_deprecated_argument( __FUNCTION__, '5.9.0' );
 		}
 
-		$result = new WP_Theme_JSON();
-		$result->merge( static::get_core_data() );
+		$result = static::get_core_data();
 		$result->merge( static::get_block_data() );
 		$result->merge( static::get_theme_data() );