From f66aefa71e5996acb1519b23600828b352b9cd0c Mon Sep 17 00:00:00 2001
From: Jonathan Desrosiers <359867+desrosj@users.noreply.github.com>
Date: Mon, 9 Mar 2026 21:08:56 -0400
Subject: [PATCH] Account `IS_WORDPRESS_CORE` is set.

In #76038, code was added to exclude experimental pages when building for WordPress Core.

The code merged in #75844 did not adjust this code to detect the environment variable `IS_WORDPRESS_CORE` before `npm_package_config_IS_WORDPRESS_CORE`.
---
 packages/wp-build/lib/build.mjs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/wp-build/lib/build.mjs b/packages/wp-build/lib/build.mjs
index c5ad3cbea9038b..910bc0fb589925 100755
--- a/packages/wp-build/lib/build.mjs
+++ b/packages/wp-build/lib/build.mjs
@@ -1801,9 +1801,9 @@ async function buildAll( baseUrlExpression ) {
 	} );
 
 	// When building for WordPress Core, exclude experimental pages.
-	const isCoreBuild = Boolean(
-		process.env.npm_package_config_IS_WORDPRESS_CORE
-	);
+	const isCoreBuild =
+		boolConfigVal( process.env.IS_WORDPRESS_CORE ) ||
+		boolConfigVal( process.env.npm_package_config_IS_WORDPRESS_CORE );
 	const activePages = isCoreBuild
 		? normalizedPages.filter( ( page ) => ! page.experimental )
 		: normalizedPages;