From 8059b362e83b980be06a32098a0f7168fc939de9 Mon Sep 17 00:00:00 2001
From: Dominik Schilling <dominikschilling+git@gmail.com>
Date: Sat, 27 Jul 2019 12:44:56 +0000
Subject: [PATCH] I18N: Add support for custom `WP_PLUGIN_URL` in
 `load_script_textdomain()`.

Plugins may not be on the same host/path as the rest of the content. To support loading translations for this setup check if the script source matches `plugins_url()`.
Also fixes an undefined index notice when a custom content URL has no path.

Props odminstudios, ocean90.
Fixes #46336, #46387.
Built from https://develop.svn.wordpress.org/trunk@45685


git-svn-id: http://core.svn.wordpress.org/trunk@45496 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/l10n.php    | 29 ++++++++++++++++++++++++++---
 wp-includes/version.php |  2 +-
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/wp-includes/l10n.php b/wp-includes/l10n.php
index 4bcdc4fc4e..bd0110d780 100644
--- a/wp-includes/l10n.php
+++ b/wp-includes/l10n.php
@@ -948,20 +948,43 @@ function load_script_textdomain( $handle, $domain = 'default', $path = null ) {
 
 	$src_url     = wp_parse_url( $src );
 	$content_url = wp_parse_url( content_url() );
+	$plugins_url = wp_parse_url( plugins_url() );
 	$site_url    = wp_parse_url( site_url() );
 
 	// If the host is the same or it's a relative URL.
 	if (
-		strpos( $src_url['path'], $content_url['path'] ) === 0 &&
+		( ! isset( $content_url['path'] ) || strpos( $src_url['path'], $content_url['path'] ) === 0 ) &&
 		( ! isset( $src_url['host'] ) || $src_url['host'] === $content_url['host'] )
 	) {
 		// Make the src relative the specific plugin or theme.
-		$relative = trim( substr( $src_url['path'], strlen( $content_url['path'] ) ), '/' );
+		if ( isset( $content_url['path'] ) ) {
+			$relative = substr( $src_url['path'], strlen( $content_url['path'] ) );
+		} else {
+			$relative = $src_url['path'];
+		}
+		$relative = trim( $relative, '/' );
 		$relative = explode( '/', $relative );
 
 		$languages_path = WP_LANG_DIR . '/' . $relative[0];
 
-		$relative = array_slice( $relative, 2 );
+		$relative = array_slice( $relative, 2 ); // Remove plugins/<plugin name> or themes/<theme name>.
+		$relative = implode( '/', $relative );
+	} elseif (
+		( ! isset( $plugins_url['path'] ) || strpos( $src_url['path'], $plugins_url['path'] ) === 0 ) &&
+		( ! isset( $src_url['host'] ) || $src_url['host'] === $plugins_url['host'] )
+	) {
+		// Make the src relative the specific plugin.
+		if ( isset( $plugins_url['path'] ) ) {
+			$relative = substr( $src_url['path'], strlen( $plugins_url['path'] ) );
+		} else {
+			$relative = $src_url['path'];
+		}
+		$relative = trim( $relative, '/' );
+		$relative = explode( '/', $relative );
+
+		$languages_path = WP_LANG_DIR . '/plugins';
+
+		$relative = array_slice( $relative, 1 ); // Remove <plugin name>.
 		$relative = implode( '/', $relative );
 	} elseif ( ! isset( $src_url['host'] ) || $src_url['host'] === $site_url['host'] ) {
 		if ( ! isset( $site_url['path'] ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index c6952c572c..b7dd8923d8 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.3-alpha-45684';
+$wp_version = '5.3-alpha-45685';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.