Ticket #39295: 39295.2.alt.diff

src/wp-includes/l10n.php

@@ -88 +88 @@
  *
  * @since 4.7.0
  *
+ * @global string $locale The current locale.
+ *
  * @param int|WP_User $user_id User's ID or a WP_User object. Defaults to current user.
  * @return string The locale of the user.
  */
 function get_user_locale( $user_id = 0 ) {
+        global $locale;
+
         $user = false;
         if ( 0 === $user_id && function_exists( 'wp_get_current_user' ) ) {
                 $user = wp_get_current_user();
@@ -101 +105 @@
                 $user = get_user_by( 'id', $user_id );
         }
 
-        if ( ! $user ) {
-                return get_locale();
+        if ( $user && $user->locale ) {
+                $user_locale = $user->locale;
+        } elseif ( ! doing_filter( 'locale' ) ) {
+                $user_locale = get_locale();
+        } else {
+                $user_locale = $locale;
         }
 
-        $locale = $user->locale;
-        return $locale ? $locale : get_locale();
+        return $user_locale;
 }
 
 /**

tests/phpunit/tests/l10n/getUserLocale.php

@@ -136 +136 @@
                 $user_locale = get_user_locale( 'string' );
                 $this->assertSame( get_locale(), $user_locale );
         }
+
+        /**
+         * @ticket 39295
+         */
+        public function test_get_user_locale_as_locale_filter_works_as_expected() {
+                wp_set_current_user( 0 );
+                switch_to_locale( 'de_DE');
+
+                $user_locale1 = get_user_locale();
+
+                add_filter( 'locale', 'get_user_locale' );
+
+                $user_locale2 = get_user_locale();
+
+                remove_filter( 'locale', 'get_user_locale' );
+
+                restore_current_locale();
+
+                $this->assertSame( 'de_DE', $user_locale1 );
+                $this->assertSame( 'en_US', $user_locale2 );
+        }
 }