Ticket #39692: 39692.6.diff

src/wp-includes/class-wp-customize-nav-menus.php

@@ -29 +29 @@
         /**
          * Previewed Menus.
          *
+         * @todo This is unused and can be removed.
+         *
          * @since 4.3.0
          * @var array
          */
         public $previewed_menus;
 
         /**
+         * Original nav menu locations before the theme was switched.
+         *
+         * @since 4.9.0
+         * @var array
+         */
+        protected $original_nav_menu_locations;
+
+        /**
          * Constructor.
          *
          * @since 4.3.0
@@ -42 +52 @@
          * @param object $manager An instance of the WP_Customize_Manager class.
          */
         public function __construct( $manager ) {
-                $this->previewed_menus = array();
-                $this->manager         = $manager;
+                $this->previewed_menus = array(); // @todo This is unused and can be removed.
+                $this->manager = $manager;
+                $this->original_nav_menu_locations = get_nav_menu_locations();
 
                 // See https://github.com/xwp/wp-customize-snapshots/blob/962586659688a5b1fd9ae93618b7ce2d4e7a421c/php/class-customize-snapshot-manager.php#L469-L499
                 add_action( 'customize_register', array( $this, 'customize_register' ), 11 );
@@ -582 +593 @@
                         $choices[ $menu->term_id ] = wp_html_excerpt( $menu->name, 40, '…' );
                 }
 
+                // Attempt to re-map the nav menu location assignments when previewing a theme switch.
+                $remapped_nav_menu_locations = array();
+                if ( ! $this->manager->is_theme_active() ) {
+                        $remapped_nav_menu_locations = wp_get_remapped_nav_menu_locations( get_nav_menu_locations(), $this->original_nav_menu_locations );
+                }
+
                 foreach ( $locations as $location => $description ) {
                         $setting_id = "nav_menu_locations[{$location}]";
 
@@ -600 +617 @@
                                 ) );
                         }
 
+                        // Override the assigned nav menu location if remapped during previewed theme switch.
+                        if ( isset( $remapped_nav_menu_locations[ $location ] ) ) {
+                                $this->manager->set_post_value( $setting_id, $remapped_nav_menu_locations[ $location ] );
+                        }
+
                         $this->manager->add_control( new WP_Customize_Nav_Menu_Location_Control( $this->manager, $setting_id, array(
                                 'label'       => $description,
                                 'location_id' => $location,

src/wp-includes/default-filters.php

@@ -262 +262 @@
 add_action( 'template_redirect',   'wp_shortlink_header',             11, 0 );
 add_action( 'wp_print_footer_scripts', '_wp_footer_scripts'                 );
 add_action( 'init',                'check_theme_switched',            99    );
+add_action( 'after_switch_theme',  '_wp_menus_changed'                      );
 add_action( 'after_switch_theme',  '_wp_sidebars_changed'                   );
 add_action( 'wp_print_styles',     'print_emoji_styles'                     );
 

src/wp-includes/nav-menu.php

@@ -1026 +1026 @@
         }
         add_action( 'delete_post', '_wp_delete_customize_changeset_dependent_auto_drafts' );
 }
+
+/**
+ * Handle menu config after theme change.
+ *
+ * @access private
+ * @since 4.9.0
+ */
+function _wp_menus_changed() {
+        $old_nav_menu_locations = get_option( 'theme_switch_menu_locations', array() );
+        $new_nav_menu_locations = get_nav_menu_locations();
+        $remapped_nav_menu_locations = wp_get_remapped_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations );
+        set_theme_mod( 'nav_menu_locations', $remapped_nav_menu_locations );
+        delete_option( 'theme_switch_menu_locations' );
+}
+
+/**
+ * Re-maps nav menu location assignments according to previous location assignments (in a different theme).
+ *
+ * @since 4.9.0
+ *
+ * @param array $new_nav_menu_locations New nav menu locations assignments.
+ * @param array $old_nav_menu_locations Old nav menu locations assignments.
+ * @return array Nav menus remapped to new nav menu locations.
+ */
+function wp_get_remapped_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations ) {
+        $registered_nav_menus = get_registered_nav_menus();
+
+        // Short-circuit if there are no old nav menu location assignments to map.
+        if ( empty( $old_nav_menu_locations ) ) {
+                return $new_nav_menu_locations;
+        }
+
+        // If old and new theme have just one location, map it and we're done.
+        if ( 1 === count( $old_nav_menu_locations ) && 1 === count( $registered_nav_menus ) ) {
+                $new_nav_menu_locations[ key( $registered_nav_menus ) ] = array_pop( $old_nav_menu_locations );
+                return $new_nav_menu_locations;
+        }
+
+        $old_locations = array_keys( $old_nav_menu_locations );
+
+        // Map locations with the same slug.
+        foreach ( $registered_nav_menus as $location => $name ) {
+                if ( in_array( $location, $old_locations, true ) ) {
+                        $new_nav_menu_locations[ $location ] = $old_nav_menu_locations[ $location ];
+                        unset( $old_nav_menu_locations[ $location ] );
+                }
+        }
+
+        // If there are no old nav menu locations left, then we're done.
+        if ( empty( $old_nav_menu_locations ) ) {
+                return $new_nav_menu_locations;
+        }
+
+        /*
+         * If old and new theme both have locations that contain phrases
+         * from within the same group, make an educated guess and map it.
+         */
+        $common_slug_groups = array(
+                array( 'header', 'main', 'navigation', 'primary', 'top' ),
+                array( 'bottom', 'footer', 'secondary', 'subsidiary' ),
+                array( 'social' ),
+                // TODO: Find a second slug or remove, since locations with same slug are already mapped.
+        );
+
+        // Go through each group...
+        foreach ( $common_slug_groups as $slug_group ) {
+
+                // ...and see if any of these slugs...
+                foreach ( $slug_group as $slug ) {
+
+                        // ...and any of the new menu locations...
+                        foreach ( $registered_nav_menus as $new_location => $name ) {
+
+                                // ...actually match!
+                                if ( false === stripos( $new_location, $slug ) && false === stripos( $slug, $new_location ) ) {
+                                        continue;
+                                }
+
+                                // Then see if any of the old locations...
+                                foreach ( $old_nav_menu_locations as $location => $menu_id ) {
+
+                                        // ...match a slug in the same group.
+                                        foreach ( $slug_group as $slug ) {
+
+                                                // But skip if the location and slug don't match.
+                                                if ( false === stripos( $location, $slug ) && false === stripos( $slug, $location ) ) {
+                                                        continue;
+                                                }
+
+                                                // Make sure this location wasn't mapped and removed previously.
+                                                if ( ! empty( $old_nav_menu_locations[ $location ] ) ) {
+
+                                                        // We have a match that can be mapped!
+                                                        $new_nav_menu_locations[ $new_location ] = $old_nav_menu_locations[ $location ];
+
+                                                        // Remove the mapped location so it can't be mapped again.
+                                                        unset( $old_nav_menu_locations[ $location ] );
+
+                                                        // Go back and check the next new menu location.
+                                                        continue 3;
+                                                }
+                                        } // endforeach ( $slug_group as $slug )
+                                } // endforeach ( $old_nav_menu_locations as $location => $menu_id )
+                        } // endforeach foreach ( $registered_nav_menus as $new_location => $name )
+                } // endforeach ( $slug_group as $slug )
+        } // endforeach ( $common_slug_groups as $slug_group )
+
+        return $new_nav_menu_locations;
+}

src/wp-includes/theme.php

@@ -691 +691 @@
         }
 
         $nav_menu_locations = get_theme_mod( 'nav_menu_locations' );
+        add_option( 'theme_switch_menu_locations', $nav_menu_locations );
 
         if ( func_num_args() > 1 ) {
                 $stylesheet = func_get_arg( 1 );
@@ -731 +732 @@
                 if ( 'wp_ajax_customize_save' === current_action() ) {
                         remove_theme_mod( 'sidebars_widgets' );
                 }
-
-                if ( ! empty( $nav_menu_locations ) ) {
-                        $nav_mods = get_theme_mod( 'nav_menu_locations' );
-                        if ( empty( $nav_mods ) ) {
-                                set_theme_mod( 'nav_menu_locations', $nav_menu_locations );
-                        }
-                }
         }
 
         update_option( 'theme_switched', $old_theme->get_stylesheet() );

new file tests/phpunit/tests/menu/nav-menu.php

@@ +1 @@
+<?php
+
+/**
+ * @group navmenus
+ */
+class Tests_Nav_Menu_Theme_Change extends WP_UnitTestCase {
+
+        /**
+         * Set up.
+         */
+        function setUp() {
+                parent::setUp();
+
+                // Unregister all nav menu locations.
+                foreach ( array_keys( get_registered_nav_menus() ) as $location ) {
+                        unregister_nav_menu( $location );
+                }
+
+                register_nav_menus( array(
+                        'primary' => 'Primary',
+                ) );
+        }
+
+        /**
+         * Two themes with one location each should just map.
+         */
+        function test_one_location_each() {
+                $old_nav_menu_locations = array(
+                        'unique-slug' => 1,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+
+                _wp_menus_changed();
+                $this->assertEqualSets( $old_nav_menu_locations, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * Locations with the same name should map.
+         */
+        function test_locations_with_same_slug() {
+                $old_nav_menu_locations = array(
+                        'primary' => 1,
+                        'secondary' => 2,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                register_nav_menu( 'secondary', 'Secondary' );
+
+                _wp_menus_changed();
+                $this->assertEqualSets( $old_nav_menu_locations, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * If the new theme was previously active, we should fall back to that data.
+         */
+        function test_new_theme_previously_active() {
+                $old_nav_menu_locations = array(
+                        'primary' => 3,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                $previous_locations = array(
+                        'primary' => 1,
+                        'secondary' => 2,
+                );
+                set_theme_mod( 'nav_menu_locations', $previous_locations );
+
+                _wp_menus_changed();
+                $expected = array_merge( $previous_locations, $old_nav_menu_locations );
+                $this->assertEqualSets( $expected, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * Make educated guesses on theme locations.
+         */
+        function test_location_guessing() {
+                $old_nav_menu_locations = array(
+                        'header' => 1,
+                        'footer' => 2,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                register_nav_menu( 'secondary', 'Secondary' );
+
+                _wp_menus_changed();
+                $expected = array(
+                        'primary' => 1,
+                        'secondary' => 2,
+                );
+                $this->assertEqualSets( $expected, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * Make sure two locations that fall in the same group don't get the same menu assigned.
+         */
+        function test_location_guessing_one_menu_per_group() {
+                $old_nav_menu_locations = array(
+                        'top-menu' => 1,
+                        'secondary' => 2,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                register_nav_menu( 'main', 'Main' );
+
+                _wp_menus_changed();
+                $expected = array(
+                        'main' => 1,
+                );
+                $this->assertEqualSets( $expected, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * Make sure two locations that fall in the same group get menus assigned from the same group.
+         */
+        function test_location_guessing_one_menu_per_location() {
+                $old_nav_menu_locations = array(
+                        'navigation-menu' => 1,
+                        'top-menu' => 2,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                register_nav_menu( 'main', 'Main' );
+
+                _wp_menus_changed();
+                $expected = array(
+                        'main' => 1,
+                        'primary' => 2,
+                );
+                $this->assertEqualSets( $expected, get_theme_mod( 'nav_menu_locations' ) );
+        }
+
+        /**
+         * Technically possible to register menu locations numerically.
+         */
+        function test_numerical_locations() {
+                $old_nav_menu_locations = array(
+                        'main' => 1,
+                        'secondary' => 2,
+                        'tertiary' => 3,
+                );
+                update_option( 'theme_switch_menu_locations', $old_nav_menu_locations );
+                register_nav_menu( 1 , 'First' );
+
+                _wp_menus_changed();
+                $expected = array(
+                        'primary' => 1,
+                );
+                $this->assertEqualSets( $expected, get_theme_mod( 'nav_menu_locations' ) );
+        }
+}