Ticket #14877: 14877.2.diff

src/wp-admin/includes/meta-boxes.php

@@ -560 +560 @@
 }
 
 /**
+ * Display taxonomy assignment dropdown form.
+ *
+ * @since 4.7.0
+ *
+ * @param WP_Post $post Post object.
+ * @param array   $box {
+ *     Categories meta box arguments.
+ *
+ *     @type string   $id       Meta box 'id' attribute.
+ *     @type string   $title    Meta box title.
+ *     @type callable $callback Meta box display callback.
+ *     @type array    $args {
+ *         Extra meta box arguments.
+ *
+ *         @type string $taxonomy Taxonomy. Default 'category'.
+ *     }
+ * }
+ */
+function taxonomy_dropdown_meta_box( $post, $box ) {
+        $defaults = array( 'taxonomy' => 'category' );
+
+//// @TODO: Meta box title should be singular (probably),
+///         currently from edit-form-advanced you get $taxonomy->labels->name.
+///         Maybe it should be a new label?
+        if ( ! isset( $box['args'] ) || ! is_array( $box['args'] ) ) {
+                $args = array();
+        } else {
+                $args = $box['args'];
+        }
+
+        $r = wp_parse_args( $args, $defaults );
+        $tax_name = esc_attr( $r['taxonomy'] );
+        $taxonomy = get_taxonomy( $tax_name );
+
+        $input_name = ( $tax_name == 'category' ) ? 'post_category[]' : 'tax_input[' . $tax_name . '][]';
+        $input_id = "tax-input-{$tax_name}";
+
+        // Hierarchical taxonomies expect term ID, non-hierarchical the slug
+        if ( is_taxonomy_hierarchical( $tax_name ) ) {
+                $hierarchical = 1;
+                $value_field = 'term_id';
+        } else {
+                $hierarchical = 0;
+                $value_field = 'slug';
+        }
+
+        $terms = get_the_terms( $post, $tax_name );
+
+        if ( empty( $terms ) ) {
+                $selected = 0;
+        } else {
+                // If there is more than one term assigned, only the first one will be selected
+                // and thus a post save will result in only that term being assigned.
+                // This case could happen if changing a taxonomy's assignment callback
+                // from one that allows multiple select to not.
+                $selected = array_shift( $terms );
+                $selected = $selected->$value_field;
+        }
+?>
+        <div id="taxonomy-<?php echo $tax_name; ?>" class="tax-dropdown">
+                <label for="tax-input-<?php echo $tax_name; ?>"><?php echo $taxonomy->labels->add_or_remove_items; ?></label>
+                <?php
+                $dropdown_args = array(
+                        'taxonomy'          => $tax_name,
+                        'hide_empty'        => 0,
+                        'id'                => $input_id,
+                        'name'              => $input_name,
+                        'orderby'           => 'name',
+                        'hierarchical'      => $hierarchical,
+//// @TODO: Categories can't really have a "none" because of default category
+                        'show_option_none'  => __( '&mdash; Select &mdash;' ),
+                        'option_none_value' => 0,
+                        'value_field'       => $value_field,
+                        'selected'          => $selected,
+                );
+
+                /**
+                 * Filters the arguments for the taxonomy select dropdown on the Post Edit page.
+                 *
+                 * @since 4.7.0
+                 *
+                 * @param array $dropdown_args {
+                 *     Optional. Array of arguments to generate parent dropdown.
+                 *
+                 *     @type string   $tax_name          Name of the taxonomy to retrieve.
+                 *     @type bool     $hide_if_empty     True to skip generating markup if no
+                 *                                       terms are found. Default 0.
+                 *     @type string   $id                Value for the 'id' attribute
+                 *                                       of the select element.
+                 *                                       Default "tax-input-{$tax_name}" where
+                 *                                       `$tax_name` is the taxonomy name.
+                 *     @type string   $name              Value for the 'name' attribute
+                 *                                       of the select element.
+                 *                                       Default "post_category" or
+                 *                                       "tax_input[{$tax_name}] where
+                 *                                       `$tax_name` is the taxonomy name.
+                 *     @type string   $orderby           Which column to use for ordering
+                 *                                       terms. Default 'name'.
+                 *     @type bool|int $hierarchical      Whether to traverse the taxonomy
+                 *                                       hierarchy. Default 1.
+                 *     @type string   $show_option_none  Text to display for the "none" option.
+                 *                                       Default "&mdash; Select &mdash;".
+                 *     @type string   $option_none_value Value for the "none" option. Default 0.
+                 *     @type string   $selected          Value for the selected option.
+                 *                                       Default a term ID or slug.
+                 * }
+                 */
+                $dropdown_args = apply_filters( 'post_edit_taxonomy_dropdown_args', $dropdown_args );
+
+                wp_dropdown_categories( $dropdown_args );
+//// @TODO: Adding new, with a parent for hierarchical, and a filter to disable?
+                ?>
+        </div>
+<?php
+}
+
+/**
  * Display post excerpt form fields.
  *
  * @since 2.6.0