From c9c9af5df891e3face6176e41fd1a241fb2aecdc Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Thu, 5 Feb 2015 19:03:52 +0000
Subject: [PATCH] Introduce `'value_field'` parameter to `wp_dropdown_pages()`.

This parameter allows developers to choose the post field that will be used to
fill in the 'option' attribute of the generated dropdown markup.

See [31006] #30306 for a parallel enhancement in `wp_dropdown_categories()`.

Props jfarthing84.
Fixes #12494.

git-svn-id: https://develop.svn.wordpress.org/trunk@31338 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/post-template.php     | 16 +++++--
 tests/phpunit/tests/post/template.php | 68 ++++++++++++++++++++++++++-
 2 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/src/wp-includes/post-template.php b/src/wp-includes/post-template.php
index 927c6592cd..e91358ec6a 100644
--- a/src/wp-includes/post-template.php
+++ b/src/wp-includes/post-template.php
@@ -971,7 +971,8 @@ function wp_dropdown_pages( $args = '' ) {
 		'selected' => 0, 'echo' => 1,
 		'name' => 'page_id', 'id' => '',
 		'show_option_none' => '', 'show_option_no_change' => '',
-		'option_none_value' => ''
+		'option_none_value' => '',
+		'value_field' => 'ID',
 	);
 
 	$r = wp_parse_args( $args, $defaults );
@@ -1425,15 +1426,20 @@ class Walker_PageDropdown extends Walker {
 	 * @since 2.1.0
 	 *
 	 * @param string $output Passed by reference. Used to append additional content.
-	 * @param object $page Page data object.
-	 * @param int $depth Depth of page in reference to parent pages. Used for padding.
-	 * @param array $args Uses 'selected' argument for selected page to set selected HTML attribute for option element.
+	 * @param object $page   Page data object.
+	 * @param int    $depth  Depth of page in reference to parent pages. Used for padding.
+	 * @param array  $args   Uses 'selected' argument for selected page to set selected HTML attribute for option
+	 *              element. Uses 'value_field' argument to fill "value" attribute. See {@see wp_dropdown_pages()}.
 	 * @param int $id
 	 */
 	public function start_el( &$output, $page, $depth = 0, $args = array(), $id = 0 ) {
 		$pad = str_repeat('&nbsp;', $depth * 3);
 
-		$output .= "\t<option class=\"level-$depth\" value=\"$page->ID\"";
+		if ( ! isset( $args['value_field'] ) || ! isset( $page->{$args['value_field']} ) ) {
+			$args['value_field'] = 'ID';
+		}
+
+		$output .= "\t<option class=\"level-$depth\" value=\"" . esc_attr( $page->{$args['value_field']} ) . "\"";
 		if ( $page->ID == $args['selected'] )
 			$output .= ' selected="selected"';
 		$output .= '>';
diff --git a/tests/phpunit/tests/post/template.php b/tests/phpunit/tests/post/template.php
index 886117e2ce..9a34180a2a 100644
--- a/tests/phpunit/tests/post/template.php
+++ b/tests/phpunit/tests/post/template.php
@@ -131,4 +131,70 @@ NO;
 		) );
 		$this->assertEquals( $option_no_change, $output );
 	}
-}
\ No newline at end of file
+
+	/**
+	 * @ticket 12494
+	 */
+	public function test_wp_dropdown_pages_value_field_should_default_to_ID() {
+		$p = $this->factory->post->create( array(
+			'post_type' => 'page',
+		) );
+
+		$found = wp_dropdown_pages( array(
+			'echo' => 0,
+		) );
+
+		// Should contain page ID by default.
+		$this->assertContains( 'value="' . $p . '"', $found );
+	}
+
+	/**
+	 * @ticket 12494
+	 */
+	public function test_wp_dropdown_pages_value_field_ID() {
+		$p = $this->factory->post->create( array(
+			'post_type' => 'page',
+		) );
+
+		$found = wp_dropdown_pages( array(
+			'echo' => 0,
+			'value_field' => 'ID',
+		) );
+
+		$this->assertContains( 'value="' . $p . '"', $found );
+	}
+
+	/**
+	 * @ticket 12494
+	 */
+	public function test_wp_dropdown_pages_value_field_post_name() {
+		$p = $this->factory->post->create( array(
+			'post_type' => 'page',
+			'post_name' => 'foo',
+		) );
+
+		$found = wp_dropdown_pages( array(
+			'echo' => 0,
+			'value_field' => 'post_name',
+		) );
+
+		$this->assertContains( 'value="foo"', $found );
+	}
+
+	/**
+	 * @ticket 12494
+	 */
+	public function test_wp_dropdown_pages_value_field_should_fall_back_on_ID_when_an_invalid_value_is_provided() {
+		$p = $this->factory->post->create( array(
+			'post_type' => 'page',
+			'post_name' => 'foo',
+		) );
+
+		$found = wp_dropdown_pages( array(
+			'echo' => 0,
+			'value_field' => 'foo',
+		) );
+
+		$this->assertContains( 'value="' . $p . '"', $found );
+	}
+}