General: Backport several commits for release.

- Embeds: Ensure that the title attribute is set correctly on embeds.
- Editor: Prevent HTML decoding on by setting the proper editor context.
- Formatting: Ensure that `wp_validate_redirect()` sanitizes a wider variety of characters.
- Themes: Ensure a broken theme name is returned properly.
- Administration: Add a new filter to extend set-screen-option. 

Merges [47947-47951] to the 5.0 branch.
Props xknown, sstoqnov, vortfu, SergeyBiryukov, whyisjake.


git-svn-id: https://develop.svn.wordpress.org/branches/5.0@47964 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/media.php

@@ -2831,8 +2831,11 @@ function edit_form_image_editor( $post ) {
 	<label for="attachment_content"><strong><?php _e( 'Description' ); ?></strong><?php
 	if ( preg_match( '#^(audio|video)/#', $post->post_mime_type ) ) {
 		echo ': ' . __( 'Displayed on attachment pages.' );
-	} ?></label>
-	<?php wp_editor( $post->post_content, 'attachment_content', $editor_args ); ?>
+	}
+
+	?>
+	</label>
+	<?php wp_editor( format_to_edit( $post->post_content ), 'attachment_content', $editor_args ); ?>
 
 	</div>
 	<?php

src/wp-admin/includes/misc.php

@@ -620,24 +620,46 @@ function set_screen_options() {
 					return;
 				break;
 			default:
+				if ( '_page' === substr( $option, -5 ) || 'layout_columns' === $option ) {
+					/**
+					 * Filters a screen option value before it is set.
+					 *
+					 * The filter can also be used to modify non-standard [items]_per_page
+					 * settings. See the parent function for a full list of standard options.
+					 *
+					 * Returning false to the filter will skip saving the current option.
+					 *
+					 * @since 2.8.0
+					 * @since 5.4.2 Only applied to options ending with '_page',
+					 *              or the 'layout_columns' option.
+					 *
+					 * @see set_screen_options()
+					 *
+					 * @param bool   $keep   Whether to save or skip saving the screen option value.
+					 *                       Default false.
+					 * @param string $option The option name.
+					 * @param int    $value  The number of rows to use.
+					 */
+					$value = apply_filters( 'set-screen-option', false, $option, $value ); // phpcs:ignore WordPress.NamingConventions.ValidHookName.UseUnderscores
+				}
 
 				/**
 				 * Filters a screen option value before it is set.
 				 *
-				 * The filter can also be used to modify non-standard [items]_per_page
-				 * settings. See the parent function for a full list of standard options.
+				 * The dynamic portion of the hook, `$option`, refers to the option name.
 				 *
 				 * Returning false to the filter will skip saving the current option.
 				 *
-				 * @since 2.8.0
+				 * @since 5.4.2
 				 *
 				 * @see set_screen_options()
 				 *
-				 * @param bool|int $value  Screen option value. Default false to skip.
-				 * @param string   $option The option name.
-				 * @param int      $value  The number of rows to use.
+				 * @param bool   $keep   Whether to save or skip saving the screen option value.
+				 *                       Default false.
+				 * @param string $option The option name.
+				 * @param int    $value  The number of rows to use.
 				 */
-				$value = apply_filters( 'set-screen-option', false, $option, $value );
+				$value = apply_filters( "set_screen_option_{$option}", false, $option, $value );
 
 				if ( false === $value )
 					return;

src/wp-admin/themes.php

@@ -337,7 +337,7 @@
 	</tr>
 	<?php foreach ( $broken_themes as $broken_theme ) : ?>
 		<tr>
-			<td><?php echo $broken_theme->get( 'Name' ) ? $broken_theme->display( 'Name' ) : $broken_theme->get_stylesheet(); ?></td>
+			<td><?php echo $broken_theme->get( 'Name' ) ? $broken_theme->display( 'Name' ) : esc_html( $broken_theme->get_stylesheet() ); ?></td>
 			<td><?php echo $broken_theme->errors()->get_error_message(); ?></td>
 			<?php
 			if ( $can_delete ) {

src/wp-includes/pluggable.php

@@ -1327,7 +1327,7 @@ function wp_safe_redirect($location, $status = 302) {
  * @return string redirect-sanitized URL
  **/
 function wp_validate_redirect($location, $default = '') {
-	$location = trim( $location, " \t\n\r\0\x08\x0B" );
+	$location = wp_sanitize_redirect( trim( $location, " \t\n\r\0\x08\x0B" ) );
 	// browsers will assume 'http' is your protocol, and will obey a redirect to a URL starting with '//'
 	if ( substr($location, 0, 2) == '//' )
 		$location = 'http:' . $location;