Media: URL encode spaces in srcset attributes.

In some cases, images in the media library may contain spaces in
their filenames. This results in an invalid `srcset` attribute,
causing broken images on the front end. This change fixes the issue
by replacing spaces in URLs with URL encoded '%20' characters before
returning the `srcset` string.

Props underdude, joemcgill.
Fixes #36549.
Built from https://develop.svn.wordpress.org/trunk@38052


git-svn-id: http://core.svn.wordpress.org/trunk@37993 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/media.php

@@ -1142,7 +1142,7 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
 	 * @param array  $size_array    Array of width and height values in pixels (in that order).
 	 * @param string $image_src     The 'src' of the image.
 	 * @param array  $image_meta    The image meta data as returned by 'wp_get_attachment_metadata()'.
- 	 * @param int    $attachment_id Image attachment ID or 0.
+	 * @param int    $attachment_id Image attachment ID or 0.
 	 */
 	$sources = apply_filters( 'wp_calculate_image_srcset', $sources, $size_array, $image_src, $image_meta, $attachment_id );
 
@@ -1154,7 +1154,7 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
 	$srcset = '';
 
 	foreach ( $sources as $source ) {
-		$srcset .= $source['url'] . ' ' . $source['value'] . $source['descriptor'] . ', ';
+		$srcset .= str_replace( ' ', '%20', $source['url'] ) . ' ' . $source['value'] . $source['descriptor'] . ', ';
 	}
 
 	return rtrim( $srcset, ', ' );

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.6-beta2-38051';
+$wp_version = '4.6-beta2-38052';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.