gistfile1.diff

diff --git wp-includes/media.php wp-includes/media.php
index e3b9008..5958d37 100644
--- wp-includes/media.php
+++ wp-includes/media.php
@@ -726,7 +726,7 @@ add_shortcode('caption', 'img_caption_shortcode');
 function img_caption_shortcode($attr, $content = null) {
 
 	// Allow plugins/themes to override the default caption template.
-	$output = apply_filters('img_caption_shortcode', '', $attr, $content);
+	$output = apply_filters( 'img_caption_shortcode', '', $attr, do_shortcode( $content) );
 	if ( $output != '' )
 		return $output;
 
@@ -734,16 +734,49 @@ function img_caption_shortcode($attr, $content = null) {
 		'id'	=> '',
 		'align'	=> 'alignnone',
 		'width'	=> '',
-		'caption' => ''
+		'caption' => false
 	), $attr));
 
-	if ( 1 > (int) $width || empty($caption) )
+	if ( 1 > (int) $width || ( $caption !== false && empty( $caption ) ) )
 		return $content;
 
-	if ( $id ) $id = 'id="' . esc_attr($id) . '" ';
+	return sprintf(
+		'<div %s class="wp-caption %s" style="width: %dpx">%s</div>',
+		$id ? 'id="' . esc_attr( $id ) . '"' : '',
+		esc_attr( $align ),
+		(10 + (int) $width ),
+		// Leave this for backcompat with <3.4.0 shortcode version
+		$caption ? do_shortcode( $content ) . img_caption_text_shortcode( array(), $caption ) : do_shortcode( $content ) 
+	);
+}
+
+add_shortcode( 'caption_text', 'img_caption_text_shortcode' );
+
+/**
+ * The Caption Text shortcode.
+ *
+ * Allows a plugin to replace the content that would otherwise be returned. The
+ * filter is 'img_caption_text_shortcode' and passes an empty string, the attr
+ * parameter and the content parameter values.
+ *
+ * The supported attributes for the shortcode are 'class'.
+ *
+ * @since 3.4.0
+ *
+ * @param array $attr Attributes attributed to the shortcode text.
+ * @param string $content Optional. Shortcode text.
+ * @return string
+ */
+function img_caption_text_shortcode( $attr, $content) {
+
+	// Allow plugins/themes to override the default caption text template.
+	$output = apply_filters( 'img_caption_text_shortcode', '', $attr, $content );
+	if ( $output != '' )
+		return $output;
+
+	extract( shortcode_atts( array( 'class'	=> 'wp-caption-text' ), $attr ) );
 
-	return '<div ' . $id . 'class="wp-caption ' . esc_attr($align) . '" style="width: ' . (10 + (int) $width) . 'px">'
-	. do_shortcode( $content ) . '<p class="wp-caption-text">' . $caption . '</p></div>';
+	return '<p class="' . $class . '">' . $content . '</p>';
 }
 
 add_shortcode('gallery', 'gallery_shortcode');