Index: src/wp-includes/functions.php
===================================================================
--- src/wp-includes/functions.php	(revision 29311)
+++ src/wp-includes/functions.php	(working copy)
@@ -21,7 +21,7 @@
  * @param string $format    Format of the date to return.
  * @param string $date      Date string to convert.
  * @param bool   $translate Whether the return date should be translated. Default true.
- * @return string|int Formatted date string, or Unix timestamp.
+ * @return string|int|bool Formatted date string or Unix timestamp. False if $date is empty.
  */
 function mysql2date( $format, $date, $translate = true ) {
 	if ( empty( $date ) )
Index: src/wp-includes/general-template.php
===================================================================
--- src/wp-includes/general-template.php	(revision 29311)
+++ src/wp-includes/general-template.php	(working copy)
@@ -1725,11 +1725,15 @@
  *
  * @param  string      $d    Optional. PHP date format defaults to the date_format option if not specified.
  * @param  int|WP_Post $post Optional. Post ID or WP_Post object. Default current post.
- * @return string Date the current post was written.
+ * @return string|bool Date the current post was written. False on failure.
  */
 function get_the_date( $d = '', $post = null ) {
 	$post = get_post( $post );
 
+	if ( ! $post ) {
+		return false;
+	}
+
 	if ( '' == $d ) {
 		$the_date = mysql2date( get_option( 'date_format' ), $post->post_date );
 	} else {
@@ -1839,11 +1843,15 @@
  *                          was written. Either 'G', 'U', or php date format defaults
  *                          to the value specified in the time_format option. Default empty.
  * @param int|WP_Post $post WP_Post object or ID. Default is global $post object.
- * @return string|int Formatted date string, or Unix timestamp.
+ * @return string|int|bool Formatted date string or Unix timestamp. False on failure.
  */
 function get_the_time( $d = '', $post = null ) {
 	$post = get_post($post);
 
+	if ( ! $post ) {
+		return false;
+	}
+
 	if ( '' == $d )
 		$the_time = get_post_time(get_option('time_format'), false, $post, true);
 	else
@@ -1873,11 +1881,15 @@
  * @param bool        $gmt       Optional. Whether to retrieve the GMT time. Default false.
  * @param int|WP_Post $post      WP_Post object or ID. Default is global $post object.
  * @param bool        $translate Whether to translate the time string. Default false.
- * @return string|int Formatted date string, or Unix timestamp.
+ * @return string|int|bool Formatted date string or Unix timestamp. False on failure.
  */
 function get_post_time( $d = 'U', $gmt = false, $post = null, $translate = false ) {
 	$post = get_post($post);
 
+	if ( ! $post ) {
+		return false;
+	}
+
 	if ( $gmt )
 		$time = $post->post_date_gmt;
 	else
@@ -1951,15 +1963,20 @@
  *
  * @since 2.0.0
  *
- * @param string $d Optional, default is 'U'. Either 'G', 'U', or php date format.
- * @param bool $gmt Optional, default is false. Whether to return the gmt time.
- * @param int|object $post Optional, default is global post object. A post_id or post object
- * @param bool $translate Optional, default is false. Whether to translate the result
- * @return string Returns timestamp
+ * @param string      $d         Optional. Format to use for retrieving the time the post
+ *                               was modified. Either 'G', 'U', or php date format. Default 'U'.
+ * @param bool        $gmt       Optional. Whether to retrieve the GMT time. Default false.
+ * @param int|WP_Post $post      WP_Post object or ID. Default is global $post object.
+ * @param bool        $translate Whether to translate the time string. Default false.
+ * @return string|int|bool Formatted date string or Unix timestamp. False on failure.
  */
 function get_post_modified_time( $d = 'U', $gmt = false, $post = null, $translate = false ) {
 	$post = get_post($post);
 
+	if ( ! $post ) {
+		return false;
+	}
+
 	if ( $gmt )
 		$time = $post->post_modified_gmt;
 	else