next_post_link() function give same URL of post in wordpress - wordpress

Question

When I am writing below code for recent posts and then after I write code for next and previous link then that function will give me same link of post. If I am comment out "$tags = wp_get_post_tags($post->ID);" This line then It'll print next post link. How can I resolved this error ? please help me.
<?php
//for use in the loop, list 5 post titles related to first tag on current post
$tags = wp_get_post_tags($post->ID);
if ($tags) {
echo '<div class="articlecontent font16 bold fontgray">Related Posts</div>';
$first_tag = $tags[0]->term_id;
$args=array(
'tag__in' => array($first_tag),
'post__not_in' => array($post->ID),
'showposts'=>5,
'caller_get_posts'=>1
);
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {
echo '<div class="articlecontent"><ul>';
while ($my_query->have_posts()) : $my_query->the_post(); ?>
<li><?php the_title(); ?></li>
<?php
endwhile;
echo "</ul></div>";
}
}
?>
<div class="nextprevbar">
<div class="prevtopic"><?php
previous_post_link( '%link', '<img border="0" alt="" src="'.get_template_directory_uri().'/images/prev-bullet.gif">' . _x( ' ', 'Previous post link', 'twentyten' ) . ' %title' ); ?></div>
<div class="nexttopic"><?php next_post_link( '%link', '%title <img border="0" alt="" src="'.get_template_directory_uri().'/images/next-bullet.gif">' . _x( ' ', 'Next post link', 'twentyten' ) . '</span>' ); ?></div>
</div>

Answer 1

The problem has to be in the $post variable. Before this line is executed:
while ($my_query->have_posts()) : $my_query->the_post(); ?>
the $post var holds the current post data (I guess this code is inside single.php?). But after this line, and inside the loop, the $post var holds your various recent posts, one by one (you setup the $post variable when you call the_post() ).
After that loop (bellow the endwhile), $post will hold the data of the last post retrieved in that loop.
previous_post_link() and next_post_link() need to access $post for reference of the current post, but they are taking as reference the last post of your recent posts, instead of the post being read by your user.
I don't know what the html structure of this page is, but I would put the recent posts list AFTER the navigation links (next, previous posts). That would solve the problem if I am right, and in my opinion it would be semantically clearer.
Or you could also try this:
Add this line:
$currentPost = clone $post;
Before:
$my_query = new WP_Query($args);
And add this line:
<?php $post = $currentPost; ?>
Before you call next and previous post links functions.