Add single-ID.php to template hirearchy

[isaacchapman]

This might some people to go a bit over the top in regards to customizing how each individual post is displayed, but why not add a single-ID.php (where ID is the Post's ID) to the ​template hierarchy in a similar manner as the category template hierarchy?

The following replacement for the get_single_template() function in /wp-includes/theme.php also includes an apply_filters('single_template') for why not reasons:

function get_single_template() {
	global $post;
	$template = '';
	if ( $post && $post->ID && file_exists(TEMPLATEPATH . "/single-" . $post->ID . '.php') )
		$template = TEMPLATEPATH . "/single-" . $post->ID . '.php';
	else 
		$template = get_query_template('single');

	return apply_filters('single_template', $template);
}

[markjaquith]

why not add a single-ID.php

A better question to ask is "why?" If every "why not?" feature was added, we'd be drowning in code bloat. Is there a specific need for this? It seems highly unlikely that people are going to create custom templates for posts. Are they supposed to know the post ID ahead of time? Or is this for creating specific templates for old posts? Why? Pages are more likely to require a specific template, but we already have the Page Templates feature handling that.