Include trashed posts in url_to_postid

micropubfilter.php

<?php

function micropub_url_to_postid($url) {
	global $wp_rewrite;

	/**
	 * Filter the URL to derive the post ID from.
	 *
	 * @since 2.2.0
	 *
	 * @param string $url The URL to derive the post ID from.
	 */
	// $url = apply_filters( 'url_to_postid', $url ); // this is the filter!

	// First, check to see if there is a 'p=N' or 'page_id=N' to match against
	if ( preg_match('#[?&](p|page_id|attachment_id)=(\d+)#', $url, $values) )	{
		$id = absint($values[2]);
		if ( $id )
			return home_url( '/?p=' . $id );
	}

	// Check to see if we are using rewrite rules
	$rewrite = $wp_rewrite->wp_rewrite_rules();

	// Not using rewrite rules, and 'p=N' and 'page_id=N' methods failed, so we're out of options
	if ( empty($rewrite) )
		return home_url( '/?p=0' );

	// Get rid of the #anchor
	$url_split = explode('#', $url);
	$url = $url_split[0];

	// Get rid of URL ?query=string
	$url_split = explode('?', $url);
	$url = $url_split[0];

	// Add 'www.' if it is absent and should be there
	if ( false !== strpos(home_url(), '://www.') && false === strpos($url, '://www.') )
		$url = str_replace('://', '://www.', $url);

	// Strip 'www.' if it is present and shouldn't be
	if ( false === strpos(home_url(), '://www.') )
		$url = str_replace('://www.', '://', $url);

	// Strip 'index.php/' if we're not using path info permalinks
	if ( !$wp_rewrite->using_index_permalinks() )
		$url = str_replace( $wp_rewrite->index . '/', '', $url );

	if ( false !== strpos( trailingslashit( $url ), home_url( '/' ) ) ) {
		// Chop off http://domain.com/[path]
		$url = str_replace(home_url(), '', $url);
	} else {
		// Chop off /path/to/blog
		$home_path = parse_url( home_url( '/' ) );
		$home_path = isset( $home_path['path'] ) ? $home_path['path'] : '' ;
		$url = preg_replace( sprintf( '#^%s#', preg_quote( $home_path ) ), '', trailingslashit( $url ) );
	}

	// Trim leading and lagging slashes
	$url = trim($url, '/');

	$request = $url;
	$post_type_query_vars = array();

	foreach ( get_post_types( array() , 'objects' ) as $post_type => $t ) {
		if ( ! empty( $t->query_var ) )
			$post_type_query_vars[ $t->query_var ] = $post_type;
	}

	// Look for matches.
	$request_match = $request;
	foreach ( (array)$rewrite as $match => $query) {

		// If the requesting file is the anchor of the match, prepend it
		// to the path info.
		if ( !empty($url) && ($url != $request) && (strpos($match, $url) === 0) )
			$request_match = $url . '/' . $request;

		if ( preg_match("#^$match#", $request_match, $matches) ) {

			if ( $wp_rewrite->use_verbose_page_rules && preg_match( '/pagename=\$matches\[([0-9]+)\]/', $query, $varmatch ) ) {
				// This is a verbose page match, let's check to be sure about it.
				if ( ! get_page_by_path( $matches[ $varmatch[1] ] ) )
					continue;
			}

			// Got a match.
			// Trim the query of everything up to the '?'.
			$query = preg_replace("!^.+\?!", '', $query);

			// Substitute the substring matches into the query.
			$query = addslashes(WP_MatchesMapRegex::apply($query, $matches));

			// Filter out non-public query vars
			global $wp;
			parse_str( $query, $query_vars );
			$query = array();
			foreach ( (array) $query_vars as $key => $value ) {
				if ( in_array( $key, $wp->public_query_vars ) ){
					$query[$key] = $value;
					if ( isset( $post_type_query_vars[$key] ) ) {
						$query['post_type'] = $post_type_query_vars[$key];
						$query['name'] = $value;
						$query['post_status'] = array( 'publish', 'trash' );
					}
				}
			}

			// Do the query
			$query = new WP_Query( $query );
			if ( ! empty( $query->posts ) && $query->is_singular )
				return home_url( '/?p=' . $query->post->ID );
			else
				return home_url( '/?p=0' );
		}
	}
	return home_url( '/?p=0' );
}




add_filter( 'url_to_postid', 'micropub_url_to_postid' );

L104 overrides the default post status settings in WP_Query to include trashed posts.

This is hyper-trashy and untested. Thrown together while I finish lunch.

whoa, that is intense. thanks!