my list of debugging functions to keep in an MU file

norcross-debug-functions.php

<?php
/*
Plugin Name: Norcross Debug Functions
Plugin URI: https://gist.github.com/norcross/7864205/
Description: A set of functions I use on all sites while building
Author: Andrew Norcross
Version: 0.0.1
Requires at least: 3.0
Author URI: http://andrewnorcross.com
*/

function rkv_bypass_auto_update_email( $send, $type, $core_update, $result ) {

	// check our type and bail if successful
	if ( ! empty( $type ) && $type == 'success' ) {
		return false;
	}
	// return the send function
	return true;

}

add_filter( 'auto_core_update_send_email', 'rkv_bypass_auto_update_email', 10, 4 );


/**
 * display array results in a readable fashion
 *
 * @param  [type]  $s      [description]
 * @param  boolean $die    [description]
 * @param  boolean $return [description]
 * @return [type]          [description]
 */
function preprint( $s, $die = false, $return = false ) {

	// set an empty
	$code   = '';

	// some CSS to make it a bit more readable
	$style  = 'background-color: #fff; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;';

	// the code itself
	$code  .= '<pre style="' . $style . '">';
	$code  .= print_r( $s, 1 );
	$code  .= '</pre>';

	// return if requested
	if ( $return ) {
		return $code;
	}

	// print if requested ( the default )
	if ( ! $return ) {
		print $code;
	}

	// die if you want to die
	if ( $die ) {
		die();
	}
}

/*
 *
 * Debugging Convenience function
 *
 * Shows all the "filters" currently attached to a hook
 *
 * ex. 
 * print_filters_for('the_content');
 *
 */
function print_filters_for( $hook = '' ) {
    global $wp_filter;
    if( empty( $hook ) || !isset( $wp_filter[$hook] ) )
        return;
    print '<pre>';
    print_r( $wp_filter[$hook] );
    print '</pre>';
}

/**
 * [fullquery description]
 * @return [type] [description]
 */
function fullquery() {
	global $wp_query;

	preprint( $wp_query, true );
}

/**
 * Suppress errors generated by specified WordPress plugins.
 *
 * Include in the auto_prepend_file php.ini directive to ignore globally. Update
 * the directory separator as required.
 *
 * @see http://plugins.trac.wordpress.org/browser/ostrichcize/tags/0.1/ostrichcize.php#L146
 *
 * @param string $errno The error number.
 * @param string $errstr The error message.
 * @param string $errfile Path to the file that caused the error.
 * @param int $errline Line number of the error.
 * @return bool True to success error reporting; false to use default error handler.
 */

function blazersix_wpdev_error_handler( $errno, $errstr, $errfile, $errline ) {
	$paths = array(
		'plugins\\wordpress-importer\\'
	);

	foreach ( $paths as $path ) {
		if ( false !== strpos( $errstr, $path ) ) {
			return true;
		}

		if ( false !== strpos( $errfile, $path ) ) {
			return true;
		}
	}

	// The path was not found, so report the error.
	return false;
}
set_error_handler( 'blazersix_wpdev_error_handler' );

/*
 *
 * parse a JSON item
 *
 * json_parse($variable);
 *
 */
 
function json_parse($text){
	$parsedText = str_replace('\n', '', $text);
	return str_replace('\t', '', $parsedText);
}

/**
 * set up some quick links for the admin bar
 *
 * @param  WP_Admin_Bar $wp_admin_bar [description]
 * @return [type]                     [description]
 */
function rkv_admin_bar_static( WP_Admin_Bar $wp_admin_bar ) {
	// bail if current user doesnt have cap
	if ( ! current_user_can( 'manage_options' ) ) {
		return;
	}
	// remove customizer
	$wp_admin_bar->remove_node( 'customize' );
	// add a parent item
	$wp_admin_bar->add_node(
		array(
			'id'    => 'rkv-dev-links',
			'title' => 'RKV Dev Links',
		)
	);
	// add GitHub issues
	$wp_admin_bar->add_node(
		array(
			'id'        => 'github-issues',
			'title'     => 'GitHub Issues',
			'href'      => 'https://github.com/project-name/issues',
			'position'  => 0,
			'parent'    => 'rkv-dev-links',
			'meta'      => array(
				'title' => 'GitHub Issues',
				'target' => '_blank'
			)
		)
	);
	// add CMB2 wiki
	$wp_admin_bar->add_node(
		array(
			'id'        => 'cmb2-wiki-site',
			'title'     => 'CMB2 Wiki',
			'href'      => 'https://github.com/WebDevStudios/CMB2/wiki/',
			'parent'    => 'rkv-dev-links',
			'position'  => 0,
			'meta'      => array(
				'title' => 'CMB2 Wiki',
				'target' => '_blank'
			)
		)
	);
	// add live staging site
	$wp_admin_bar->add_node(
		array(
			'id'        => 'staging-site',
			'title'     => 'Staging Site',
			'href'      => 'http://devsite-url.com/',
			'parent'    => 'rkv-dev-links',
			'position'  => 0,
			'meta'      => array(
				'title' => 'Staging Site',
				'target' => '_blank'
			)
		)
	);
}
add_action( 'admin_bar_menu', 'rkv_admin_bar_static', 9999 );

/**
 * [rkv_auto_login description]
 * @return [type] [description]
 */
function rkv_auto_login() {

	// bail on ajax
	if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) {
		return;
	}

	// allow for test log out
	if ( isset( $_GET['testlogout'] ) ) {

		// handle the logout
		wp_logout();

		// clear the auth cookies
		wp_clear_auth_cookie();

		// and return
		return;
	}

	// bail if the user is logged in
	if ( is_user_logged_in() ) {
		return;
	}

	// get the user
	$user   = get_userdata( 1 ); // 1 being the ID that I want

	// bail if I don't have userdata
	if ( empty( $user ) || ! is_object( $user ) ) {
		return;
	}

	// set the current user
	wp_set_current_user( $user->ID, $user->user_login );

	// set the auth cookie
	wp_set_auth_cookie( $user->ID );

	// now actually log in
	do_action( 'wp_login', $user->user_login );
}

add_action( 'init', 'rkv_auto_login' );
add_action( 'admin_init', 'rkv_auto_login' );