Debugging: Difference between revisions

Revision as of 18:18, 10 February 2025

Debugging a PHP application can involve quite a bit of machinery, and effort getting that machinery setup. But it's worth it because what alternative is there? echo? Come on!

Thanks to Derick Rethans, XDebug can do a ton of cool things for you. For example, it overloads var_dump() and gives you control over how you want deeply nested data structures to be displayed.

We did an old deep dive using NetBeans and XDebug on a complex CiviCRM mailer embedded as a module in Drupal

A more current setup would be debugging Semantic MediaWiki in a Docker container using VSCode with PHPDebug.

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 Debugging a PHP application can involve quite a bit of machinery, and effort getting that machinery setup.  But it's worth it because what alternative is there? <code>echo</code>?  Come on!
-Thanks to [http://derickrethans.nl/who.html Derick Rethans], xdebug can do a ton of cool things for you.  For example, it overloads <code>[https://secure.php.net/var_dump var_dump()]</code> and gives '''you''' [http://www.xdebug.org/docs/display control over how you want deeply nested data structures to be displayed].
+Thanks to [http://derickrethans.nl/who.html Derick Rethans], XDebug can do a ton of cool things for you.  For example, it overloads <code>[https://secure.php.net/var_dump var_dump()]</code> and gives '''you''' [http://www.xdebug.org/docs/display control over how you want deeply nested data structures to be displayed].
-Once you have NetBeans and XDebug operating, you can [[CiviCRM/debugging|debug complex applications like CiviCRM]]
+We did an old deep dive using NetBeans and XDebug [[CiviCRM/debugging|on a complex CiviCRM mailer embedded as a module in Drupal]]
-== First get Xdebug setup ==
+A more current setup would be [[debugging Semantic MediaWiki in a Docker container using VSCode with PHPDebug]].
-Xdebug is the project for debugging PHP.  The [http://xdebug.org/wizard.php wizard] will show you how to upgrade your package version.  In my case, the Xdebug packaged for Ubuntu was 2.2.3, but the more recent version is '''2.3.3'''
-=== Summary ===
-Here is what the wizard reported for me AFTER my recent installation of xdebug
-<blockquote>
-'''Xdebug installed:''' 2.3.3 <br />
-'''Server API:''' Apache 2.0 Handler <br />
-'''Windows:''' no <br />
-'''Zend Server:''' no <br />
-'''PHP Version:''' 5.5.9-1 <br />
-'''Zend API nr:''' 220121212 <br />
-'''PHP API nr:''' 20121212 <br />
-'''Debug Build:''' no <br />
-'''Thread Safe Build:''' no <br />
-'''Configuration File Path:''' /etc/php5/apache2 <br />
-'''Configuration File:''' /etc/php5/apache2/php.ini <br />
-'''Extensions directory:''' /usr/lib/php5/20121212+lfs
-</blockquote>
-Caveat: the wizard can't really tell where the xdebug configuration lives (in the case of many subsidiary ini files).  In Ubuntu, there might be a file in <code>/etc/php5/conf.d</code> In my case I actually did have <code>/etc/php5/conf.d/xdebug.ini</code>, but that file is superfluous because there are symbolic links for both '''apache2''' and '''cli''' that go to
-<code>/etc/php5/mods-available/xdebug.ini</code> (which helps PHP configuration to be the same for both runtimes.)  Bottom line: run <code>locate xdebug.ini</code> to find out whether you have a duplicate/conflicting file; merge those files down to one; and make any overrides that you need from the default settings which xdebug will use if left unconfigured.  Then <code>sudo service apache2 restart</code> and check the output of <code>phpinfo()</code> for correctness.
-The defaults are probably all good, but you may want to specify some of the following:
-<source lang="ini">
-; the old one installed by apt-get
-; zend_extension=/usr/lib/php5/20090626+lfs/xdebug.so
-; as of php 5.5 you no longer need to supply a full path to the zend_extension= token
-; but it doesn't hurt, and may be required if you have multiple .so files lying around
-zend_extension=/usr/lib/php5/20121212+lfs/xdebug.so
-; enable debugging
-xdebug.remote_enable = On
-; working from local machine
-; xdebug.remote_host = "127.0.0.1"
-; debugging from any machine on the local network, as well as through the router
-xdebug.remote_host = "192.168.1.0/24,127.0.0.1"
-; set which debug client protocol we want
-xdebug.remote_handler = "dbgp"
-; enable anyone with access to the machine to start a debugging session
-; this setting also helps when you're having difficulty with the connection setup
-; xdebug.remote_connect_back 1
-</source>
-Once you see xdebug in your <code>phpinfo()</code> output, you know it's enabled -- which means that you can already get xdebug functionality out of your PHP scripts (e.g. var_dump() is overridden).  But how do you get debugging working so that you can use it with your IDE?  That is covered in the '[http://www.xdebug.org/docs/remote remote]' section of the manual.
-{{Highlight |
-text= If you want to use [https://secure.php.net/manual/en/opcache.installation.php OPcache] with Xdebug, you must load OPcache before Xdebug.  In general, extensions are loaded in the order found in php.ini. See https://wiki.php.net/internals/extensions and [https://wiki.php.net/_detail/internals/extensions_lifetime.png?id=internals%3Aextensions this graphic] for more info}}
-Following the sage advice of the [http://wiki.netbeans.org/HowToConfigureXDebug#General_Information Netbeans wiki], you want to get xdebug's '''debugclient''' working on localhost first, then add Netbeans.
-xdebug provides several configuration parameters as well as functions that you can use in your debugging code.  One important parameter is the <code>[http://www.xdebug.org/docs/stack_trace xdebug.file_link_format]</code> which determines the format of the links that are shown in stack traces.  This allows for integration with your IDE so that, for example, Netbeans will find and open the file in your local sources.
-[http://www.xdebug.org/docs/profiler Profiling] your PHP code is another feature enabled by xdebug.
-== Resources ==
-* http://www.devside.net/wamp-server/netbeans-waiting-for-connection-netbeans-xdebug-issue