Debugging: Difference between revisions

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For now, this subject will focus on PHP.

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].

== XDebug ==

XDebug is a tool you can't live without once you've learned how to use it.

It offers:

* Step Debugging

* Improvements to PHP's error reporting

* Tracing

* Profiling

* Code Coverage Analysis

XDebug 3.2.0 was [https://xdebug.org/announcements/2022-12-08 released in Dec. 2022] and adds support for '''PHP 8.2''' and drops support for PHP 7.2-7.4

More [https://xdebug.org/announcements recent releases of XDebug] are 3.3.2 and all the way up to '''3.4.1''' as of Jan 2025

=== Installing XDebug ===

Installing XDebug is fairly complicated and only gets more challenging if you are trying to debug sources inside a container or on a remote server. And since the PHP cli is different from the web interpreter, there are differences depending on how you are invoking PHP

https://xdebug.org/docs/install

== Install ==

Ensure that XDebug PHP extension is installed for your PHP environment. It is typically installed via [[PEAR|PECL]], but can be installed with [[Package management|package managers]].

in the console, you can just type <code>php -v</code> which will tell you not just the version of PHP, but also whether XDebug is enabled. More specifically, you could <code>php -r 'echo phpversion("xdebug");'</code>

You should '''also''' check the settings of your installation by looking at the <code>ini</code> file for XDebug<br>

<code>php --ini</code> shows you the ini files that are loaded for your PHP. Inspect the one related to XDebug and ensure that it is set for Debugging.

<code>cat /etc/php/8.3/cli/conf.d/99-xdebug.ini</code>

zend_extension=xdebug

xdebug.mode=coverage,develop,debug,profile,trace

</syntaxhighlight>

Beware that although the '''mode''' is critical and can only be set in the ini file, that setting can be overridden by the environment variable '''XDEBUG_MODE''' - so look for that in container-driven setups.

=== Configuration Report ===

Create a file like '''info.php''' on your development host, and then browse it for a full report of your Debugging environment.

# choose a target

myFile='../../info.php';

# add the phpinfo() function

echo -e "<?php \nphpinfo();\n" > $myFile;

# add the xdeub_info() function

echo -e "\n\nxdebug_info();\n" >> $myFile;

</syntaxhighlight>

== XDebug with VSCode ==

VSCode only supports debugging JavaScript out of the box (including Node.js and TypeScript). For PHP and other languages from Go to Python, you will need to install a debugger extension in VSCode. XDebug is the debugger for PHP, and you will need the [https://marketplace.visualstudio.com/items?itemName=xdebug.php-debug '''PHP Debug''' extension] to VSCode. ''READ the documentation on that page thoroughly''. The extension integrates your IDE with the PHP environment and the XDebug debugger itself.

== Step Debugging ==

Covered at https://xdebug.org/docs/step_debug

== Deeper Dive ==

We did an old deep dive using NetBeans and XDebug [[CiviCRM/debugging|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~~]].

A more current setup would be [[Debug Semantic MediaWiki in Docker using VSCode and XDebug]].

[[Category:Debugging]]

[[Category:Development]]

@@ Line 1: / Line 1: @@
+For now, this subject will focus on PHP.
 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].
+== XDebug ==
+XDebug is a tool you can't live without once you've learned how to use it.
+It offers:
+*   Step Debugging
+*   Improvements to PHP's error reporting
+*   Tracing
+*   Profiling
+*   Code Coverage Analysis
+XDebug 3.2.0 was [https://xdebug.org/announcements/2022-12-08 released in Dec. 2022] and adds support for '''PHP 8.2''' and drops support for PHP 7.2-7.4
+More [https://xdebug.org/announcements recent releases of XDebug] are 3.3.2 and all the way up to '''3.4.1''' as of Jan 2025
+=== Installing XDebug ===
+Installing XDebug is fairly complicated and only gets more challenging if you are trying to debug sources inside a container or on a remote server. And since the PHP cli is different from the web interpreter, there are differences depending on how you are invoking PHP
+https://xdebug.org/docs/install
+== Install ==
+Ensure that XDebug PHP extension is installed for your PHP environment. It is typically installed via [[PEAR|PECL]], but can be installed with [[Package management|package managers]].
+in the console, you can just type <code>php -v</code> which will tell you not just the version of PHP, but also whether XDebug is enabled. More specifically, you could <code>php -r 'echo phpversion("xdebug");'</code>
+You should '''also''' check the settings of your installation by looking at the <code>ini</code> file for XDebug<br>
+<code>php --ini</code> shows you the ini files that are loaded for your PHP. Inspect the one related to XDebug and ensure that it is set for Debugging.
+<code>cat /etc/php/8.3/cli/conf.d/99-xdebug.ini</code>
+<syntaxhighlight lang="bash">
+zend_extension=xdebug
+xdebug.mode=coverage,develop,debug,profile,trace
+</syntaxhighlight>
+Beware that although the '''mode''' is critical and can only be set in the ini file, that setting can be overridden by the environment variable '''XDEBUG_MODE''' - so look for that in container-driven setups.
+=== Configuration Report ===
+Create a file like '''info.php''' on your development host, and then browse it for a full report of your Debugging environment.
+<syntaxhighlight lang="bash">
+# choose a target
+myFile='../../info.php';
+# add the phpinfo() function
+echo -e "<?php \nphpinfo();\n" > $myFile;
+# add the xdeub_info() function
+echo -e "\n\nxdebug_info();\n" >> $myFile;
+</syntaxhighlight>
+== XDebug with VSCode ==
+VSCode only supports debugging JavaScript out of the box (including Node.js and TypeScript). For PHP and other languages from Go to Python, you will need to install a debugger extension in VSCode. XDebug is the debugger for PHP, and you will need the [https://marketplace.visualstudio.com/items?itemName=xdebug.php-debug '''PHP Debug''' extension] to VSCode. ''READ the documentation on that page thoroughly''. The extension integrates your IDE with the PHP environment and the XDebug debugger itself.
+== Step Debugging ==
+Covered at https://xdebug.org/docs/step_debug
+== Deeper Dive ==
 We did an old deep dive using NetBeans and XDebug [[CiviCRM/debugging|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]].
+A more current setup would be [[Debug Semantic MediaWiki in Docker using VSCode and XDebug]].
+[[Category:Debugging]]
+[[Category:Development]]