Xdebug Update: August 2020

Written by Derick Rethans / Original link on Sep. 8, 2020

Xdebug Update: August 2020

London, UK
Tuesday, September 8th 2020, 09:44 BST

Another monthly update where I explain what happened with Xdebug development in this past month. These will be published on the first Tuesday after the 5th of each month. Patreon and GitHub supporters will get it earlier, on the first of each month. You can become a patron to support my work on Xdebug. If you are leading a team or company, then it is also possible to support Xdebug through a subscription.

In August, I worked on Xdebug for about 80 hours, with funding being around 70 hours. I worked mostly on the following things:

Xdebug 3

This month I focussed on making it easier to spot what Xdebug is doing, and how and why it is trying to connect to a debugging client, creating files, etc. For this I reworked Xdebug's logging mechanism. Instead of it just being used for the step debugger, the logging mechanism is now used for everything, and as part of that I've renamed xdebug.remote_log to xdebug.log. The log will contain all messages with levels that match the xdebug.log_level setting, but Xdebug will now also send errors through PHP's standard error mechanism. Errors include not being able to open a log file, to create a profile or trace file, or issues with making debugging connections.

The biggest new addition is the xdebug_info() function , which acts as a Xdebug specific phpinfo() and contains configuration information about Xdebug, but more importantly lists warnings and errors. Where possible, a link to the documentation is included as well, where I set up a new page that includes all the warning and error messages that Xdebug can generate. I have tried to add information about how a specific message is created, and what you can do to resolve the issue if possible.

Modes and Docker

Xdebug 3 introduces modes that can be configured with the xdebug.mode setting. This setting can only be changed in php.ini, and not in an .htaccess file or equivalent, nor in the script with ini_set. Because Docker and containers are a more common development set-up now, a method was needed to be able to change Xdebug's mode without have to rebuild the containers. Because of that, I added support for configuring the mode through a new environment variable, XDEBUG_MODE, too. This can be used when starting your Docker container, and/or in Compose.


Now PHP 8 is getting closer I have started to pay a little bit more attention to adding support for features, beyond making it compile. PHP 8 introduces named parameters, and also has a project for adding (and updating) names for internal functions. Xdebug's tracing and logging already showed variable names for user-defined functions, and I've now adding support of doing that for built-in functions and methods as well.

Showing argument names in Xdebug 2 is controlled through setting xdebug.collect_params to 4. In Xdebug 3 I have removed this setting altogether, and argument names are now always visible if possible.

My focus in September is to add support for the rest of PHP 8's features and capabilities as well.

Xdebug Cloud

The only time I spend in August on Xdebug Cloud is some further conversations with JetBrains. I am going to work on Xdebug Cloud when these conversations move along a little further.

If you want to be kept up to date with Xdebug Cloud, please sign up to the mailinglist I'll let you know as soon as something can be tried-out.

Business Supporter Scheme and Funding

In August, no new supporters signed up.

If you, or your company, would also like to support Xdebug, head over to the support page!

Besides business support, I also maintain a Patreon page and a profile on GitHub sponsors.


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