Xdebug Update: September 2020

London, UK

Tuesday, October 6th 2020, 09:25 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.

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In September, I worked on Xdebug for about 60 hours, with funding being around 70 hours. I worked mostly on the following things:

Xdebug 3

This month I mostly focussed on getting Xdebug 3 in shape for a first beta release, with all the new configuration names in place. There are now only a few tasks before I can release Xdebug 3.0.0beta1. I plan to release this around PHP 8.0RC2.

The main changes that I made was to rename the following four configuration settings, mostly to get "rid" of the remote naming:

• xdebug.remote_host → xdebug.client_host

• xdebug.remote_port → xdebug.client_port

• xdebug.remote_connect_back → xdebug.discover_client_host

• xdebug.remote_addr_header → xdebug.client_discovery_header

I hope that these new names are easier to explain, and of course the upgrade guide explains the changes too.

PHP 8

Although RC1 of PHP 8 is released today, there are still numerous items still in flux. In September there were various changes due to PHP 8's new named parameters. This mostly has an effect on Xdebug's tests, where these names are exposed as part of tracing or debugging tests. Because there are still changes, I am delaying Xdebug 3.0.0beta1 until PHP 8.0RC2.

Other API changes also meant that I had to make changes in Xdebug. Most notably related to code coverage, where PHP 8 will emit fewer Op codes and now (finally!) creates ASSIGN operations on the correct line (which makes Xdebug's breakpoint resolving feature less necessary).

Releases

There were two Xdebug releases in September. 2.9.7 changes the step debugger to set up TCP Keepalive probes. This results in better time-out management in case network connections between Xdebug and an IDE drops.

Unfortunately this patch caused compilation issues on FreeBSD where some OS specific flags are different (but the same as OSX, which Xdebug did handle correctly). A fix for this, as well as a fix for path/branch coverage with foreach loops resulted in the 2.9.8 release. I expect to create one more release related to the TCP Keepalive addition as the current release still does not compile for AIX.

Beyond this, I do not expect any more release of the Xdebug 2.9 series unless security or crash bugs are present.

Xdebug Cloud

Beyond fixing an off-by-one error in host name generation, I did not write any code for Xdebug Cloud. However, work is ongoing on a web site, and JetBrains is also working on supporting Xdebug Cloud in PhpStorm. Reports state that a prototype is now working. With one IDE soon to support Xdebug Cloud I am also sharing the protocol changes with other IDE/debug client authors before I make it part of the DBGp specification.