I have recently set up a new M2 MacBook Air and as usual, installed Homebrew and then installed PHP. Homebrew is always up to date, so it installed PHP 8.1 for me.

Again, as usual, I installed Xdebug using pecl install xdebug.

This whirrs and clicks for a while downloading and compiling the xdebug.so and then fails with:

rob@ardent ~ $ pecl install xdebug
downloading xdebug-3.1.5.tgz ...
Starting to download xdebug-3.1.5.tgz (232,070 bytes)

...

Build process completed successfully
Installing '/opt/homebrew/Cellar/php/8.1.8/pecl/20210902/xdebug.so'

PHP Warning:  mkdir(): File exists in /opt/homebrew/Cellar/php/8.1.8/share/php/pear/System.php on line 294
ERROR: failed to mkdir /opt/homebrew/Cellar/php/8.1.8/pecl/20210902

Investigating, I found that /opt/homebrew/Cellar/php/8.1.8/pecl is a symlink to /opt/homebrew/lib/php/pecl, however, this directory doesn’t exist. So to fix, I created the directory and installed Xdebug again:

mkdir /opt/homebrew/lib/php/pecl
pecl install xdebug

This time it worked:

rob@ardent ~ $ pecl install xdebug
downloading xdebug-3.1.5.tgz ...
Starting to download xdebug-3.1.5.tgz (232,070 bytes)

...

Build process completed successfully
Installing '/opt/homebrew/Cellar/php/8.1.8/pecl/20210902/xdebug.so'
install ok: channel://pecl.php.net/xdebug-3.1.5
Extension xdebug enabled in php.ini

A quick test shows that all is now as it should be:

rob@ardent ~ $ php -v
PHP 8.1.8 (cli) (built: Jul  8 2022 10:46:35) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.1.8, Copyright (c) Zend Technologies
    with Xdebug v3.1.5, Copyright (c) 2002-2022, by Derick Rethans
    with Zend OPcache v8.1.8, Copyright (c), by Zend Technologies