PHP composer xdebug warning
To fix this, prior to PHP 7 people would suggest to comment out the extension from your php.ini file. However, in PHP 7 they are no longer in there.
Instead, we use the phpdismod command.
sudo phpdismod -s cli xdebug
The -s flag tells it to disable Xdebug for the CLI SAPI (/etc/php/7.0/cli) and not FPM.
And just like that, the warning message should be gone. No need to restart PHP.
In addition to this, there is a plugin that downloads packages in parallel to speed up the installation process.
I do not want to disable xdebug when I am developing. Just wanted to confirm that running xdebug in dev environment should have no impact on the composer installing libraries/performance of the app on the production server.
There is a huge impact of just loading Xdebug. It slows the Composer run down by 3x or 4x, even when the profiling feature is not enabled.
In other words: xdebug is invaluable for debugging, but increases the memory used and processing time of Composer.
How to disable Xdebug for Composer runs?
My suggestion is to write a little invocation helper for running Composer.
The helper is a bash or batch script calling PHP with a custom php.ini, especially configured for Composer. Lets call it: php.ini-composer.
You could copy your current php.ini and adjust it for the Composer run, by removing xdebug or commenting it out, like so: ;zend_extension = "/path/to/my/xdebug.so".
While you are at it: setting memory_limit=-1 is helpful, too.
The full command looks like so on Windows: php.exe -c php.ini-composer composer.phar %*
Just clone the idea for a bash script.
And you may find the full answer to your question in the Composer FAQ.
https://getcomposer.org/doc/articles/troubleshooting.md#xdebug-impact-on-composer
It was added/updated just a few hours ago.
Some alternatives (instead of using seperate ini file) are also mentioned here.
Like with web scripts, expect CLI scripts to run slower as well.
If you need the added runtime performance, you can disable XDebug on CLI only. Set your PHP installation so that it uses different ini files for CLI and your server, as this answer suggests.
Modern versions of Composer can work around having XDebug enabled by default for the CLI SAPI. It spawns a new PHP process with the XDebug extension disabled in case it is detected.
You can disable this behaviour by setting the following environment variable:
COMPOSER_ALLOW_XDEBUG=1
Found this in the documentation: https://getcomposer.org/doc/articles/troubleshooting.md#xdebug-impact-on-composer