what does "platform settings: fail" mean on composer?

Question

I'm looking for some pointers on how to start trying to workout what the problem is with my composer installation.

C:\xampp>composer diagnose
Checking composer.json: OK
Checking platform settings: FAIL

The xdebug extension is loaded, this can slow down Composer a little.
Disabling it when using Composer is recommended, but should not cause issues beyond slowness.
Checking git settings: OK
Checking http connectivity: OK
Checking disk free space: OK
Checking composer version: OK

C:\xampp>composer self-update
You are already using composer version 1e27ff5e22df81e3cd0cd36e5fdd4a3c5a031f4a.

Answer 1

It already tells you why checking platform settings fails: It is because of the xdebug extension which is loaded. But this should not cause any issues beyond slowness.

If you feel your composer to be slow and you don't need xdebug you can disable it. Here is how you do that: https://stackoverflow.com/a/8754934/3219613