Laravel PackageManifest.php: Undefined index: name

I had the same problem, I just execute the command:

composer update

this will updated the composer.lock file. After that worked like a charm.

As a temporary fix, try this, it worked for me, in the following file:

vendor/laravel/framework/src/Illuminate/Foundation/PackageManifest.php

Find line 116 and comment it:

$packages = json_decode($this->files->get($path), true);

Add two new lines after the above commented line:

$installed = json_decode($this->files->get($path), true);
$packages = $installed['packages'] ?? $installed;