Symfony version(s) affected

4.4.34

Description

https://github.com/symfony/process/blob/5.3/Process.php#L342

In the start() method as of 4.4.34 we are now getting an Array to String conversion ErrorException.

This appears to also be present with the latest Laravel Framework update which is what caused us to start getting this issue. Every thing that uses the Symfony start() method is now throwing this error so its no one specific command causing it.

Seems to be something in the envs is being allowed through as an array. Previous 4.4.34 maybe they were not being stripped, or maybe a change in 4.4.34 allowed an array to end in the envs variable.

How to reproduce

start() symfony process method given a command line with arguments. In our case one example command was:

exec '/home/.nvm/versions/node/v12.3.1/bin/node' '/var/www/html/our-script.js' ''\''string_a'\''' ''\''string_b'\'''

$process = new Process(
            [
                $node,
                base_path() . '/our-script.js',
                escapeshellarg($string_a),
                escapeshellarg($string_b)
            ]
        );

where string_a and string_b are definitely strings ;)

Possible Solution

No response

Additional Context

Likely related to this PR that went in to 4.4.34:

#44070