[Console] Help command reports wrong usage in a single command application

[Chi-teck]

Symfony version(s) affected: 4.1.1

Description
The usage section of help command output should not print command name as it is not supported.

How to reproduce

• Create a simple single command application using this example from documentation.
• Save it to ./bin/test.php file.
• Run the script with some argument (./bin/test.php foo) and make sure it works as expected.
• Run the script as it suggested by help command (./bin/test.php echo foo).
• The following error should appear: Too many arguments, expected arguments "foo".

[blixit]

@Chi-teck I don't understand your issue. What behavior are you expecting ?

[Chi-teck]

@blixit I expect that help command prints correct command usage. Currently of you copy/paste usage from help output you will get the error mentioned above.

[xabbuh]

Status: Reviewed

[dmanners]

As far as I can see the issue happens because of the resetting of the arguments to empty in the getDefinition method: https://github.com/symfony/console/blame/master/Application.php#L305

After playing around with the example and removing this line the expected results happen.

That being said I am not sure really sure why this resetting of arguments was done in the first place. I would be happy to make a PR for this change if people think it is the right approach.

[chalasr]

Fixed in #29617.