[Console] add support for catching \Throwable errors

[lyrixx]

Q	A
Branch?	6.4
Bug fix?	no
New feature?	yes
Deprecations?	no
Tickets	Fix #46596
License	MIT
Doc PR

[javaDeveloperKid]

Historical question: were all the try..catch blocks in the Symfony code base modified from \Exception to \Throwable after the latter had been introduced? I can still see blocks that catch \Exception and I wonder if this is just an oversight or there is a reason behind this.

[maxbeckers]

LGTM

[chalasr]

The broken test covers the behavior for which we cannot just do this unfortunately. Check #22690 for background (tldr errors must keep reaching custom error handlers).

[lyrixx]

Hmm, When using the component directly without the error handler, a command can crash badly :/

What about adding a flag to choose if we should handle throwable or not?

[chalasr]

Sounds like a good idea 👍

[nicolas-grekas]

The very lines before the try/catch setup a global error/exception handler, why does this crash badly as you write, while we have this in place?

[lyrixx]

@nicolas-grekas let's say you are building a project that run commands, when someone makes an error in the command, it will produces theses outputs:

Without this patch:

>/tmp/foobar foobar  hello
PHP Fatal error:  Uncaught Error: Call to undefined function hello2() in /tmp/foobar/foobar.php:9
Stack trace:
#0 [internal function]: hello()
#1 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Command/TaskCommand.php(152): ReflectionFunction->invoke()
#2 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Command/Command.php(326): Foobar\Console\Command\TaskCommand->execute()
#3 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(1063): Symfony\Component\Console\Command\Command->run()
#4 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Application.php(57): Symfony\Component\Console\Application->doRunCommand()
#5 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(320): Foobar\Console\Application->doRunCommand()
#6 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Application.php(45): Symfony\Component\Console\Application->doRun()
#7 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(174): Foobar\Console\Application->doRun()
#8 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/ApplicationFactory.php(28): Symfony\Component\Console\Application->run()
#9 /home/gregoire/dev/github.com/jolicode/foobar/bin/foobar(14): Foobar\Console\ApplicationFactory::run()
#10 {main}
  thrown in /tmp/foobar/foobar.php on line 9

Fatal error: Uncaught Error: Call to undefined function hello2() in /tmp/foobar/foobar.php:9
Stack trace:
#0 [internal function]: hello()
#1 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Command/TaskCommand.php(152): ReflectionFunction->invoke()
#2 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Command/Command.php(326): Foobar\Console\Command\TaskCommand->execute()
#3 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(1063): Symfony\Component\Console\Command\Command->run()
#4 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Application.php(57): Symfony\Component\Console\Application->doRunCommand()
#5 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(320): Foobar\Console\Application->doRunCommand()
#6 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/Application.php(45): Symfony\Component\Console\Application->doRun()
#7 /home/gregoire/dev/github.com/jolicode/foobar/vendor/symfony/console/Application.php(174): Foobar\Console\Application->doRun()
#8 /home/gregoire/dev/github.com/jolicode/foobar/src/Console/ApplicationFactory.php(28): Symfony\Component\Console\Application->run()
#9 /home/gregoire/dev/github.com/jolicode/foobar/bin/foobar(14): Foobar\Console\ApplicationFactory::run()
#10 {main}
  thrown in /tmp/foobar/foobar.php on line 9

With this patch (there is color, and Symfony styling):

>/tmp/foobar foobar  hello

In foobar.php line 9:
                                       
  Call to undefined function hello2()  
                                       

hello

And if the developer wants more output, they can run the same command with -v flags

[lyrixx]

Very simple reproducer :

take only symfony/console, then run:

<?php

require __DIR__.'/vendor/autoload.php';

use Symfony\Component\Console\SingleCommandApplication;

(new SingleCommandApplication())
    ->setCode(function () {
        echo "AAA";
        foobar();
    })
    ->run()
;

[lyrixx]

I have rebased the PR, restored BC, added a new flag to handle errors, and added some tests.

I think it's ready ✅

[chalasr]

Thank you @lyrixx.

[chalasr]

@Seldaek FYI

[Seldaek]

@chalasr thanks for the ping, see composer/composer@f4738d97b (I guess that's why you pinged me :)