All voters must return an int.
https://github.com/symfony/symfony/blob/5.x/src/Symfony/Component/Security/Core/Authorization/Voter/VoterInterface.php#L38

Why do you return something else?

IMHO nothing should be fixed here

I think the problem is that if you make a mistake and return something that is castable ton an int (for example true instead of ACCESS_GRANTED) it will work in dev environment where it shouldn't, and the bug will only appear in production.

Thanks for all information in the issue description, that makes it very easy to trace the exact problem here.

I would propose the following solution:

1. Remove the : int type juggling indicator in the 4.4 branch
2. Deprecate not returning an int in 5.x. This can be done exactly like done in the Console component in 4.4:

   symfony/src/Symfony/Component/Console/Command/Command.php

   Lines 257 to 259 in aa5ec20

   	if (!\is_int($statusCode)) {
   	@trigger_error(sprintf('Return value of "%s::execute()" should always be of the type int since Symfony 4.4, %s returned.', static::class, \gettype($statusCode)), \E_USER_DEPRECATED);
   	}

3. Add an exception in 6.0, like in the Console component:

   symfony/src/Symfony/Component/Console/Command/Command.php

   Lines 258 to 260 in f0dfb9e

   	if (!\is_int($statusCode)) {
   	throw new \TypeError(sprintf('Return value of "%s::execute()" must be of the type int, "%s" returned.', static::class, get_debug_type($statusCode)));
   	}

Are you willing to create a PR for (1) and (2)?

There is no such declaration in VoterInterface

There is, in the PHPdoc:

@wouterj thx for the response. I will do exactly the way you suggested. today in the late afternoon(CET time zone).

@jvasseur and @lyrixx that is correct. However, the dev environment should escalate errors, not hide them.

@adeptofvoltron yes, but erroring in this case would be a BC break, that why we can only deprecate it for now.