Hey!

I see that this is your first PR. That is great! Welcome!

Symfony has acontribution guide which I suggest you to read.

In short:

• Always add tests
• Keep backward compatibility (seehttps://symfony.com/bc).
• Bug fixes must be submitted against the lowest maintained branch where they apply (seehttps://symfony.com/releases)
• Features and deprecations must be submitted against the 6.1 branch.

Review the GitHub status checks of your pull request and try to solve the reported issues. If some tests are failing, try to see if they are failing because of this change.

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I am going to sit back now and wait for the reviews.

Cheers!

Carsonbot

The change has been done on purpose, see#37888 for the explanation.

I'm sorry, but I don't understand why in#37888 this change is made. What is wrong with setting the sender via the return path if it is set? Btw other mailers do it this way.

In my opinion this will be correct -- first: "sender", second: "return-path", last: "from"

private static function getSenderFromHeaders(Headers $headers): Address    {        if ($sender = $headers->get('Sender')) {            return $sender->getAddress();        }                if ($return = $headers->get('Return-Path')) {            return $return->getAddress();        }                if ($from = $headers->get('From')) {            return $from->getAddresses()[0];        }        throw new LogicException('Unable to determine the sender of the message.');    }