On keep-alive connections, we issue an RSET command in case of errors.
But that RSET command may fail, which causes the error information from
the original error to be replaced by the error information from the
RSET error, which isn't helpful in diagnosing the actual cause. To avoid
this problem, we need to extract the error information first, and only
issue the RSET command afterwards.
In case of errors, keep-alive SMTP connections are always reset, but
when the error happened while establishing the connection, trying to
reset the connection is pointless and just produces another error.
When using PHP's mail() function, and when there are no To-addressees (e.g. only BCC), then the DKIM-signature was not correct. There was a discrepancy between how mail() was called (empty $to) versus the DKIM-signature ('undisclosed-recipients:;').
The `$CharSet` property name as declared in the class starts with a capital, while there were two places in the code where the property was referred to as `$this->charSet`, which is a non-existent property.
In PHP 8.2, this is regarded as access to a dynamic property and will generate deprecation notices.
In effect, this meant that the `PHPMailer::parseAddresses()` method would be called with `null` as the value for the `$charset` parameter.
This `null` value would then subsequently be passed on to the PHP native `mb_internal_encoding()` function, which now didn't get the correct encoding.
This may have led to mail sending failures due to the address encoding being incorrect. If there are any bug reports open for this, it may be a good idea to evaluate whether they could be related to this bug.
Found by dseguy via Exakat.
Note: this issue was not flagged by the tests as the tests for the `PHPMailer::parseAddresses()` method, only test the method either with a valid value for encoding òr without the `$charset` parameter set, but not with an explicit `null` value..
As the `$charset` parameter for `PHPMailer::parseAddresses()` has a sensible default value and is not explicitly nullable, adding a test for this incorrect use of the method seems over the top.
I have, however, ensured that the non-nullability of the parameter is now documented for the method.
Refs:
* https://wiki.php.net/rfc/deprecate_dynamic_properties
* https://www.php.net/manual/en/function.mb-internal-encoding.php
Marcus Bointon
Björn Steinbrink
Darren Sim
sverpoorten
evan70
Darren Eberly
mortalys
MathiasReker
jrfnl
Julien BERNARD
Michael Newton
Peter Scopes