No need to echo db exception

[kathysledge]

No description provided.

[samdark]

Why?

[kathysledge]

$exception contains a raw exception message from the database server, and that exception also seems to be handled fine like any other exception:

See the text printed here underneath the standard error screen (in prod. mode).

[cebe]

how did you get this output? looks a bit like yii 1.1 error page...

[kathysledge]

When no errorAction is set in the errorHandler config, the following view file is rendered: yiisoft/yii2/views/errorHandler/error.php. That's the one in the pic.

BTW, a full stacktrace is shown in debug mode, with a longer version of the exception being echoed at the end of the page (because of echo $exception).

[samdark]

echo was added in #1946

[samdark]

I've verified that in current code it seems to work just fine w/o echo. @cebe any comments?

[kidol]

The echo part is intended for writeSession() only. If some database exception happens before writeSession() (and the exception is handled correctly), then writeSession() will be called anyhow because of register_shutdown_function([$this, 'close']); in Session::init().

This works correctly though:

Yii::$app->session->get('test');
sleep(5); // shutdown db server here
Yii::$app->session->set('test', 123);

[samdark]

If there's no DB table it works correcty as well i.e. exception is handled properly.

[kidol]

@samdark Yes it's handled, but not in writeSession(). You must test db exception that's thrown in writeSession() to see the need for echo().

Use this:

Yii::$app->session->get('test');
sleep(5); // shutdown db server here
Yii::$app->session->set('test', 123); // will cause exception in writeSession
exit;

This outputs the exception as string without rendering any html.

And if you do

// Shutdown db server here
Yii::$app->session->open();
exit;

You get rendered html + the string at bottom.

Dirty fix could be:

// Only echo and log if we haven't processed an exception yet
if (Yii::$app->errorHandler->exception === null) {
   $exception = ErrorHandler::convertExceptionToString($e);
   // its too late to use Yii logging here
   error_log($exception);
   echo $exception;
}

@cebe Is there really no way to properly handle exceptions thrown in writeSession()? For example, looking at symfony they seem to throw: https://github.com/symfony/symfony/blob/2.8/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php#L377

[cebe]

@cebe Is there really no way to properly handle exceptions thrown in writeSession()? For example, looking at symfony they seem to throw: https://github.com/symfony/symfony/blob/2.8/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php#L377

see http://us3.php.net/manual/en/function.session-set-save-handler.php#refsect1-function.session-set-save-handler-notes

however this issue has been worked around by fa845ee already. Closing this PR.

[cebe]

related to #11726