I got the following exception in my page:
Fatal error: Call to a member function someFunction() on a
non-object in seomfile.php on line 15
My code near line 15 is:
try
{
return getObject()->someFunction(); // line 15
}
catch(Exception $e) { }
I know getObject() returns null, but why isn't the try block catching it?
PHP mixes Exceptions and Errors. You could use set_error_handler() to throw an exception on error.
You can try to use something like this:
try {
$object = getObject();
If (!is_object($object)) {
throw new Exception();
}
return $object->someFunction();
catch (Exception $e) {
}
Because it's not an exception, it's a standard old-fashioned error.
Related
I have the following situation:
try {
DB::beginTransaction();
$task = new Task();
$task->setTracker("");
//thrown \Symfony\Component\Debug\Exception\FatalThrowableError
DB::commit();
}catch (\Exception $e){
DB::rollBack();
Log::error($e);
//throw $e;
}
I am not entering to the catch area.
Any idea why?
update
This is the error thrown:
[Symfony\Component\Debug\Exception\FatalThrowableError]
Type error: Argument 1 passed to App\Models\Task::setTracker() must be an instance of Carbon\Carbon, integer given, called in /var/www/app/Services/ShareLogic.php on line 60
and will not be catched
Thanks
Catching Throwable did the trick.
Have no idea why?
Anyone does?
It does not catch the exception because you are trying to catch \Exception which Symfony\Component\Debug\Exception\FatalThrowableError does not extend.
Instead try to catch the actual exception by importing it..
use Symfony\Component\Debug\Exception\FatalThrowableError;
And then you can do..
try {
//
} catch(FatalThrowableError e) {
//
}
Edit
Ok, so in addition to the above solution it seems PHP 7+ handles error a bit differently than PHP 5. So try this..
try {
//
} catch(Error $e) {
// This should work
} catch(Throwable $e) {
// This should work as well
}
Symfony's Debug component is much more sophisticated in order to log and report all kinds of errors but take look at this simple example (php 7.1.x):
<?php
class MyUncatchableError extends Exception {}
function myExceptionHandler($e) {
throw new MyUncatchableError('BANG: '.$e->getMessage());
}
set_exception_handler('myExceptionHandler');
$foo = true;
try {
$foo->modify();
} catch (Exception $e) {
echo 'nope';
} catch (MyUncatchableError $e) {
echo 'nope2';
}
What will be the outcome? Well:
Fatal error: Uncaught MyUncatchableError: BANG: Call to a member function modify() on boolean in /in/WJErU:6
Stack trace:
0 [internal function]: myExceptionHandler(Object(Error))
1 {main}
thrown in /in/WJErU on line 6
and you can't catch that exception because you should catch the original.. throwable here, which is Error for this kind of "error". You can catch it by catching "Error" class. And with PHP7 hierarchy it implements Throwable interface, that's why you can't catch it using Exception (because while Exception implements Throwable, Error is no an Exception - see: http://php.net/manual/en/language.errors.php7.php).
And this is true for PHP7+ because with 5.* there was no Throwable nor Error, and doing $foo->modify(); would just stop the script and return a Fatal Error. You can make your own error handler (set_error_handler) and throw an exception there (and Debug component does that for php 5.*) but this method does not work for Fatal Errors. Instead Debug component hooks into script shutdown and reads last error and throws FatalErrorException.
This description may not be completely accurate as I have't dug deeply into Symfony but you can get the idea here.
Here is my code:
try {
if ( condition 1 ) {
throw;
} else {
// do something
}
// some code here
if ( condition 2 ){
throw;
}
} catch (Exception $e) {
echo "something is wrong";
}
As you see, my catch block has its own error message, And that message is a constant. So really I don't need to pass a message when I use throw like this:
throw new Exception('error message');
Well can I use throw without anything? I just need to jump into catch block.
Honestly writing an useless error message is annoying for me.
As you know my current code has a syntax error: (it referring to throw;)
Parse error: syntax error, unexpected ';' in {path}
message parameter is optional in the Exception constructor. So if you don't have/want to put - just don't:
throw new Exception;
But you still must throw an instance of the Exception class (or a class that extends it), since it is a part of the php language syntax.
If you want all your exceptions to have the same message, you can extend it and define the message in your class:
class AmbiguousException extends Exception {
public function __construct($message = 'Something is wrong.', $code = 0, Exception $previous = null) {
parent::__construct($message, $code, $previous);
}
}
Then:
throw new AmbiguousException();
You can use the below throw everytime you need.
throw new Exception();
and catch will remain same as your code.
As stated in the PHP manual:
The thrown object must be an instance of the Exception class or a subclass of Exception. Trying to throw an object that is not will result in a PHP Fatal Error.
You can throw an exception without any message:
throw new Exception();
Perhaps something to help you from duplicating the same exception is as follows:
$e = new Exception('something is wrong');
try {
throw $e;
} catch (Exception $ex) {
echo $ex->getMessage();
}
You can create an instance with default message and then throw that instance.
$Exception = new Exception("some error message!");
try {
throw $Exception;
} catch (Exception $ex) {
var_dump($ex);
}
You cannot use the throw keyword on its own. However, you can use throw new Exception(); without specify the $message parameter, because it'll just fallback to the default message. Check out the Exceptions section in the PHP manual: http://php.net/manual/en/language.exceptions.extending.php
I am using Yii framework and have written code below. When there is no entry for a specific id it gives Error: Call to a member function delete() on a non-object which is a yii\base\ErrorException indicated in debug mode. The problem is that I am not able to catch this exception despite my inclusion of yii\base\ErrorException and specify it catch block. What is the problem here?
use yii\base\ErrorException;
try {
$model = BranchUser::findOne($_GET['id']);
$model->delete();
return $this->redirect(['index']);
} catch (ErrorException $e) {
return $this->redirect(['site/error']);
// Error, rollback transaction
throw $e;
// print_r($model->getErrors());
}
That is a fatal error and it is not possible to recover from it.
You should check that $model is something else than null before you try to use it.
if ($model === null) {
return $this->redirect(['site/error']);
}
Such errors are catchable in PHP 7.0, so that's good.
My code snippet is below - as you can see, I have a try-catch block, but inspite of this, I still get an uncaught exception that terminates the entire application. What am I missing?
try {
$cakeXml = simplexml_load_string($xml);
$parseSuccess = $cakeXml->xpath('//ParseSuccess');
} catch (Exception $ex) {
$response['parseSuccess'] = false;
$response['errors']['ParseError'] = 'An unknown error occurred while trying to parse the file. Please try again';
return $response;
}
2014-12-16 22:45:12 Error: Fatal Error (1): Call to a member function xpath() on a non-object
2014-12-16 22:45:12 Error: [FatalErrorException] Call to a member function xpath() on a non-object
If you read the error message more-carefully, you will see that it is not dieing on an Exception, but on a Fatal Error. A try/catch statement cannot catch a fatal error in PHP, as there is no way to recover from a fatal error.
As for solving this issue, your error is telling you $cakeXml is a non-object. One solution would be to do something like this.
try {
$cakeXml = simplexml_load_string($xml);
if (!is_object($cakeXml)) {
throw new Exception('simplexml_load_string returned non-object');
}
$parseSuccess = $cakeXml->xpath('//ParseSuccess');
} catch (Exception $ex) {
$response['parseSuccess'] = false;
$response['errors']['ParseError'] = 'An unknown error occurred while trying to parse the file. Please try again';
return $response;
}
DOMXPath methods i.e. xpath or evaluate does not throw exceptions. Hence, you will need to explicitly validate and throw the exception.
See below code snippet:
$xml_1= "";
try {
$cakeXml = simplexml_load_string($xml_1);
if ( !is_object($cakeXml) ) {
throw new Exception(sprintf('Not an object (Object: %s)', var_export($cakeXml, true)));
} else {
$parseSuccess = $cakeXml->xpath('//pages');
print('<pre>');print_r($parseSuccess);
}
} catch (Exception $ex) {
echo 'Caught exception: ', $ex->getMessage(), "\n";
}
I'm trying to catch a Laravel exception inside my library.
namespace Marsvin\Output\JoomlaZoo;
class Compiler
{
protected function compileItem($itemId, $item)
{
$boom = explode('_', $itemId);
$boom[0][0] = strtoupper($boom[0][0]);
$className = __NAMESPACE__."\\Compiler\\".$boom[0];
try {
$class = new $className(); // <-- This is line 38
} catch(\Symfony\Component\Debug\Exception\FatalErrorException $e) {
throw new \Exception('I\'m not being thrown!');
}
}
}
This it the exception I'm getting:
file: "C:\MAMP\htdocs\name\app\libraries\WebName\Output\JoomlaZoo\Compiler.php"
line: 38
message: "Class 'Marsvin\Output\JoomlaZoo\Compiler\Deas' not found"
type: "Symfony\Component\Debug\Exception\FatalErrorException"
The name of the class is voluntarily wrong.
Edit 1:
I noticed that if I throw an exception inside the try statement I can catch the exception:
try {
throw new \Exception('I\'d like to be thrown!');
} catch(\Exception $e) {
throw new \Exception('I\'m overriding the previous exception!'); // This is being thrown
}
The problem is that you're trying to catch a FatalErrorException in your class, but Laravel won't let a fatal error get back there; it terminates immediately. If your were trying to catch a different kind of exception, your code would work just fine.
You can catch and handle fatal errors with an App::fatal method in app/start/global.php, but that won't help you deal with the exception from within your library, or to handle it with any specificity. A better option would be to trigger a "catchable" exception (something from Illuminate, for instance), or to throw a custom one based on the condition that you are trying to check.
In your case, if your goal is to deal with undefined classes, here's what I would suggest:
try {
$className = 'BadClass';
if (!class_exists($className)) {
throw new \Exception('The class '.$className.' does not exist.');
}
// everything was A-OK...
$class = new $className();
} catch( Exception $e) {
// handle the error, and/or throw different exception
throw new \Exception($e->getMessage());
}