Today I was getting introduced to Dart myself. At a point while playing with it, something was going wrong. Later I found that it was nothing but I forgot to put return statement in a function so null was set to the variable that was supposed to get value from that function.
At that point I was thinking, in Java it would be caught as error in the very first place. Why C/C++ or the new Dart don't add this feature? Does this feature slows the code down at a large scale? Or there are any other technical reasons behind this?
Every method returns a value, and if there is no return it is null.
However it looks like this some enhancements could be done in the future. See issue 73 : Missing return statement does not trigger warning or error and issue 13373 : Can get the editor to warn when there is no explicit return for a function returning a type.
Related
I'm a bit new to laravel, but I'm experienced in Php.
In previous works, I set a mecanism that allowed me to be informed when nearly any problem occurred on the server:
I got full stack
precise PHP error messages
for nearly all king of errors
a mail sent to me
So when I began to work with laravel, I tried to do the same things, and achieved:
full stack
a mail sent to me
But I can't have meaningful error in all case. One example:
$store = Store::create(...)
In this line I forget to specify the namespace (\App\Store::create), and I get those error messages:
first:
FatalThrowableError ; Type error: Argument 1 passed to App\Http\Controllers\User::create() must be an instance of Illuminate\Http\Request, array given, called in /var/www/html/laravel/blog/app/Http/Controllers/User.php on line 94
second:
ErrorException ; Trying to get property of non-object in VerifyCsrfToken.php (line 156)
third:
FatalThrowableError ; Type error: Argument 1 passed to Illuminate\Session\Middleware\StartSession::addCookieToResponse() must be an instance of Symfony\Component\HttpFoundation\Response, array given, called in /var/www/html/laravel/blog/vendor/laravel/framework/src/Illuminate/Session/Middleware/StartSession.php on line 72
I understand that laravel is a complex framework but I can't figure why it produces this errors, and how I can have more useful errors (as as it is I can only know that "something is bad").
Has someone an idea ?
ยน There is some errors that Php prefers to keep to himself (in its logs) :-)
When you start a new Laravel project, error and exception handling is
already configured for you. The App\Exceptions\Handler class is where
all exceptions triggered by your application are logged and then
rendered back to the user.
https://laravel.com/docs/5.4/errors
I recommend you to dive into the official docs and into your App\Exceptions\Handler.
Maybe you are looking for report and render methods in that class.
I finally cornered the problem and I learned a lot.
I thank for their benevolence #Don't Panic and #Vitalmax !
The error was that I forgot that PHP namespaces are case insensitive: in my post I cleaned a bit the code as I knew that it didn't stick to the code's conventions (a controller's name must begin with a capital letter). Originally my controller name was user and the faulty code was:
$user = User::create(...)
As you can guess PHP believed that I wanted to call user::create (as I have such a method in my controller) and not User::create (as I wanted).
What I learned:
don't alter the code when asking for help
Laravel use a cache system that can get in the way of the debugging (see a question that I asked on laracast's forum )
take more time to read the error message; I know this rule but I keep doing otherwise
Going from Joomla 2.5 to 3.0 with my extension, I'm struggling with how to do the DB error handling (since GetErrorNum is deprecated, see also Joomla! JDatabase::getErrorNum() is deprecated, use exception handling instead).
The way that seems to be the one to go according to the question linked above, is to add the following code for each db->query() code:
if (!$db->query()) {
throw new Exception($db->getErrorMsg());
}
In my opinion, that makes DB error handling more awkward than it was before. So far, I simply called a checkDBError() function after a DB call, which queried the ErrorNum and handled any possible error accordingly.
That was independent from how the DB query was actually triggered - there are different ways to do that, and different results on an error: $db->loadResult() returns null on error, $db->query() returns false. So there will now be different checks for different DB access types.
Isn't there any generic way to handle this, e.g. a way to tell Joomla to throw some exception on DB problems? Or do I have to write my own wrapper around the DatabaseDriver to achieve that? Or am I maybe missing something obvious?
Or should I just ignore the deprecation warning for now and continue with using getErrorNum()? I'd like to make my extension future-proof, but I also don't want to clutter it too much with awkward error handling logic.
Just found this discussion: https://groups.google.com/forum/#!msg/joomla-dev-general/O-Hp0L6UGcM/XuWLqu2vhzcJ
As I interpret it, there is that deprecation warning, but there is no proper replacement yet anyway...
Unless somebody points out any other proper documentation of how to do it in 3.0, I will keep to the getErrorNum method of doing stuff...
Get getErrorNum() function will solve your problem....
$result = $db->loadResult();
// Check for a database error.
if ($db->getErrorNum())
{
JFactory::getApplication()->enqueueMessage($db->getErrorMsg());
return false;
}
I just migrated my language service from VS2008 to VS2010. Everything works fine except for one important thing: I no longer get LanguageService.ParseSource invoked for ParseReason.Check. It do get a single invoke after opening a file. But after editing code, it no longer gets invoked.
Any ideas what could be causing that?
I also migrated a language service from 2008 to 2010. Can you check if you've fallowed all of these steps?
http://msdn.microsoft.com/en-us/library/dd885475.aspx
I didn't have to do anything else, which I verified by diffing the important files in our depot before and after the change.
I don't know if you ever figured your question out, but have you tried making sure that your Source class' LastParseTime is set to 0 when creating it? I seem to recall some issues with Check not happening unless you manually set LastParseTime to 0 when creating your Source object.
Protip: If you use .NET Reflector, you can disassemble all of the base classes for the LanguageService framework and get a pretty good understanding of how it all works under the hood. The classes you'd be interested in live in Microsoft.VisualStudio.Package.LanguageService.10.0.dll, which should be installed in the GAC. I've found this to be unimaginably helpful when trying to figure out why things weren't working in my own Language Service, and being able to step through the source code in the debugger mitigates almost all the pain of working with these frameworks!
When your Source object is initialized, it starts off with a LastParseTime of Int32.MaxValue. The code that causes fires off a ParseRequest with ParseReason.Check checks the LastParseTime value to see if the time since the last change to the text is less than the time it takes to run a parse (or the CodeSenseDelay setting, whichever is greater).
The code that handles the response from ParseSource is supposed to set the LastParseTime, but as far as I can tell, it only does that if the ParseReason is Check.
You can get around this issue by setting Source.LastParseTime = 0 when you initialize your Source. This has the side-effect of setting CompletedFirstParse to true, even if the first parse hasn't finished yet.
Another way to fix this issue is to override Source.OnIdle to fire off the first call to BeginParse() This is the way I would recommend.
public override void OnIdle(bool periodic)
{
// Once first "Check" parse completes, revert to base implementation
if (this.CompletedFirstParse)
{
base.OnIdle(periodic);
}
// Same as base implementation, except we don't check lastParseTime
else if (!periodic || this.LanguageService == null || this.LanguageService.LastActiveTextView == null || (this.IsCompletorActive) || (!this.IsDirty || this.LanguageService.IsParsing))
{
this.BeginParse();
}
}
Does anyone have the faintest idea what this error means please and how to resolve it? All my research is drawing a blank, I can see how to set it on MSDN but it doesn't explain it in a way that explains to me what the issue is. If I remove some of my LINQ queries to set viewbag items then it seems to resolve it but the moment I set new ones and pass them into my view to generate a mail for MVCMailer it comes back. Not sure if its a viewbag issue or simply that I am calling too many linq queries to generate them to pass to the view.
I am very stuck (again)..........
Cheers,
Steve.
DbLimitExpression requires a collection argument.
Parameter name: argument
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentException: DbLimitExpression requires a collection argument.
Parameter name: argument
An example of the code is:
var VBSalutation = from A in context.Salutations
where A.SalutationId == policytransaction.SalutationId
select A.SalutationName;
ViewBag.Salutation = VBSalutation.FirstOrDefault();
This is repeated for various parameters and then passed to the view.
Well, I faced a similar problem and solved it. Problem was in WHERE clause: data type of left side equal operator (=) sign was not matching with data type of right side. So in your scenario:
where A.SalutationId == policytransaction.SalutationId
SalutationID of A might be an INT and SalutationId of policytransaction might be a string (This is how it was in my case).
I solved it by assigning policytransaction.SalutationId to an Int variable and using it:
int myIntVariable = Convert.ToInt16(policytransaction.SalutationId);
...//some code here
where A.SalutationId == myIntVariable;
Please also note that you cannot directly cast your variables directly in Linq else you'll get an error "LINQ to Entities does not recognize the method". You'll have to use a temp variable and then apply the where clause.
Try ViewBag.Salutation = VBSalutation.SingleOrDefault();
I am trying to make firebug break when an error is detected. Specifically, I have some internal checks in my code, like assertions, that I want firebug to stop on when they fail. I have tried a few different ways and wondered what other people do? Here are the ways I have tried:
Put in some invalid code so that if errors out:
function assert(value) { if(! value) dbgbreak(); } // Fails because dbgbreak not defined
This works somewhat, but does not stop the code in such a way that I can see the stack or examine local variables.
Have it throw an exeption:
function assert(value) { if ! value) throw AssertExecption(); }
This is prettier, but still when I track exceptions I can't see the stack or the locals
Put a breakpoint on the assert failure. This works, however, it means everytime I run my code I have to manually put in a bunch of breakpoints.
What do other people do in terms of working with the debugger and asserts, and similar consistency checks?
Have you tried throwing down the "debugger" keyword in your script where you want it to stop?
On the console tab there is a button for breaking on all errors. Turn that on, and it will automatically break when an error occurs.
http://getfirebug.com/wiki/index.php/Console_Panel#Break_On_All_Errors