Questions related to handling errors and exceptions. According to Wikipedia, Exception handling is the process of responding to the occurrence, during computation, of exceptions – anomalous or exceptional events requiring special processing – often changing the normal flow of program execution. It ...

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How should I handle exception that *should* never be thrown? [duplicate]

What is the best way to handle errors that shouldn't ever happen? My current way to do this is to throw an exception if the 'thing that shouldn't happen' does happen, like so: /* * Restoring from a ...
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1answer
247 views

Error Handling when no access to Visual Studio or application start point

I've recently joined a project where we are extending the functionality of an external application that our company has bought. It is an Office Add-In with an admin console that allows you to create ...
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1answer
186 views

Functions returning either “OK” or “error message” instead of procedures

I have joined writing middle-size multi-purpose database application as co-lead. It currently has about 150 tables (and growing) and overall functionality you can imagine as very small ERP. At many ...
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1answer
83 views

Automating form error handling

I'm not sure if I'm being clever or making things more difficult. I'm working within a custom MVC framework, and within some of my "views" which contain forms I'm preserving input and styling errors ...
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1answer
112 views

Invalid data returned, which HttpCode to return?

My web application calls a third party API. If I successfully call the API but invalid data is returned which cannot be processed by my system what is the most appropriate HttpCode to return to the ...
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0answers
85 views

Check some value between each function call

Can you recommend a nice way of checking a particular value between calls to a set of functions? E.g. something like this in Python (might not be terribly 'Pythonic'): self.error_code = 0 # this ...
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1answer
59 views

Partial recovery from an Exception [duplicate]

I have seen Exception Handling blocks that they were throwing the recently caught Exception in the catch block. Something like: } catch ( Exception $e ) { // Do some recovery here ...
3
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2answers
4k views

Python - assert vs if & return

I am writing a script that does something to a text file (what it does is irrelevant for my question though). So before I do something to the file I want to check if the file exists. I can do this, no ...
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5answers
433 views

Fail-fast paradigm overheads

Fail-fast seems like a right way since it simplifies bug detection. But it's a harm for performance cause of multiple checking the same thing at several levels of the system. Simple example. There is ...
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3answers
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Authoritative sources for exception handling best practices [closed]

My work place suffers from a bad case of the Pokemon Exception Handling anti-pattern with constructs like the following splattered across the code base: try { ... } catch (Exception ex) { // ...
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2answers
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What's the difference between robustness and fault-tolerance?

Systems / programs / distributed algorithms / ... are often described with the predicate robust or fault-tolerant. What is the difference? Details: When I google for +robust +"fault-tolerant", I ...
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4answers
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Is error suppressing bad practice?

On a SO question I asked here about some code I was unsure about, someone replied "BTW, horrible code there: it uses the error suppressing symbol (@) a lot." Is there a reason why this is bad ...
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2answers
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How to Implement Error Handling [closed]

Even though I've programmed on a professional level for some years I still do not fully understand error handling. Although my applications work fine, the error handling isn't implemented at a ...
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3answers
6k views

Best Practices To Create Error Codes Pattern For an Enterprise Project in C# [closed]

I'm working on an enterprise project which will be deployed in many SMBs and Enterprises. The support for this project would be struggling and so I want to create a coding pattern for errors (Like ...
1
vote
1answer
260 views

How do I go about debugging a PHP error?

I am coming from .NET to PHP. I am playing around with a long file written by someone else (called "cryptographp.inc.php"). It builds and returns an image to the browser. I want to show the image ...
57
votes
16answers
22k views

How to handle divide by zero in a language that doesn't support exceptions?

I'm in the middle of developing a new programming language to solve some business requirements, and this language is targeted at novice users. So there is no support for exception handling in the ...
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4answers
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Exceptions vs ErrorCodes when working with devices

Out team is at the cusp of a new project. One of the components at the boundary of the system is the component which interacts with a printer through an external COM component (referenced as a usual ...
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votes
3answers
183 views

Is there a good reason not to display error messages to users?

Windows 8 seems to have chosen to silently shutdown applications that misbehave, there is no message informing the user something bad happened and no information on why the application closed. I ...
2
votes
1answer
85 views

How do I output an error when I'm determining how to output an error?

I've written an API which can be configured to signal errors in different ways (return values, debugging messages, or exceptions). I've got a check in place when the API is first initialized to see ...
7
votes
4answers
1k views

Best Practice: Should error messages be handled by the API or by the App?

I am designing an application that interacts with a RESTful API. When returning error messages like Unable to sign up user Should the error message be generated by the app? or by the API? I am ...
0
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1answer
173 views

Is there a standard for Error Codes?

I've created a gateway which receives a POST from cUrl on one system which is a well-formed XML string. After processing the gateway sends back a response XML. All the fields in the XML are required ...
2
votes
4answers
204 views

How do you hide error handling? [duplicate]

Many people consider exceptions to be a problem because they create invisible paths through your code. For example in this snippet: function writeToFile(text, filename): filehandle = open(filename) ...
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2answers
2k views

Nested Try Catch Error Handling with Log Files?

Best practice question for error handling in C#? In our system we will be writing out files, and with each file they will have a corresponding error file. The error file will get written every time ...
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14answers
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Why is 0 false?

This question may sound dumb, but why does 0 evaluates to false and any other [integer] value to true is most of programming languages? String comparison Since the question seems a little bit too ...
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2answers
231 views

Are error codes wrong in SQL queries too?

I have an SQL query which does several things at once¹: it does multiple checks and then, if the checks pass, updates some data. Without entering in the domain-specific details, here's an imaginary ...
3
votes
3answers
364 views

How can I ensure a method is called only once when using a API?

In general, if I am using an API whose methods have side-effects that I only want to occur once, how can I guarantee that my own application only calls them once even if an error occurs before it can ...
3
votes
3answers
515 views

How should my web application handle common errors such as incorrect password, session timeout, etc.?

How should my web application handle common errors such as incorrect password, session timeout, etc.? I have a class called Hotmail that contains various method such as login, logout etc. To ...
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6answers
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How safe are hidden AJAX requests that fake performance?

What is a hidden AJAX request? I've noticed an increase in the usage of hidden AJAX requests designed to make a user's action appear to happen immediately. I'll refer to this type of AJAX request as ...
3
votes
2answers
282 views

Error checking in actor-based paradigm

I have an existing Scala application that I am trying to refactor in order to use Akka. One of the problems I have is how to manage error-checking in actor-based applications. Usually error-checking ...
59
votes
11answers
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I've been told that Exceptions should only be used in exceptional cases. How do I know if my case is exceptional?

My specific case here is that the user can pass in a string into the application, the application parses it and assigns it to structured objects. Sometimes the user may type in something invalid. ...
0
votes
2answers
172 views

Custom error handling

I'm trying to figure out the best way to handle custom errors in my application. Option 1: if(expr) { } else { $_SESSION['error'] = "Some message describing the error"; } Option 2: if(expr) { ...
3
votes
1answer
200 views

Returning status code where one of many errors could have occured

I'm developing a PHP login component which includes functions to manipulate the User object, such as $User->changePassword(string $old, string $new) What I need some advice with is how to return a ...
0
votes
1answer
850 views

PHP MVC error handling, view display and user permissions

I am building a moderation panel from scratch in a MVC approach and a lot of questions cropped up during development. I would like to hear from others how they handle these situations. Error ...
2
votes
2answers
108 views

How does one handle an incorrect resource file?

I'm starting the parser that will handle one of the key features of my app and realizing exactly who easy it would be for me to screw up a resource file that is provided to the application. For ...
3
votes
3answers
141 views

handling a GET error properly

I have a website that takes two primary get strings: ?type=GAME&id=SomeGameID ?type=SCENARIO&id=SomeScenarioID for reasons unknown, I have recently begun receiving requests for erroneous ...
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4answers
178 views

What is the best way to go about testing that we handle failures appropriately?

we're working on error handling in an application. We try to have fairly good automated test coverage. One big problem though is that we don't really know of a way to test some of our error handling. ...
4
votes
1answer
175 views

Why is nesting or piggybacking errors within errors bad in general?

Why is nesting or piggybacking errors within errors bad in general? To me it seems bad intuitively, but I'm suspicious in that I cannot adequately articulate why it is bad. This may be because it is ...
40
votes
10answers
4k views

Why are exceptions considered better than explicit error testing? [duplicate]

Possible Duplicate: Defensive Programming vs Exception Handling? if/else statements or exceptions I often come across heated blog posts where the author uses the argument: "exceptions vs ...
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7answers
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Should a stack trace be in the error message presented to the user?

I've got a bit of an argument at my workplace and I'm trying to figure out who is right, and what is the right thing to do. Context: an intranet web application that our customers use for accounting ...
2
votes
2answers
2k views

Should I represent special cases (like errors / exceptions) in UML diagrams?

Let's say you write a program that, when started, reads its configuration file to know which modules to start-up etc. If that configuration file is missing, an error will probably show up. This is an ...
82
votes
12answers
7k views

How big does my project need to be for me to unit test it? [closed]

I assume that my project is decoupled enough to allow for unit testing. But how big, exactly, in terms of clases and functions does my project need to be to make unit testing worthwhile? We all make ...
0
votes
1answer
1k views

Generic way of handling exceptions in windows phone? [closed]

I mean what are some of the ways other programmers deal with exception for example, when an error occurs when accessing a web service for say. If an example cant be given for windows phone, give the ...
1
vote
1answer
112 views

How I identify true error?

I am writing a program to scrap some data from the web. The pages are sequential ( 1,2,3 ... ), but I have no idea when will it stops. I combine a prefix and a integer to make a link for the python ...
2
votes
1answer
3k views

web server response code 500

I realize that this may spur a religious discussion, but I discussed this with friends and get great, but conflicting answers and the actual documentation is of little help. What does the 500 series ...
2
votes
3answers
1k views

Good practice or service for monitoring unhandled application errors for a small organization

I'm working with multiple software with varying ways of monitoring for errors. When I make software, I usually send email with the stack trace to admins(usually me). Some customer software is ...
14
votes
5answers
6k views

null pointers vs. Null Object Pattern

Attribution: This grew out of a related P.SE question My background is in C / C++, but I have worked a fair amount in Java and am currently coding C#. Because of my C background, checking passed and ...
76
votes
16answers
16k views

Should one check for null if he does not expect null?

Last week, we had a heated argument about handling nulls in our application's service layer. The question is in the .NET context, but it will be the same in Java and many other technologies. The ...
91
votes
11answers
14k views

The modern way to perform error handling…

I've been pondering this problem for a while now and find myself continually finding caveats and contradictions, so I'm hoping someone can produce a conclusion to the following: Favour exceptions ...
24
votes
5answers
28k views

try-catch in javascript… isn't it a good practice?

There is a provision for try-catch block in javascript. While in java or any other language it is mandatory to have error handling, I don't see anybody using them in javascript for greater extent. ...
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votes
3answers
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Different callbacks for error or error as first argument?

We (and the JS SO chat room) had a talk with @rlemon some days ago about his Little-XHR library about error handling. Basically, we wanted to decide which error handling pattern should be used: ...