Debugging is the process of examining the state of a program - generally with a debugging tool - while it is running and attempting to find bugs that cause it to behave abnormally.

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Never written much unit tests, how can I practice more of it?

I have an interview coming up soon next week and there's a few things on their list of responsibilties for this software development job (the job position title is vague, it says java developer) that ...
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2answers
433 views

Is it possible to prune the stacktrace returned for a custom exception in PHP

I am working on a project in PHP that does a lot of input validation and can throw different custom exception classes in various layers of the application. To make the project code easier to read, ...
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Debug multiprocessing in Python

What are some good practices in debugging multiprocessing programs in Python?
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2answers
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How do you find errors related to undeclared variables in php?

If I copy a piece of code from somewhere that looks like so $blah = array(1,2,3,4); foreach ($blah as $i) echo ($i); and rename the variables but forget to do it correctly like so $apple = ...
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5answers
2k views

What is a practical way to debug Rails?

I get the impression that in practice, debuggers are rarely used for Rails applications. (Likewise for other Ruby apps, as well as Python.) We can compare this to the usual practice for Java or ...
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6answers
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What's a good approach to adding debug code to your application when you want more info about what's going wrong?

When our application doesn't work the way we expect it to (e.g. throws exceptions etc.), I usually insert a lot of debug code at certain points in the application in order to get a better overview of ...
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1answer
151 views

Is it okay to call exception-triggered debugging “post-mortem debugging”?

I heard the term "post-mortem debugging", and Wikipedia says it's debugging done after the program has crashed. I often debug Python apps using a debugger that stops execution once an ...
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10answers
1k views

Why not use the word bug instead of exception? [closed]

If we refer to exceptions as bugs, why not just call it a bug in the first place instead of an exception? If in the code it's called exception and as soon as it occurs it's called a bug. Then why not ...
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16answers
2k views

How to spend less time on debugging? [closed]

Following the Pareto rule, a programmer spends only 20% of his time for really useful things. I spend 80% of my time debugging, fixing small things to get everything working. Is there a way to spend ...
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4answers
244 views

Pesky bugs - nonexistant?

Very short introduction (this is quite a context-heavy question): I'm a 17 year old script kiddo/programmer, doing some projects, usually netting around 20 files of 200 lines each. I usually don't ...
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13answers
1k views

Can we guarantee a program will never go wrong?

We have a system here. Recently there is a wrong calculation in one of the number in the report generated by the system. Through out our experience, we've never encounter any problem/error in this ...
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5answers
227 views

Value of maintaining debug outputs

A developer on our team litters his code with debug outputs. He passes many parameters into methods that are only used for debugging. Personally I find this clutters up the code. If I need to debug ...
5
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2answers
188 views

Are there decent entry-level tutorials on debugging? [closed]

In the tags I frequent on Stack Overflow, a big chunk of questions should be answered with some basic knowledge about how to debug things - ie., teaching the OP to fish - instead of giving a fix for ...
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4answers
460 views

Have you ever found a bug you can't solve? What do you do in that case?

We're developing a hosted CMS, something like WordPress.com. When we were creating the Image Gallery module, we examined many jQuery libraries like easySlider, jCarousel, and Nivo Slider. But each of ...
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20answers
2k views

How do you tackle really bizarre errors that keep you puzzled for more than 10 hours? [closed]

You know them, those errors that make NO sense. Where it seems like a gremlin just jumped deep inside your chips and messed up something. Do you take a walk, write stuff, call an uncle?
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5answers
287 views

Where to start fixing a complex bug?

I'm trying to solve a complex bug in our codebase , but the problem seems to be coming from a lot of places to the point that i dont know what to change first . do you have any procedure or ...
55
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21answers
6k views

“It was working yesterday, I swear!” What can you do? [closed]

When you arrive in the morning, you find that your software does not work anymore, even though it did when you left yesterday evening. What do you do? What do you check first? What do you do to stop ...
6
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3answers
260 views

Multitasking how to keep track of what you're doing

I'm in a long debugging task, I need to figure out where to hook up some extra functionality I need. It's cumbersome work, and I've been debugging 2 whole days, and I'm on my third, but I work in ...
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3answers
198 views

Supplying code to people helping you debug?

I was wondering if it is wise or advisable to send over a large amount of source code of one's application for debugging and error solving purposes, I'm working on an iOS app that I hope to release to ...
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4answers
854 views

How do I isolate difficult to reproduce bugs?

There's a bug in my program. Doesn't really matter what the platform is. Every so often, a row in a ListView is the wrong color. I tried setting a watchpoint for the variable that is supposed to ...
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5answers
1k views

Using A Debugger (An Interview Question)

During a phone interview I had, the interviewer was asking me questions about my previous job as a web developer. After discussing how I had used Eclipse to write Java Servlets, he asked me the ...
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5answers
401 views

Invert how to teach programming?

I was thinking about the responses to my thread on programming Program like a writer..? and most people agreed that you should have some structure and build from there instead of just typing away. New ...
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2answers
305 views

Terminology question: Generalize Heisenbug

Is there some kind of generalization to the effect called Heisenbug? Because I would like to describe in my documentation how instrumenting a program changes the execution no matter what. In The New ...
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3answers
841 views

Debugging Facts and Statistics [closed]

I'm trying to find a research answering a question: "How much time developers spend on development vs debugging?". I found several interesting links on the Net but they are little too old. This 2002 ...
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4answers
1k views

how to start fixing bugs in open source softwares

I a student and have good knowledge in C programming and like to contribute any open source project which is developed in C. I searched sourceforge and selected 7-Zip because its widely used one and ...
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2answers
207 views

Fixing sudden serious problem in software

For example, company that uses our software suddenly has found a serious bug and can't continue to work. The bug has exposed a big problem in software design and fixing it will take few days. What is ...
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5answers
1k views

Is possible to write too many asserts?

I am a big fan of writing assert checks in C++ code as a way to catch cases during development that cannot possibly happen but do happen because of logic bugs in my program. This is a good practice in ...
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13answers
778 views

Logging, do you do it? [closed]

Back on my theme of late: interview questions. Was recently asked to describe a time I'd used logging. My first instinct was to respond with compiler warnings set to full and error-out. What he was ...
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7answers
523 views

Why don't schools cover debuggers?

After yet another homework question on SO. It seems like that vast majority of students have no idea what a debugger is or how to use one. I feel that knowing how to use a debugger is almost as ...
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10answers
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What is the difference between debugging and testing?

Introduction To Software Testing (Ammann & Offutt) mentions on p.32 a 5-level testing maturity model: Level 0 There’s no difference between testing and debugging. Level 1 The purpose of testing ...
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9answers
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What to do when you have exhausted all avenues to fix a bug

I am a Junior Programmer(4 months career experience so far) working on a Cross Platform Mobile Application (1 person team - so its just myself). I have a bug in this program/app which is pretty large ...
12
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15answers
5k views

Real programmers use debuggers? [closed]

If experienced programmers actually ever use debuggers, and if so under what circumstances. Although in the answer to that question I said "months" ago I probably meant "years" - I really don't use a ...
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3answers
350 views

Un-Explainable Bugs?

I've encountered bugs that are extremely difficult to reproduce reliably and/or explain definitively, but that appear to be solved. When this happens, how much time should I spend chasing it down? ...
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11answers
578 views

How to teach your users/customers to send better error descriptions

I often have to deal with customers or users which are reporting errors in applications. Most of the time their content is something useless as ERROR!!! x does not work without much more ...
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3answers
158 views

How to Identify Bugs

Sometimes I come across something that doesn't entirely work right or just doesn't make sense to me and I often refrain from thinking it is a bug in the library or code I am using. For instance ...
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5answers
402 views

Should I release source code to fix bug

I have a bug in my application that I'm building. I asked a question on S.O. and one of the users asked me to post or send all the code to him so he could look at it. I totally understand the ...
9
votes
11answers
1k views

Turn away a bug if no reproducible test case exists? [duplicate]

If the customer has problems which are not reproducible because of complexity of actions they took and can't remember step by step, then coders are missing a test case. Indeed, this issue is ...
11
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13answers
964 views

What is the biggest trouble developers encounter when debugging?

I just wonder what is the biggest trouble developers encounter when debugging? I can think of three answers but I am not sure whether they are correct: Trouble in locating the bug? But most of the ...
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2answers
234 views

Open Source: Is Testing/Bug Reporting A Major Contribution?

When evaluating contributions to open source projects, does testing the code on various real-world inputs, reducing a large number of complicated bugs to small test cases and filing good bug reports ...
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2answers
844 views

What's better than outputdebugstring for windows debugging?

So, before I came to my current place of employment, the windows OutputDebugString function was completely unheard of, everyone was adding debug messages to string lists and saving them to file or ...
14
votes
11answers
743 views

Is fixing bugs made by other people a good approach?

Let's assume the situation where a team of four developers is building an application. During the testing phase, bugs are reported by users. Who should fix them? The person who committed the erroneous ...
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9answers
910 views

How to effectively do manual debugging? [closed]

Say you don't have a debugger available, what would be an effective approach to debug code which doesn't work (as expected)?
5
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1answer
120 views

Is there any plugin for better viewing of exceptions?

I don’t think that I’m the only one that thinks that Visual Studio exception window is very poor. Trace information lacking formatting and is hardly readable. Is there any plugin or external tool ...
4
votes
1answer
393 views

What are some good resources for debugging/disassembling proprietary software? [closed]

From time to time, I experience different bugs with proprietary software that I need to interact with. In order to get through these bugs, I need to develop various workarounds. Is there a good book ...
10
votes
7answers
273 views

What approaches can I take to lower the odds of introducing new bugs in a complex legacy app?

Where I work I often have to develop (and bug fix) in an old system (.NET 1) whos code is complete spaghetti - with little thought given to variable names, program structure nor comments. Because of ...
10
votes
1answer
21k views

How can I debug a JSP?

I'm trying to edit a JSP for a project and I'm getting a NullPointerException somewhere in the JSP when it's requested from my server. My web server (JBoss) is reporting the exception, but it's ...
12
votes
6answers
3k views

What do you look for when debugging deadlocks?

Recently I've been working on projects that heavily use threading. I think that I'm OK at designing them; use stateless design as much as possible, lock access to all resources that more than one ...
14
votes
8answers
1k views

What process do you normally use when attempting to debug a problem/issue/bug with your software? [closed]

Most people seem to treat debugging as an art, rather than a science. For those here which treat it as a science, rather than an art - what process(es) do you normally use when faced with a new ...
4
votes
4answers
112 views

What features are helpful when performing remote debugging / diagnostics?

Obviously, the easiest way to solve a bug is to be able to reproduce it in-house. However, sometimes that is not practical. For starters, users are often not very good at providing you with useful ...
7
votes
11answers
438 views

How to program something with the expectation that it will work the first time?

I had a friend in college who programmed something that worked the first time, that was pretty amazing. But as for me, I just fire up the debugger as soon as I finally get whatever I'm working on to ...