Recent Articles

Mar 2025

The Rounding Error

by in Representative Line on

At one point, someone noticed that some financial transactions weren't summing up correctly in the C# application Nancy supported. It didn't require Superman or a Peter Gibbons to figure out why: someone was using floating points for handling dollar amounts.

That kicked off a big refactoring project to replace the usage of double types with decimal types. Everything seemed to go well, at least until there was a network hiccup and the application couldn't connect to the database. Let's see if you can figure out what happened:

14 comments - Last comment @ 18:28

NaN is the Loneliest Number

by in Error'd on

Today we have a whole batch of category errors, picked out from the rash of submissions and a few that have been festering on the shelf. Just for fun, I threw in an ironic off-by-some meta-error. See if you can spot it.

Adam R. "I'm looking for hotel rooms for the 2026 Winter Olympics in Milan-Cortina. Most hotels haven't opened up reservations yet, except for ridiculously overprice hospitality packages. This search query found NaN facilities available, which equates to one very expensive apartment. I guess one is not a number now?"

8 comments - Last comment @ 13:12

Over Extended Methods

by in Feature Articles on

Jenny had been perfectly happy working on a series of projects for her company, before someone said, "Hey, we need you to build a desktop GUI for an existing API."

The request wasn't the problem, per se. The API, on the other hand, absolutely was.

17 comments - Last comment @ 2025-03-20

Reliability Test

by in CodeSOD on

Once upon a time, Ryan's company didn't use a modern logging framework to alert admins when services failed. No, they used everyone's favorite communications format, circa 2005: email. Can't reach the database? Send an email. Unhandled exception? Send an email. Handled exception? Better send an email, just in case. Sometimes they go to admins, sometimes they just go to an inbox used for logging.

Let's look at how that worked.

19 comments - Last comment @ 2025-03-23

Spaced Out Prefix

by in CodeSOD on

Alex had the misfortune to work on the kind of application which has forms with gigantic piles of fields, stuffed haphazardly into objects. A single form could easily have fifty or sixty fields for the user to interact with.

That leads to C# code like this:

15 comments - Last comment @ 2025-03-19

Too Many Red Flags

by in Feature Articles on

Fresh out of university, Remco accepted a job that allowed him to relocate to a different country. While entering the workforce for the first time, he was also adjusting to a new home and culture, which is probably why the red flags didn't look quite so red.

The trouble had actually begun during his interview. While being questioned about his own abilities, Remco learned about Conglomcorp's healthy financial position, backed by a large list of clients. Everything seemed perfect, but Remco had a bad gut feeling he could neither explain nor shake off. Being young and desperate for a job, he ignored his misgivings and accepted the position. He hadn't yet learned how scarily accurate intuition often proves to be.

22 comments - Last comment @ 14:25

No Time Like the Present

by in Error'd on

I'm not entirely sure I understand the first item today, but maybe you can help. I pulled a couple of older items from the backlog to round out this timely theme.

Rudi A. reported this Errord, chortling "Time flies when you're having fun, but it goes back when you're walking along the IJ river!" Is the point here that the walking time is quoted as 77 minutes total, but the overall travel time is less than that? I must say I don't recommend swimming the Ij in March, Rudi.

15 comments - Last comment @ 2025-03-17

Don't Date Me

by in CodeSOD on

I remember in some intro-level compsci class learning that credit card numbers were checksummed, and writing basic functions to validate those checksums as an exercize. I was young and was still using my "starter" credit card with a whopping limit of $500, so that was all news to me.

Alex's company had a problem processing credit cards: they rejected a lot of credit cards as being invalid. The checksum code seemed to be working fine, so what could the problem be? Well, the problem became more obvious when someone's card worked one day, and stopped working the very next day, and they just so happened to be the first and last day of the month.

14 comments - Last comment @ 2025-03-19

Expressing a Leak

by in CodeSOD on

We previously discussed some whitespacing choices in a C++ codebase. Tim promised that there were more WTFs lurking in there, and has delivered one.

Let's start with this class constructor:

20 comments - Last comment @ 2025-03-13

Broken Up With

by in Representative Line on

Marco found this wreck, left behind by a former co-worker:

$("#image_sample").html('<i><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />No image selected, select an image to see how it looks in the banner!</i>');
28 comments - Last comment @ 10:29

Where is the Validation At?

by in CodeSOD on

As oft stated, the "right" way to validate emails is to do a bare minimum sanity check on format, and then send a verification message to the email address the user supplied; it's the only way to ensure that what they gave you isn't just syntactically valid, but is actually usable.

But even that simple approach leaves places to go wrong. Take a look at this code, from Lana.

15 comments - Last comment @ 2025-03-11

Tomorrow

by in Error'd on

It's only a day away!

Punctual Robert F. never procrastinates. But I think now would be a good time for a change. He worries that "I better do something quick, before my 31,295 year deadline arrives."

5 comments - Last comment @ 2025-03-07

An Argument With QA

by in CodeSOD on

Markus does QA, and this means writing automated tests which wrap around the code written by developers. Mostly this is a "black box" situation, where Markus doesn't look at the code, and instead goes by the interface and the requirements. Sometimes, though, he does look at the code, and wishes he hadn't.

Today's snippet comes from a program which is meant to generate PDF files and then, optionally, email them. There are a few methods we're going to look at, because they invested a surprising amount of code into doing this the wrong way.

9 comments - Last comment @ 2025-03-07

Wrap Up Your Date

by in CodeSOD on

Today, we look at a simple bit of bad code. The badness is not that they're using Oracle, though that's always bad. But it's how they're writing this PL/SQL stored function:

  FUNCTION CONVERT_STRING_TO_DATE --Public
    (p_date_string IN Varchar2,
       p_date_format IN Varchar2 DEFAULT c_date_format)
    Return Date

   AS

   BEGIN

    If p_date_string Is Null Then
        Return Null;
      Else
        Return To_Date(p_date_string, p_date_format);
      End If;

   END;  -- FUNCTION CONVERT_STRING_DATE
20 comments - Last comment @ 2025-03-07

The Sales Target

by in Feature Articles on

The end of the quarter was approaching, and dark clouds were gathering in the C-suite. While they were trying to be tight lipped about it, the scuttlebutt was flowing freely. Initech had missed major sales targets, and not just by a few percentage points, but by an order of magnitude.

Heads were going to roll.

16 comments - Last comment @ 2025-03-07

An Alerting Validation

by in CodeSOD on

There are things which are true. Regular expressions frequently perform badly. They're hard to read. Email addresses are not actually regular languages, and thus can't truly be validated (in all their many possible forms) by a pure regex.

These are true. It's also true that a simple regex can get you most of the way there.

26 comments - Last comment @ 2025-03-11
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