Skip to main content

Pragmatic developers guide to river crossing

TODOs, FIXMEs, issue links, and hacks are terms in a codebase that get the blood boiling for some, but I am almost always glad when I see them nowadays. The terms have saved me from ghost chases more times than I want to know. My thoughts on the matter are best explained by this little tale.

Let's imagine a dev team tasked with figuring out a way to transport a wolf, goat, and cabbage across a river. They have been contracted by a client expert in transport systems

After a discussion with the domain specialists, the developers conclude that renting a boat for the river crossing is the way to go since it is the most cost-effective. 

The transportation design is abstracted with an open-source library. Perfect! Such an easy job, right? Provided, of course, that the library API is decent.

It turns out the library, although simple, could be better. It is imperative, stateful, and cumbersome—very outdated stuff. There are fortunately, only three public functions, init, load and moveToNextBank. The library needs to be initialized with the transported items while load takes an index of an element in said item array. One transported thing at a time, weird!

They start with this code.

But when they run the program, they get an index out-of-bounds error. The baffled developers tear their hair and try to figure out what is happening.

After some trial and error, they realize that the payload array loses the last index if the wolf is moved first. Bizarrely, they notice that if they carry the cabbage first, the middle index (goat) disappears from the boat state. 

After hours and hours of brute force hacking, they figure out a bunch of edge cases that corrupt the library's initial state. Working around the bugs, they write the following code successfully transporting the payload.

Job done! They check the code and move to the next assignment.

🤔

We can do better! Let's rewind to the beginning.

In an alternate timeline, as the team taking the task notices the library quirks, they search the internet for alternatives to the transport library and unfortunately discover none. Accepting the fact and given the time pressure, they reluctantly stick to it.

When they run into bugs in the library, they write issues and pull requests to the open-source repository. Their code ends up like this.

The team understands the code could be better and could also isolate the unclean API in the codebase, but since they contributed to upstream, they decided to live with the clutter until it is released. They also write a unit test that fails if the library is updated, enforcing a rewrite.

Once you work with something confusing, clarify in your code (not just in the issue tracker) why it is illogical and why. Of course, in the ideal world, one creates abstractions that make it simpler but sometimes, it is just not possible or feasible.


They also could have just asked OpenAI!

Comments

Popular posts from this blog

I'm not a passionate developer

A family friend of mine is an airlane pilot. A dream job for most, right? As a child, I certainly thought so. Now that I can have grown-up talks with him, I have discovered a more accurate description of his profession. He says that the truth about the job is that it is boring. To me, that is not that surprising. Airplanes are cool and all, but when you are in the middle of the Atlantic sitting next to the colleague you have been talking to past five years, how stimulating can that be? When he says the job is boring, it is not a bad kind of boring. It is a very specific boring. The "boring" you would want as a passenger. Uneventful.  Yet, he loves his job. According to him, an experienced pilot is most pleased when each and every tiny thing in the flight plan - goes according to plan. Passengers in the cabin of an expert pilot sit in the comfort of not even noticing who is flying. As someone employed in a field where being boring is not exactly in high demand, this sounds pro...

Canyon Precede:ON 7

I bought or technically leased a Canyon Precede:ON 7 (2022) electric bike last fall. This post is about my experiences with it after riding for about 2000 km this winter. The season was a bit colder than usual, and we had more snow than in years, so I properly put the bike through its paces. I've been cycling for almost 20 years. I've never owned a car nor used public transport regularly. I pedal all distances below 30km in all seasons. Besides commuting, I've mountain biked and raced BMX, and I still actively ride my road bike during the spring and summer months. I've owned a handful of bikes and kept them until their frames failed. Buying new bikes or gear has not been a major part of my hobby, and frankly, I'm quite sceptical about the benefits of updating bikes or gear frequently. I've never owned an E-bike before, but I've rented one a couple of times. The bike arrived in a hilariously large box. I suppose there's no need to worry about damage durin...

Extracting object properties from an IFC file with IfcOpenShell

Besides the object geometry information, IFC files may contain properties for the IFC objects. The properties can be, for example, some predefined dimension information such as an object volume or a choice of material. Some of the properties are predefined in the IFC standards, but custom ones can be added. IFC files can be massive and resource-intensive to process, so in some cases, it helps to separate the object properties from the geometry data. IfcOpenShell  is a toolset for processing IFC files. It is written mostly in C++ but also provides a Python interface. To read an IFC file >>> ifc_file = ifcopenshell.open("model.ifc") Fetch all objects of type IfcSlab >>> slab = ifc_file.by_type("IfcSlab")[1] Get the list of properties >>> slab.IsDefinedBy (#145075=IfcRelDefinesByType('2_fok0__fAcBZmMlQcYwie',#1,$,$,(#27,#59),#145074), #145140=IfcRelDefinesByProperties('3U2LyORgXC2f_hWf6I16C1',#1,$,$,(#27,#59),#145141), #145142...