from https://www.kmwebdev.me/blog/night-of-the-living-bugs
At 4 AM, the CI pipeline wasn’t broken. It was confused. What I thought was a simple automated check had turned into a chain of small misunderstandings across multiple systems.
Everything was still “working,” but the results no longer made sense. That gap between execution and understanding is where everything started to fail.
The system I thought I was building
The goal was simple: run automated checks on a website, measure performance, and return a clear pass or fail result.
Check if the site loads correctly
Measure performance metrics
Validate stability
Return a single decision
On paper, it was deterministic. In reality, it depended on many components agreeing on how data should move between them.
The first sign of failure
The system didn’t crash. It returned incomplete results. Some values were missing. Others were undefined. The final output simply said: FAILED.
But it couldn’t clearly explain why.
It wasn’t broken. It was confused.
Where things started drifting
Each part of the system assumed the previous part had already done the necessary transformation. But those assumptions were never explicitly defined.
Small mismatches started accumulating:
One step expected structured data, another sent raw output
Some values were optional but treated as required
Undefined values propagated silently through the pipeline
Nothing failed loudly. Everything failed quietly while still running.
The environment failure
Once internal issues were reduced, a different problem appeared: the system tried to use a tool that wasn’t installed.
No crash. Just a message:
“I can’t find what I was told to use.”
At that point, it stopped being a logic problem and became a setup problem.
The turning point
The breakthrough wasn’t a fix. It was separation.
One stable version for known behavior
One experimental version for testing changes
Before this, everything was mixed together. Every change had unpredictable effects. After separation, the system finally became observable again.
What this actually was
This wasn’t a single bug. It was multiple small gaps aligning at once.
Data contract mismatches between layers
Missing environment dependencies
Unstable state across versions
Over-composition before stabilization
Most systems don’t fail dramatically. They fail quietly while still running.
Closing thought
I thought I was debugging a CI pipeline. But I was really debugging assumptions: the invisible agreements between parts of a system.
The bugs weren’t random. They were the system failing to agree with itself.
Top comments (0)