This seems to be the hardest part with migration tools.
The more they try to be "universal" (compatible with different providers, protocols, and configurations), the more edge cases they have to handle, and that's where problems usually arise. Having a clear scope and an explicit indication of "this won't work here" is often more helpful than trying to support everything.
These incidents are a perfect example of how misleading "simple" systems can be.
From the outside, it looks like "just a cache misconfiguration," but in reality, the problem is more insidious because it's distributed across multiple layers:
- application logic (authentication limitations)
- CDN behavior -> infrastructure
- default settings that users rely on (no cache headers because the CDN was disabled)
The hardest part of debugging these cases isn't identifying what happened, but realizing where the model is flawed:
everything appears correct locally, the logs don't report any issues, yet users see completely different data.
I've seen similar cases where developers spent hours debugging the application layer before even considering that something upstream was silently changing the behavior.
These are the kind of incidents where the debugging path is anything but linear.
With legacy systems, at least the complexity was somewhat anticipated early in the design process (even if it was incorrect).
With automatically generated code, you get something that "works" but with a much vaguer underlying model, which makes it harder to understand when things start to go wrong.
In both cases, the real cost comes later, when you're forced to debug under pressure.
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