Go Interface Conversion Panic (interface is X, Not Y)
An interface conversion panic means a type assertion assumed an interface value held a specific concrete type, but at runtime it actually held a different one...
Category
Go / Gin
Debugging Go services and the Gin web framework.
Gin Binding JSON Returns Empty Struct
When Gin's JSON binding produces a struct with all fields at their zero values, despite the request clearly containing valid JSON, it's almost always due to a...
Gin Middleware Not Running in Expected Order
Gin middleware runs in the order it's registered, and confusion about execution order almost always comes down to either registration happening in a different...
Go Goroutine Leak, How to Detect and Fix
A goroutine leak happens when a goroutine gets stuck permanently — usually blocked waiting on a channel operation that will never complete — and never...
Go "Nil Pointer Dereference" Panic, How to Debug
A nil pointer dereference panic means your code tried to access a field or method on a pointer that was never actually assigned a valid value — Go's type...
Go "Undefined: Package" After Adding New File
When Go reports something as "undefined" right after you add a new file to an existing package, the new file's contents almost always aren't actually part of...
Gin CORS Error Blocking React Native Requests
A CORS error between a React Native app and a Gin backend is technically a browser-enforced restriction, but it commonly shows up during development with tools...
Gin Router Returning 404 on Valid Route
When a Gin route returns a 404 even though the handler is clearly registered and the path looks correct, the cause is almost always a subtle mismatch between...
Go GORM Foreign Key Constraint Violation on Insert
A foreign key constraint violation in GORM during an insert almost always means you're trying to save a record that references a parent row which doesn't exist...