Krzysztof Kowalczyk • 7/6/2025

Explaining nil interface{} gotcha in Go

This technical article delves into a common 'gotcha' in Go programming: why a nil pointer of a specific type (e.g., *Foo) assigned to an empty interface (interface{}) does not compare as equal to nil. It explains that an interface value is a (type, value) pair, where nil is (no type, no value), and a nil pointer is (concrete type, nil). The post includes code examples and discusses using reflection to properly check for nil pointers within interfaces.

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#pointers #interface #reflection