Golang Pitfalls: Functions & Methods

Source material: mistakes #42-47 from 100 Go Mistakes and How to Avoid Them (teivah/100-go-mistakes).

Apply these rules when designing Go functions and methods.

42. Not knowing which receiver to use (#42)

Receiver must be a pointer:

• If the method mutates the receiver (including appending to a slice receiver: func (s *slice) add(el int)).
• If the receiver contains a field that cannot be copied (e.g., a sync type — see #74).

Receiver should be a pointer:

• If the receiver is a large object (avoids expensive copies; benchmark when unsure).

Receiver must be a value: