new vs make

Canonical guidance

• use make for slices, maps, and channels
• use new rarely, when a pointer to a zero value is specifically what you want
• prefer composite literals when they read more clearly

Use when

• creating maps or channels
• deciding between pointer allocation styles
• explaining nil versus ready-to-use values

Avoid

• new(map[string]int)
• new([]byte) when a literal or make is intended
• treating new and make as interchangeable

Preferred pattern

m := make(map[string]int)

Anti-pattern

• allocating with new and then wondering why the map or channel is still unusable

Explanation: This is tempting because both forms allocate something, but they produce different kinds of results with different readiness semantics.

Why

• many early Go bugs are really about misunderstanding what was initialized