net/http: Header.Clone behavior

[dsnet]

The Header.Clone method is being added in Go1.13. It's current behavior is to always allocate a map and return it even if the receiver is nil.

Thus:

h1 := http.Header(nil)
h2 := h1.Clone()
fmt.Println(h1 == nil) // true
fmt.Println(h2 == nil) // false

Is this behavior we want to go with? It seems more consistent for Clone to return nil if the receiver is also nil.

[andybons]

Agree. Will send a change.

@bsiegert

[gopherbot]

Change https://golang.org/cl/188022 mentions this issue: net/http: return nil from Header.Clone if the receiver is nil

[odeke-em]

Good catch @dsnet! I agree that passing a nil header to Clone should also return a nil header and I'll review @andybons' CL