encoding/gob: cannot decode large []string

[RandomSort]

What version of Go are you using (go version)?

$ go version

1.20.2

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOOS="linux"

What did you do?

If you try to decode a []string larger than 655360 using encoding/gob, you get a panic as the slice helpers introduced in 1.20 did not extend the stringslice helper.

https://go.dev/play/p/Xe0ajfykrSm?v=goprev (thanks to Jacob Oaks)

What did you expect to see?

Successful decoding (https://go.dev/play/p/Xe0ajfykrSm?v=goprev ) <- 1.19

What did you see instead?

Panic (https://go.dev/play/p/Xe0ajfykrSm) <- 1.20

[gopherbot]

Change https://go.dev/cl/478215 mentions this issue: encoding/gob: Extend partially allocated string slices

[heschi]

cc @robpike

[ianlancetaylor]

FYI this was a mistake on my part, in CL 443777, and there is already an approved CL to fix it.