Printing a slice at non-0 base shows wrong "more"

[Tim Hockin]

(dlv) call len(c.variables)
> k8s.io/kubernetes/test/instrumentation.(*metricDecoder).decodeString() ./test/instrumentation/decode_metric.go:201 (PC: 0xaab677)
Values returned:
	: 29

(dlv) p c.variables[28:]
map[string]go/ast.Expr [
	"compbasemetrics.processStartTime": *go/ast.CallExpr {
		Fun: go/ast.Expr(*go/ast.Ident) *{
			NamePos: 651,
			Name: "NewGaugeVec",
			Obj: *go/ast.Object nil,},
		Lparen: 662,
		Args: []go/ast.Expr len: 2, cap: 2, [
			...,
			...,
		],
		Ellipsis: NoPos (0),
		Rparen: 843,}, 
	...+28 more
]

Note the "+28 more".

Delve Debugger
Version: 1.22.0
Build: $Id: 61ecdbbe1b574f0dd7d7bad8b6a5d564cce981e9 $

go version go1.22.0 linux/amd64

[Alessandro Arzilli]

You mean 'map' not 'slice' right?

[Tim Hockin]

Oh. Interesting point. Why did it let me do slice indexing? Is that new? Is it sorted, and if so by what?

(dlv) l
> main.main() ./file.go:11 (PC: 0x4960ba)
     1:	package main
     2:	
     3:	import "fmt"
     4:	
     5:	func main() {
     6:	... s := []string{"zero", "one", "two", "three", "four", "five"}
     7:	... m := map[string]int{
     8:	... ... "zero": 100, "one": 101, "two": 102,
     9:	... ... "three": 103, "four": 104, "five": 105,
    10:	... }
=>  11:	... fmt.Println(s, m)
    12:	}
(dlv) p s[4:]
[]string len: 2, cap: 2, ["four","five"]
(dlv) p m[4:]
map[string]int [
	"four": 104, 
	"five": 105, 
	...+4 more
]

It appears to be sorted in insert order - is that a quarantee?

[Alessandro Arzilli]

Why did it let me do slice indexing? Is that new?

Incremental load, it's been there for years.

Is it sorted, and if so by what? It appears to be sorted in insert order - is that a quarantee?

The order is an implementation detail: it's the order you will get from for range minus the starting point randomization.

[Tim Hockin]

Cool! I did not know this worked. Thanks.