strings: Join drops trailing empty strings

[jsumners]

Go version

1.22

Output of go env in your module/workspace:

Whatever go.dev/play has.

What did you do?

https://go.dev/play/p/lRtKx16rXk1

package main

import (
	"fmt"
	"strings"
)

func main() {
	lines := []string{
		"line 1",
		"",
		"line 2",
		"",
		"line 3",
		"",
	}

	joined := strings.Join(lines[0:4], "\n")

	foundCount := 0
	for _, c := range joined {
		if c == 0x0a {
			foundCount += 1
		}
	}

	fmt.Printf("found %d line feeds, expected 4", foundCount)
}

What did you see happen?

strings.Join skipped adding the intended final joining character.

What did you expect to see?

strings.Join would join all elements passed to it with the provided joining character.

[fzipp]

strings.Join skipped adding the intended final joining character.

You're cutting off the last two elements yourself: lines[0:4]

[jsumners]

The result should be line 1\n\nline 2\n\n.

[randall77]

A strings.Join of 4 items should have 3 separators, not 4.