Make sure nothing is nil in tmp slice

[thor-son]

Annotation is writed Make sure nothing is nil.
when dst slice cap is bigger than len, some argsKV elements is nil.
So fill empty slice in for loop and Make sure nothing is nil.

[li-jin-gou]

Some code examples and descriptions can be added to help understand the role of PR

[thor-son]

use start index len(dst) for loop (current)

	tmp := make([]argsKV, 5)
	dst := make([]argsKV, 2)
	dst[0] = argsKV{key: []byte{'k'}, value: []byte{'0'}}
	dst[1] = argsKV{key: []byte{'k'}, value: []byte{'1'}}

	dst = append(dst, argsKV{key: []byte{'k'}, value: []byte{'2'}})
	//cap(dst) == 4, len(dst) == 3
	dst = dst[:cap(dst)]
	//cap(dst) == 4, len(dst) == 4
	copy(tmp, dst)

	for i := len(dst); i < len(tmp); i++ {
		// Make sure nothing is nil.
		tmp[i].key = []byte{}
		tmp[i].value = []byte{}
	}
	fmt.Println(tmp[3].key == nil) // true
	fmt.Println(tmp[4].key == nil) // false

use start index dstLen for loop (pr)

	tmp := make([]argsKV, 5)
	dst := make([]argsKV, 2)
	dst[0] = argsKV{key: []byte{'k'}, value: []byte{'0'}}
	dst[1] = argsKV{key: []byte{'k'}, value: []byte{'1'}}

	dst = append(dst, argsKV{key: []byte{'k'}, value: []byte{'2'}})
	//cap(dst) == 4, len(dst) == 3
	dstLen := len(dst)
	dst = dst[:cap(dst)]
	//cap(dst) == 4, len(dst) == 4
	copy(tmp, dst)

	for i := dstLen; i < len(tmp); i++ {
		// Make sure nothing is nil.
		tmp[i].key = []byte{}
		tmp[i].value = []byte{}
	}
	fmt.Println(tmp[3].key == nil) // false.  <-- Make sure nothing is nil.
	fmt.Println(tmp[4].key == nil) // false

[erikdubbelboer]

Thanks!