Merge slice with override no effect

[wen-bing]

package test5

import (
	"testing"

	"github.com/imdario/mergo"
)

type Strudent struct {
	Name  string
	Books []string
}

func TestSliceNotOverride(t *testing.T) {
	var s1 = Strudent{
		Name:  "Jack",
		Books: []string{"a", "B"},
	}

	var s2 = Strudent{
		Name:  "Tom",
		Books: []string{"1"},
	}

	err := mergo.Merge(&s2, s1, mergo.WithOverride)
	if err != nil {
		t.Log("merge error")
		t.Fail()
	}
	if len(s2.Books) != 2 {
		t.Log("slice not ovrride")
		t.Fail()
	}
}

I expect s2's Books are overrided by s1's Books, however the test failed.

[ravern]

I think the slice is appended.

[darccio]

@wen-bing, I checked your code and I confirm that the slice is being appended as @ravernkoh pointed. I think can be a bug but I need to check all the issues to see if it was reported before.

[darccio]

Ok, after reviewing other issues, Mergo works as intended. Merge will append to slices as it adds missing keys in maps. But you are right. WithOverride should work different, as it shouldn't append to destination slice.

[darccio]

It has been solved thanks to PR #70.

[darccio]

And it has been released as v0.3.3.

[wen-bing]

Awesome, Thanks!