json: use reflect.IsZero on arrays instead of len check

Author: as

encode_patch_test.go

@@ -0,0 +1,27 @@
+package json
+
+import (
+	"testing"
+	"time"
+)
+
+func TestMarshalPatch(t *testing.T) {
+	type S struct{
+		T int
+		U string
+	}
+	v := struct {
+		A [2]float64
+		B time.Time
+		C S
+
+		X [2]float64 `json:",omitempty"`
+		Y time.Time `json:",omitempty"`
+		Z S `json:",omitempty"`
+	}{}
+	want := `{"A":[0,0],"B":"0001-01-01T00:00:00Z","C":{"T":0,"U":""}}`
+	have, _ := Marshal(v)
+	if h, w := string(have), want; h != w {
+		t.Fatalf("have %s, want %s", h, w)
+	}
+}