Fix combination generator in CompoundMultiIndex

.circleci/config.yml

@@ -2,7 +2,7 @@ version: 2.1
 
 references:
   images:
-    go: &GOLANG_IMAGE docker.mirror.hashicorp.services/circleci/golang:1.15.3
+    go: &GOLANG_IMAGE docker.mirror.hashicorp.services/circleci/golang:1.16.7
 
 # reusable 'executor' object for jobs
 executors:

index.go

@@ -821,7 +821,9 @@ forloop:
 		if depth == len(builder)-1 {
 			// These are the "leaves", so append directly
 			for _, v := range builder[depth] {
-				out = append(out, append(currPrefix, v...))
+				outcome := make([]byte, len(currPrefix))
+				copy(outcome, currPrefix)
+				out = append(out, append(outcome, v...))
 			}
 			return
 		}

index_test.go

@@ -5,6 +5,7 @@ import (
 	crand "crypto/rand"
 	"encoding/binary"
 	"fmt"
+	"reflect"
 	"sort"
 	"strings"
 	"testing"
@@ -1314,3 +1315,44 @@ func TestCompoundIndex_PrefixFromArgs(t *testing.T) {
 		t.Fatalf("expected an error when passing too many arguments")
 	}
 }
+
+func TestCompoundMultiIndex_FromObject(t *testing.T) {
+	// handle sub-indexer case unique to MultiIndexer
+	obj := &TestObject{
+		ID:       "obj1-uuid",
+		Foo:      "Foo1",
+		Baz:      "yep",
+		Qux:      []string{"Test", "Test2"},
+		QuxEmpty: []string{"Qux", "Qux2"},
+	}
+	indexer := &CompoundMultiIndex{
+		Indexes: []Indexer{
+			&StringFieldIndex{Field: "Foo"},
+			&StringSliceFieldIndex{Field: "Qux"},
+			&StringSliceFieldIndex{Field: "QuxEmpty"},
+		},
+	}
+
+	ok, vals, err := indexer.FromObject(obj)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if !ok {
+		t.Fatalf("should be ok")
+	}
+	// this goes in between each index prefix to compare them correctly
+	nilb := string([]byte{0})
+	want := []string{
+		"Foo1" + nilb + "Test" + nilb + "Qux" + nilb,
+		"Foo1" + nilb + "Test" + nilb + "Qux2" + nilb,
+		"Foo1" + nilb + "Test2" + nilb + "Qux" + nilb,
+		"Foo1" + nilb + "Test2" + nilb + "Qux2" + nilb,
+	}
+	got := make([]string, len(vals))
+	for i, v := range vals {
+		got[i] = string(v)
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("\ngot:  %+v\nwant: %+v\n", got, want)
+	}
+}