fix: [maps.Flatten] better handle keys with delimiter character via escape sequence

maps/maps.go

@@ -11,6 +11,12 @@ import (
 	"github.com/mitchellh/copystructure"
 )
 
+const (
+	escapeChar  = "~"
+	tildeEscape = escapeChar + "0"
+	delimEscape = escapeChar + "1"
+)
+
 // Flatten takes a map[string]interface{} and traverses it and flattens
 // nested children into keys delimited by delim.
 //
@@ -33,6 +39,21 @@ func Flatten(m map[string]interface{}, keys []string, delim string) (map[string]
 	return out, keyMap
 }
 
+func escape(keyPairs []string, delim string) []string {
+	if delim == "" {
+		return keyPairs
+	}
+	var result []string
+	for _, kp := range keyPairs {
+		// first pass, escape all escape characters
+		out := strings.ReplaceAll(kp, escapeChar, tildeEscape)
+		// second pass, escape the delimiter
+		out = strings.Replace(out, delim, delimEscape, -1)
+		result = append(result, out)
+	}
+	return result
+}
+
 func flatten(m map[string]interface{}, keys []string, delim string, out map[string]interface{}, keyMap map[string][]string) {
 	for key, val := range m {
 		// Copy the incoming key paths into a fresh list
@@ -45,7 +66,7 @@ func flatten(m map[string]interface{}, keys []string, delim string, out map[stri
 		case map[string]interface{}:
 			// Empty map.
 			if len(cur) == 0 {
-				newKey := strings.Join(kp, delim)
+				newKey := strings.Join(escape(kp, delim), delim)
 				out[newKey] = val
 				keyMap[newKey] = kp
 				continue
@@ -54,13 +75,28 @@ func flatten(m map[string]interface{}, keys []string, delim string, out map[stri
 			// It's a nested map. Flatten it recursively.
 			flatten(cur, kp, delim, out, keyMap)
 		default:
-			newKey := strings.Join(kp, delim)
+			newKey := strings.Join(escape(kp, delim), delim)
 			out[newKey] = val
 			keyMap[newKey] = kp
 		}
 	}
 }
 
+func unescape(keyPairs []string, delim string) []string {
+	if delim == "" {
+		return keyPairs
+	}
+	var result []string
+	for _, kp := range keyPairs {
+		// first pass, unescape the delimiter
+		out := strings.Replace(kp, delimEscape, delim, -1)
+		// second pass, unescape all escape characters
+		out = strings.Replace(out, tildeEscape, escapeChar, -1)
+		result = append(result, out)
+	}
+	return result
+}
+
 // Unflatten takes a flattened key:value map (non-nested with delimited keys)
 // and returns a nested map where the keys are split into hierarchies by the given
 // delimiter. For instance, `parent.child.key: 1` to `{parent: {child: {key: 1}}}`
@@ -79,7 +115,7 @@ func Unflatten(m map[string]interface{}, delim string) map[string]interface{} {
 		)
 
 		if delim != "" {
-			keys = strings.Split(k, delim)
+			keys = unescape(strings.Split(k, delim), delim)
 		} else {
 			keys = []string{k}
 		}

providers/nats/nats_test.go

@@ -28,6 +28,9 @@ func TestNats(t *testing.T) {
 	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
 		Bucket: "test",
 	})
+	if err != nil {
+		t.Fatal(err)
+	}
 	_, err = kv.Put("some.test.color", []byte("blue"))
 	if err != nil {
 		t.Fatal(err)
@@ -46,8 +49,8 @@ func TestNats(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	assert.Equal(t, k.Keys(), []string{"some.test.color"})
-	assert.Equal(t, k.Get("some.test.color"), "blue")
+	assert.Equal(t, []string{"some.test.color"}, k.Keys())
+	assert.Equal(t, "blue", k.Get("some.test.color"))
 
 	err = provider.Watch(func(event interface{}, err error) {
 		if err != nil {

tests/maps_test.go

@@ -103,16 +103,16 @@ var testMap3 = map[string]interface{}{
 func TestFlatten(t *testing.T) {
 	f, k := maps.Flatten(testMap, nil, delim)
 	assert.Equal(t, map[string]interface{}{
-		"parent.child.key":          123,
-		"parent.child.key.with.dot": 456,
-		"top":                       789,
-		"empty":                     map[string]interface{}{},
+		"parent.child.key":            123,
+		"parent.child.key~1with~1dot": 456,
+		"top":                         789,
+		"empty":                       map[string]interface{}{},
 	}, f)
 	assert.Equal(t, map[string][]string{
-		"parent.child.key":          {"parent", "child", "key"},
-		"parent.child.key.with.dot": {"parent", "child", "key.with.dot"},
-		"top":                       {"top"},
-		"empty":                     {"empty"},
+		"parent.child.key":            {"parent", "child", "key"},
+		"parent.child.key~1with~1dot": {"parent", "child", "key.with.dot"},
+		"top":                         {"top"},
+		"empty":                       {"empty"},
 	}, k)
 }
 
@@ -125,11 +125,11 @@ func BenchmarkFlatten(b *testing.B) {
 func TestUnflatten(t *testing.T) {
 	m, _ := maps.Flatten(testMap, nil, delim)
 	um := maps.Unflatten(m, delim)
-	assert.NotEqual(t, um, testMap)
+	assert.Equal(t, testMap, um)
 
 	m, _ = maps.Flatten(testMap2, nil, delim)
 	um = maps.Unflatten(m, delim)
-	assert.Equal(t, um, testMap2)
+	assert.Equal(t, testMap2, um)
 }
 
 func TestIntfaceKeysToStrings(t *testing.T) {