fix: Only strip the first "." from the path passed to deepGet

This makes it possible to use the empty string as a map key.

Author: rhansen

internal/template/reflect.go

@@ -6,18 +6,6 @@ import (
 	"strings"
 )
 
-func stripPrefix(s, prefix string) string {
-	path := s
-	for {
-		if strings.HasPrefix(path, ".") {
-			path = path[1:]
-			continue
-		}
-		break
-	}
-	return path
-}
-
 func deepGetImpl(v reflect.Value, path []string) interface{} {
 	if !v.IsValid() {
 		log.Printf("invalid value\n")
@@ -40,7 +28,7 @@ func deepGetImpl(v reflect.Value, path []string) interface{} {
 func deepGet(item interface{}, path string) interface{} {
 	var parts []string
 	if path != "" {
-		parts = strings.Split(stripPrefix(path, "."), ".")
+		parts = strings.Split(strings.TrimPrefix(path, "."), ".")
 	}
 	return deepGetImpl(reflect.ValueOf(item), parts)
 }

internal/template/reflect_test.go

@@ -34,7 +34,7 @@ func TestDeepGetSimpleDotPrefix(t *testing.T) {
 	item := context.RuntimeContainer{
 		ID: "expected",
 	}
-	value := deepGet(item, "...ID")
+	value := deepGet(item, ".ID")
 	assert.IsType(t, "", value)
 
 	assert.Equal(t, "expected", value)
@@ -51,3 +51,31 @@ func TestDeepGetMap(t *testing.T) {
 
 	assert.Equal(t, "value", value)
 }
+
+func TestDeepGet(t *testing.T) {
+	for _, tc := range []struct {
+		desc string
+		item interface{}
+		path string
+		want interface{}
+	}{
+		{
+			"map key empty string",
+			map[string]map[string]map[string]string{
+				"": map[string]map[string]string{
+					"": map[string]string{
+						"": "foo",
+					},
+				},
+			},
+			"...",
+			"foo",
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			got := deepGet(tc.item, tc.path)
+			assert.IsType(t, tc.want, got)
+			assert.Equal(t, tc.want, got)
+		})
+	}
+}