tinyauth/patches/nested_maps.diff

diff --git a/env/env_test.go b/env/env_test.go
index 7045569..365dc00 100644
--- a/env/env_test.go
+++ b/env/env_test.go
@@ -166,6 +166,38 @@ func TestDecode(t *testing.T) {
 				Foo: &struct{ Field string }{},
 			},
 		},
+		{
+			desc:    "map under the root key",
+			environ: []string{"TRAEFIK_FOO_BAR_FOOBAR_BARFOO=foo"},
+			element: &struct {
+				Foo map[string]struct {
+					Foobar struct {
+						Barfoo string
+					}
+				}
+			}{},
+			expected: &struct {
+				Foo map[string]struct {
+					Foobar struct {
+						Barfoo string
+					}
+				}
+			}{
+				Foo: map[string]struct {
+					Foobar struct {
+						Barfoo string
+					}
+				}{
+					"bar": {
+						Foobar: struct {
+							Barfoo string
+						}{
+							Barfoo: "foo",
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, test := range testCases {
diff --git a/parser/nodes_metadata.go b/parser/nodes_metadata.go
index 36946c1..0279705 100644
--- a/parser/nodes_metadata.go
+++ b/parser/nodes_metadata.go
@@ -75,8 +75,13 @@ func (m metadata) add(rootType reflect.Type, node *Node) error {
 	node.Kind = fType.Kind()
 	node.Tag = field.Tag
 
-	if fType.Kind() == reflect.Struct || fType.Kind() == reflect.Pointer && fType.Elem().Kind() == reflect.Struct ||
-		fType.Kind() == reflect.Map {
+	if node.Kind == reflect.String && len(node.Children) > 0 {
+		fType = reflect.TypeOf(struct{}{})
+		node.Kind = reflect.Struct
+	}
+
+	if node.Kind == reflect.Struct || node.Kind == reflect.Pointer && fType.Elem().Kind() == reflect.Struct ||
+		node.Kind == reflect.Map {
 		if len(node.Children) == 0 && !(field.Tag.Get(m.TagName) == TagLabelAllowEmpty || field.Tag.Get(m.TagName) == "-") {
 			return fmt.Errorf("%s cannot be a standalone element (type %s)", node.Name, fType)
 		}
@@ -90,11 +95,11 @@ func (m metadata) add(rootType reflect.Type, node *Node) error {
 		return nil
 	}
 
-	if fType.Kind() == reflect.Struct || fType.Kind() == reflect.Pointer && fType.Elem().Kind() == reflect.Struct {
+	if node.Kind == reflect.Struct || node.Kind == reflect.Pointer && fType.Elem().Kind() == reflect.Struct {
 		return m.browseChildren(fType, node)
 	}
 
-	if fType.Kind() == reflect.Map {
+	if node.Kind == reflect.Map {
 		if fType.Elem().Kind() == reflect.Interface {
 			addRawValue(node)
 			return nil
@@ -115,7 +120,7 @@ func (m metadata) add(rootType reflect.Type, node *Node) error {
 		return nil
 	}
 
-	if fType.Kind() == reflect.Slice {
+	if node.Kind == reflect.Slice {
 		if m.AllowSliceAsStruct && field.Tag.Get(TagLabelSliceAsStruct) != "" {
 			return m.browseChildren(fType.Elem(), node)
 		}
@@ -129,7 +134,7 @@ func (m metadata) add(rootType reflect.Type, node *Node) error {
 		return nil
 	}
 
-	return fmt.Errorf("invalid node %s: %v", node.Name, fType.Kind())
+	return fmt.Errorf("invalid node %s: %v", node.Name, node.Kind)
 }
 
 func (m metadata) findTypedField(rType reflect.Type, node *Node) (reflect.StructField, error) {