Merge pull request #4031 from gofiber/update-app.reloadviews-for-sub-app-reloading

Author: ReneWerner87

app.go

@@ -715,16 +715,30 @@ func (app *App) ReloadViews() error {
 	app.mutex.Lock()
 	defer app.mutex.Unlock()
 
-	if app.config.Views == nil {
-		return ErrNoViewEngineConfigured
+	apps := map[string]*App{"": app}
+	if app.mountFields != nil {
+		apps = app.mountFields.appList
 	}
 
-	if viewValue := reflect.ValueOf(app.config.Views); viewValue.Kind() == reflect.Pointer && viewValue.IsNil() {
-		return ErrNoViewEngineConfigured
+	var reloaded bool
+	for _, targetApp := range apps {
+		if targetApp == nil || targetApp.config.Views == nil {
+			continue
+		}
+
+		if viewValue := reflect.ValueOf(targetApp.config.Views); viewValue.Kind() == reflect.Pointer && viewValue.IsNil() {
+			continue
+		}
+
+		if err := targetApp.config.Views.Load(); err != nil {
+			return fmt.Errorf("fiber: failed to reload views: %w", err)
+		}
+
+		reloaded = true
 	}
 
-	if err := app.config.Views.Load(); err != nil {
-		return fmt.Errorf("fiber: failed to reload views: %w", err)
+	if !reloaded {
+		return ErrNoViewEngineConfigured
 	}
 
 	return nil
@@ -845,8 +859,7 @@ func (app *App) Use(args ...any) Router {
 
 	for _, prefix := range prefixes {
 		if subApp != nil {
-			app.mount(prefix, subApp)
-			return app
+			return app.mount(prefix, subApp)
 		}
 
 		app.register([]string{methodUse}, prefix, nil, handlers...)

app_test.go

@@ -36,6 +36,25 @@ import (
 	"github.com/valyala/fasthttp/fasthttputil"
 )
 
+type fileView struct {
+	path    string
+	content string
+	loads   int
+}
+
+func (v *fileView) Load() error {
+	contents, err := os.ReadFile(v.path)
+	if err != nil {
+		return fmt.Errorf("read template: %w", err)
+	}
+
+	v.content = string(contents)
+	v.loads++
+	return nil
+}
+
+func (*fileView) Render(io.Writer, string, any, ...string) error { return nil }
+
 func testEmptyHandler(_ Ctx) error {
 	return nil
 }
@@ -2047,6 +2066,77 @@ func Test_App_ReloadViews_InterfaceNilPointer(t *testing.T) {
 	require.ErrorIs(t, err, ErrNoViewEngineConfigured)
 }
 
+func Test_App_ReloadViews_MountedViews(t *testing.T) {
+	t.Parallel()
+	tempDir := t.TempDir()
+	templatePath := filepath.Join(tempDir, "template.html")
+
+	require.NoError(t, os.WriteFile(templatePath, []byte("before"), 0o600))
+
+	view := &fileView{path: templatePath}
+	subApp := New(Config{Views: view})
+	app := New()
+	app.Use("/sub", subApp)
+
+	require.NoError(t, view.Load())
+	initialLoads := view.loads
+	require.Equal(t, "before", view.content)
+
+	require.NoError(t, os.WriteFile(templatePath, []byte("after"), 0o600))
+	require.NoError(t, app.ReloadViews())
+
+	require.Equal(t, "after", view.content)
+	require.Greater(t, view.loads, initialLoads)
+}
+
+func Test_App_ReloadViews_MountedViews_Error(t *testing.T) {
+	t.Parallel()
+	expectedErr := errors.New("sub view error")
+	subView := &countingView{loadErr: expectedErr}
+	subApp := New(Config{Views: subView})
+	app := New()
+	app.Use("/sub", subApp)
+
+	err := app.ReloadViews()
+	require.ErrorIs(t, err, expectedErr)
+}
+
+func Test_App_ReloadViews_MountedViews_MultipleApps(t *testing.T) {
+	t.Parallel()
+	viewA := &countingView{}
+	viewB := &countingView{}
+	subAppA := New(Config{Views: viewA})
+	subAppB := New(Config{Views: viewB})
+	app := New()
+	app.Use("/a", subAppA)
+	app.Use("/b", subAppB)
+
+	initialLoadsA := viewA.loads
+	initialLoadsB := viewB.loads
+
+	require.NoError(t, app.ReloadViews())
+
+	require.Equal(t, initialLoadsA+1, viewA.loads)
+	require.Equal(t, initialLoadsB+1, viewB.loads)
+}
+
+func Test_App_ReloadViews_MountedViews_WithParentViews(t *testing.T) {
+	t.Parallel()
+	parentView := &countingView{}
+	subView := &countingView{}
+	subApp := New(Config{Views: subView})
+	app := New(Config{Views: parentView})
+	app.Use("/sub", subApp)
+
+	initialParentLoads := parentView.loads
+	initialSubLoads := subView.loads
+
+	require.NoError(t, app.ReloadViews())
+
+	require.Equal(t, initialParentLoads+1, parentView.loads)
+	require.Equal(t, initialSubLoads+1, subView.loads)
+}
+
 // go test -run Test_App_Init_Error_View
 func Test_App_Init_Error_View(t *testing.T) {
 	t.Parallel()

group.go

@@ -96,8 +96,7 @@ func (grp *Group) Use(args ...any) Router {
 
 	for _, prefix := range prefixes {
 		if subApp != nil {
-			grp.mount(prefix, subApp)
-			return grp
+			return grp.mount(prefix, subApp)
 		}
 
 		grp.app.register([]string{methodUse}, getGroupPath(grp.Prefix, prefix), grp, handlers...)

mount.go

@@ -45,13 +45,15 @@ func (app *App) mount(prefix string, subApp *App) Router {
 		prefix = "/"
 	}
 
+	app.mutex.Lock()
 	// Support for configs of mounted-apps and sub-mounted-apps
 	for mountedPrefixes, subApp := range subApp.mountFields.appList {
 		path := getGroupPath(prefix, mountedPrefixes)
 
 		subApp.mountFields.mountPath = path
 		app.mountFields.appList[path] = subApp
 	}
+	app.mutex.Unlock()
 
 	// register mounted group
 	mountGroup := &Group{Prefix: prefix, app: subApp}
@@ -75,13 +77,15 @@ func (grp *Group) mount(prefix string, subApp *App) Router {
 		groupPath = "/"
 	}
 
+	grp.app.mutex.Lock()
 	// Support for configs of mounted-apps and sub-mounted-apps
 	for mountedPrefixes, subApp := range subApp.mountFields.appList {
 		path := getGroupPath(groupPath, mountedPrefixes)
 
 		subApp.mountFields.mountPath = path
 		grp.app.mountFields.appList[path] = subApp
 	}
+	grp.app.mutex.Unlock()
 
 	// register mounted group
 	mountGroup := &Group{Prefix: groupPath, app: subApp}