fix(build): copy frontend assets to embed dir when frontend:dir is non-default

Wails Documentation Agent · Wails Documentation Agent · commit deeeef110f34 · 2026-04-24T23:14:16.000+10:00
When frontend:dir is set to a directory other than the default "frontend", the built assets end up in the custom directory's dist/ folder but the go:embed directive in main.go still points to frontend/dist. This causes the built binary to have no frontend assets. After BuildFrontend completes, detect if the frontend dir differs from the embed target and copy the built assets to the embed directory so the Go compiler can find them. Fixes #5034
diff --git a/v2/pkg/commands/build/build.go b/v2/pkg/commands/build/build.go
@@ -141,6 +141,10 @@ func Build(options *Options) (string, error) {
 		if err != nil {
 			return "", err
 		}
+
+		if err := syncFrontendAssetsToEmbedDir(options); err != nil {
+			return "", err
+		}
 	}
 
 	compileBinary := ""
@@ -192,6 +196,89 @@ func CreateEmbedDirectories(cwd string, buildOptions *Options) error {
 	return nil
 }
 
+func syncFrontendAssetsToEmbedDir(options *Options) error {
+	frontendDir := options.ProjectData.GetFrontendDir()
+	defaultEmbedDir := filepath.Join(options.ProjectData.Path, "frontend")
+	absFrontendDir, err := filepath.Abs(frontendDir)
+	if err != nil {
+		return err
+	}
+	absDefaultDir, err := filepath.Abs(defaultEmbedDir)
+	if err != nil {
+		return err
+	}
+
+	if absFrontendDir == absDefaultDir {
+		return nil
+	}
+
+	embedDetails, err := staticanalysis.GetEmbedDetails(options.ProjectData.Path)
+	if err != nil {
+		return nil
+	}
+
+	for _, ed := range embedDetails {
+		if filepath.Ext(ed.GetFullPath()) != "" {
+			continue
+		}
+		relPath, err := filepath.Rel(options.ProjectData.Path, ed.GetFullPath())
+		if err != nil {
+			continue
+		}
+		if !strings.HasPrefix(relPath, "frontend"+string(filepath.Separator)) {
+			continue
+		}
+		frontendSubPath := strings.TrimPrefix(relPath, "frontend"+string(filepath.Separator))
+		srcDir := filepath.Join(absFrontendDir, frontendSubPath)
+
+		if !fs.DirExists(srcDir) {
+			continue
+		}
+
+		destDir := ed.GetFullPath()
+		if fs.DirExists(destDir) {
+			if err := os.RemoveAll(destDir); err != nil {
+				return fmt.Errorf("failed to clear embed directory %s: %w", destDir, err)
+			}
+		}
+		if err := fs.MkDirs(destDir, 0o755); err != nil {
+			return fmt.Errorf("failed to create embed directory %s: %w", destDir, err)
+		}
+		if err := copyDirContents(srcDir, destDir); err != nil {
+			return fmt.Errorf("failed to copy frontend assets from %s to %s: %w", srcDir, destDir, err)
+		}
+	}
+	return nil
+}
+
+func copyDirContents(src, dst string) error {
+	entries, err := os.ReadDir(src)
+	if err != nil {
+		return err
+	}
+	for _, entry := range entries {
+		srcPath := filepath.Join(src, entry.Name())
+		dstPath := filepath.Join(dst, entry.Name())
+		if entry.IsDir() {
+			if err := fs.MkDirs(dstPath, 0o755); err != nil {
+				return err
+			}
+			if err := copyDirContents(srcPath, dstPath); err != nil {
+				return err
+			}
+		} else {
+			data, err := os.ReadFile(srcPath)
+			if err != nil {
+				return err
+			}
+			if err := os.WriteFile(dstPath, data, 0o644); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 func fatal(message string) {
 	printer := pterm.PrefixPrinter{
 		MessageStyle: &pterm.ThemeDefault.FatalMessageStyle,
diff --git a/v2/pkg/commands/build/sync_test.go b/v2/pkg/commands/build/sync_test.go
@@ -0,0 +1,47 @@
+package build
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCopyDirContents(t *testing.T) {
+	srcDir := t.TempDir()
+	dstDir := t.TempDir()
+
+	files := []struct {
+		path    string
+		content string
+	}{
+		{"index.html", "<html></html>"},
+		{"assets/main.js", "console.log('hi')"},
+		{"assets/style.css", "body {}"},
+		{"assets/sub/deep.txt", "deep"},
+	}
+
+	for _, f := range files {
+		fullPath := filepath.Join(srcDir, f.path)
+		if err := os.MkdirAll(filepath.Dir(fullPath), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(fullPath, []byte(f.content), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	if err := copyDirContents(srcDir, dstDir); err != nil {
+		t.Fatalf("copyDirContents() error = %v", err)
+	}
+
+	for _, f := range files {
+		data, err := os.ReadFile(filepath.Join(dstDir, f.path))
+		if err != nil {
+			t.Errorf("file %s not found in destination: %v", f.path, err)
+			continue
+		}
+		if string(data) != f.content {
+			t.Errorf("file %s: got %q, want %q", f.path, string(data), f.content)
+		}
+	}
+}
