Fix assets helpers

buffalo/cmd/updater/webpack.go

@@ -60,6 +60,10 @@ func WebpackCheck(r *Runner) error {
 
 	if !ask("Your webpack.config.js file is different from the latest Buffalo template.\nWould you like to replace yours with the latest template?") {
 		fmt.Println("\tSkipping webpack.config.js")
+		if !bytes.Contains(b, []byte("publicPath:")) {
+			r.Warnings = append(r.Warnings, `It seems your webpack.config.js file doesn't define a "publicPath". You need to define it MANUALLY in the "output" section to ensure assets helpers work correctly.
+See https://webpack.js.org/guides/public-path/`)
+		}
 		return nil
 	}
 

generators/assets/webpack/templates/webpack.config.js.tmpl

@@ -73,11 +73,12 @@ const configurator = {
 
   buildConfig: function(){
     const env = process.env.NODE_ENV || "development";
-
+    const ASSET_PATH = process.env.ASSET_PATH || "/assets/";
+
     var config = {
       mode: env,
       entry: configurator.entries(),
-      output: {filename: "[name].[hash].js", path: `${__dirname}/public/assets`},
+      output: {filename: "[name].[hash].js", path: `${__dirname}/public/assets`, publicPath: ASSET_PATH},
       plugins: configurator.plugins(),
       module: configurator.moduleOptions()
     }

render/template_helpers.go

@@ -27,9 +27,9 @@ func assetPathFor(file string) string {
 
 	filePath := assetMap[file]
 	if filePath == "" {
-		filePath = file
+		filePath = filepath.Join("/assets", file)
 	}
-	return filepath.ToSlash(filepath.Join("/assets", filePath))
+	return filepath.ToSlash(filePath)
 }
 
 type helperTag struct {

render/template_test.go

@@ -71,7 +71,7 @@ func Test_AssetPath(t *testing.T) {
 	}).Template
 
 	ioutil.WriteFile(filepath.Join(aDir, "manifest.json"), []byte(`{
-		"application.css": "application.aabbc123.css"
+		"application.css": "/assets/application.aabbc123.css"
 	}`), 0644)
 
 	for original, expected := range cases {