Custom themes are not working

[anssit]

Steps to reproduce

1. Import the attached project my-app.zip to IDE
2. Open hello-world-view.ts in Designer

Actual behavior

Custom theme is not applied. For example, the padding defined in frontend/themes/myapp/views/hello-world-view.css is not applied.

Browser console log:

theme-bundle.js:1 Failed to load resource: the server responded with a status of 404 (Not Found)

Server side log:

INFO: Starting node process: node ./node_modules/rollup/dist/bin/rollup --config target/designer/rollup.config.js
Aug 30, 2021 11:02:15 AM com.vaadin.designer2.services.flow.NodeProcessRunner start
INFO: 

internal/modules/cjs/loader.js:883
  throw err;
  ^

Error: Cannot find module '/Users/anssit/Downloads/mun-app/node_modules/rollup/dist/bin/rollup'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)
    at Function.Module._load (internal/modules/cjs/loader.js:725:27)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
    at internal/main/run_main_module.js:17:47 {
  code: 'MODULE_NOT_FOUND',
  requireStack: []
}

Expected behavior

Custom theme is applied.

IDE, Designer and OS version

Designer 4.6.9
Project Vaadin version: 14.x (check also with 21.x)

[anssit]

After manually installing rollup for bundling the custom theme, the next error appears:

Uncaught ReferenceError: applyTheme$1 is not defined at theme-bundle.js:3

This might have to do with the following (in theme-bundle.js):

import { applyTheme as applyTheme$1 } from 'themes/com.vaadin.flow.theme.AbstractTheme.class/com.vaadin.flow.theme.AbstractTheme.class.generated.js';

Vaadin 14 uses a slightly different annotation for specifying the theme:

• @Theme(themeFolder = "myapp") V14
• @Theme(value = "myapp") V20

This may be the culprit.

[szolo]

This is still an issue. rollup does not work as expected.