storybook: Windows staticDirs issue - Storybook not loading assets despite path seemingly correct

Describe the bug On a Windows machine the staticDirs build with the expected structure:

dist/
    storybook/
        assets/
            imgs/
                imgs_sub/
                    image.png
            svgs/
                icon.svg

Then when we run npm run start, Storybook starts and appears to be working fine, but none of the static assets can be found. When looking at the network it seems to be requesting the correct paths:

http://localhost:6006/assets/imgs/imgs_sub/image.png http://localhost:6006/assets/svgs/icon.svg

But it’s returning a 404. If I go direct to that path it also doesn’t load.

main.js looks like this:

module.exports = {
  stories: ['../src/**/*.stories.ts'],
  addons: ['@storybook/addon-actions', '@storybook/addon-links', '@storybook/addon-a11y', '@storybook/addon-knobs'],
  staticDirs: [
    '../src/assets',
    { from: '../projects/icons/svgs', to: './assets/svgs' },
    { from: '../projects/images', to: './assets/imgs' }
  ],
  core: {
    builder: 'webpack5'
  },
  angularOptions: {
    enableIvy: false
  }
};

Debugging server-statics.js returns the following:

_arg$split = [".\projects\icons\svgs",".\assets\svgs"]
target=".\assets\svgs"
staticDir="./.\projects\icons\svgs"
staticPath="C:\Users\user\IdeaProjects\repo\projects\icons\svgs"
targetDir="./.\assets\svgs"
targetEndpoint="/.\assets\svgs"

and for imgs

_arg$split = [".\projects\images",".\assets\imgs"]
target=".\assets\imgs"
staticDir="./.\projects\images"
staticPath="C:\Users\user\IdeaProjects\repo\projects\images"
targetDir="./.\assets\imgs"
targetEndpoint="/.\assets\imgs"

If I remove the dot from main.js, like so, then the build errors:

staticDirs: [
    '../src/assets',
    { from: '../projects/icons/svgs', to: '/assets/svgs' },
    { from: '../projects/images', to: '/assets/imgs' }
],

Error returned:

info => Copying static files: C:\Users\user\IdeaProjects\repo\src\assets at C:\Users\user\IdeaProjects\repo\dist\storybook\
C:\Users\user\IdeaProjects\repo\node_modules\@storybook\core-server\dist\cjs\utils\server-statics.js:118
    throw new Error((0, _tsDedent.default)((0, _chalk.default)`
          ^

Error: Failed to load static files, no such directory: C:\Users\user\IdeaProjects\repo\projects\icons\svgs:\assets\svgs

System

Environment Info:

  System:
    OS: Windows 10 10.0.19044
    CPU: (8) x64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
  Binaries:
    Node: 16.13.2 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.22.17 - ~\IdeaProjects\repo\node_modules\.bin\yarn.CMD
    npm: 6.14.15 - ~\IdeaProjects\repo\node_modules\.bin\npm.CMD
  Browsers:
    Chrome: 97.0.4692.71
    Edge: Spartan (44.19041.1266.0), Chromium (97.0.1072.62)
  npmPackages:
    @storybook/addon-a11y: ^6.4.13 => 6.4.13
    @storybook/addon-actions: ^6.4.13 => 6.4.13
    @storybook/addon-knobs: 6.2.9 => 6.2.9
    @storybook/addon-links: ^6.4.13 => 6.4.13
    @storybook/addons: ^6.4.13 => 6.4.13
    @storybook/angular: ^6.4.13 => 6.4.13
    @storybook/builder-webpack5: ^6.4.13 => 6.4.13
    @storybook/manager-webpack5: ^6.4.13 => 6.4.13