Modern Mode Build failed with multiple-pages setup

[WarWithinMe]

Version

3.0.0-rc.3

Reproduction link

https://codesandbox.io/s/k3ox9l4q05?module=%2Fvue.config.js&view=editor

Steps to reproduce

1. In vue.config.js, add a page config with directory in its "filename":

pages: {
    "privacy/index": {
      entry: "src/privacy.js",
      template: "privacy.html",
      filename: "privacy/index.html"
    }
}

2. Run vue-cli-service build --modern

What is expected?

vue-cli will generate the page under "dist/privacy/index.html" (dist is default outputDir)

What is actually happening?

vue-cli throws error and halts: (It seems like the issue exists only in Windows)

(node:15008) UnhandledPromiseRejectionWarning: Error: ENOENT: no such file or directory, open '......\dist\legacy-assets-privacy\index.html.json'

---

If the filename attribute doesn't contain directory, vue-cli will build successfully.

[Akryum]

Please provide an actual reproduction, codesandbox doesn't support vue-cli 3.

[WarWithinMe]

Try this setup:
Test.zip

I just found out that it builds successfully in OSX, guess the issue only exists in Windows system (Windows 10).

[nparley]

I am getting the same error on a OSX build. Seems to work fine on an app that was init via RC2, but fails with RC3. Upgrading the RC2 app to RC3 seems to work fine which is confusing.

[rocwang]

I think it is the same as #1791 which is fixed by #1792
The culprit is the Modern Mode Plugin assumes the "filename" option doesn't contain any subdirectories. See ModernModePlugin.js line 27 and line 52

[nparley]

OK upgrading to RC4 the legacy bundles now build, but not the modern bundles. They fail with:

(node:96496) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: ENOENT: no such file or directory, open '/.../dist/legacy-assets-index.html.json'

[nparley]

My problem was with sub directories see #1866

[yyx990803]

Can no longer reproduce with RC5 (working as expected).