Cannot set property 'filename' of undefined

[p-kuen]

Version

3.0.0-beta.11

Reproduction link

https://github.com/Patcher56/vue-flowy/blob/master/package.json

Steps to reproduce

1. yarn install
2. Type in yarn dev into terminal for building in development mode for target library and watch it for changes

What is expected?

Building my library in development mode and watch it for changes

What is actually happening?

An error (seems unhandled) appears:

⠋  Building for development as library (commonjs   umd)... ERROR  TypeError: Cannot set property 'filename' of undefined
TypeError: Cannot set property 'filename' of undefined
    at config.plugin.tap.args (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/lib/commands/build/resolveLibConfig.js:38:30)
    at Object.tap (/home/patrick/dev/vue-flowy/node_modules/webpack-chain/src/Plugin.js:19:24)
    at genConfig (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/lib/commands/build/resolveLibConfig.js:37:12)
    at module.exports (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/lib/commands/build/resolveLibConfig.js:99:5)
    at build (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/lib/commands/build/index.js:74:52)
    at Service.run (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/lib/Service.js:167:12)
    at Object.<anonymous> (/home/patrick/dev/vue-flowy/node_modules/@vue/cli-service/bin/vue-cli-service.js:22:9)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:689:10)
    at Module.load (internal/modules/cjs/loader.js:589:32)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

---

I am no pro with vue-cli-service or webpack. Can be possible that I misconfigured something.
Anyway it would be cool if there appears a better error description with the information what I did wrong.
Node version stable 10.0.0

[LinusBorg]

When building with --target lib you also have to define a --name for the generated UMD lib to use.