[vue ui] Run tasks in vue ui, it adds `--mode` flag even I already have one in script command.

[laomao800]

Version

3.0.0-beta.16

Reproduction link

https://codesandbox.io/s/yp18qom2kx

Steps to reproduce

1. Already have a --mode flag in script command.

// package.json
{
  "scripts": {
    "build:dev": "vue-cli-service build --mode build-dev"
  },
  // ...
}

2. Run the task in ui will get this:

$ vue-cli-service build --mode build-dev --mode development --dest dist --target app --dashboard

It still adds a --mode flag even the command has one.

What is expected?

Use the correct mode value from command --mode.

What is actually happening?

Have two --mode in the command.

[voluntadpear]

Shouldn't each Task check for existing flags before pushing new flags to the args array?

For this particular case, the implementation of this task's onBeforeRun could check if each of the flags it's pushing already exists before trying to push them.

[Akryum]

What if you want to override an argument with the UI?

[voluntadpear]

I think having a checkbox on the UI to decide if we want to override arguments or not could be a good option. What do you think @Akryum?

Or maybe overriding arguments with the UI should be the correct behavior?

[Akryum]

I think putting checkboxes everywhere would really clutter the UX.

[laomao800]

@Akryum I already install the rc5.

In the UI tasks, it can remove the duplicate arguments now, but how could I use my own --mode value ?

I have some custom environment value in the .env.build-dev file.

[Akryum]

I've added (unset) options in the mode selects.