files.enableTrash preference

[akosyakov]

fix #4524: add files.enableTrash preference
fix #4334: allow to override default preference values:

• files.enableTrash is overridden to false as an example for the browser app
• one can override it programmatically: PreferenceSchemaProvider.getDefaultValue

[akosyakov]

theia-ide/theia-apps#159 to reconfigure docker image cc @marcdumais-work

[akosyakov]

fyi: not all strings in TS are just string, some can be used for property access, i.e myObject['myProp']
preference proxies are statically typed, one cannot use other prop names and type is properly determined for a prop, there is NO need for a constant. I had to remove it here because it confused compiler. The type of FILES_EXCLUDE_PREFERENCE now is 'files.exclude' | 'files.enableTrash', so compiler cannot derive any more a proper type where FILES_EXCLUDE_PREFERENCE is used.

cc @svor @kittaakos

[thegecko]

Hmm, getting the following error on this branch. Investigating....

[akosyakov]

@thegecko I've annotated the proxy factory as injectable to allow its subclassing in DI context. It seems to be used in process which does not load reflect metadata package.

[thegecko]

Ok, have you tried running this in electron? The js runtimes are quite restrictive

[akosyakov]

@thegecko good point, i will try

[akosyakov]

it's again because of cluster module. It uses proxy factories without installing reflect metadata package. I will move annotating proxy factories to browser module for now to make this PR work and then look into getting rid of cluster module.

[akosyakov]

@thegecko could you try again? It should work now

[thegecko]

Perfect!

I've successfully tested the settings override by using the following to open workspaces in the same window:

...
"preferences": {
    "workspace.preserveWindow": true
}
...

Nice work!

[AlexTugarev]

Works nicely!
Thanks for the preference feature! 🎉

[AlexTugarev]

@akosyakov, what's the issue with DCO check?

[akosyakov]

@AlexTugarev i also wonder what is wrong with it. Eclipse sign-off check is green, so it's good to merge?