Allow Extensions To Contribute Language Specific Settings

[mjbvz]

Problem
To my knowledge, there is no well supported way for an extension to contribute language specific settings, like so:

    "[markdown]": {
           "amazingExtension.enableUnicornMode": false
     }

This actually works, but has some major issues:

• There is no way to specify a language specific setting in the contributes section's schema
• Entering the above configuration produces a warning for users
• To retrieve the setting, you have to write:

workspace.getConfiguration().get('[markdown]')['amazingExtension.enableUnicornMode']

Proposals

• Allow extensions to mark settings as being valid language specific settings.
• Add apis for better working with language specific settings

[jonhoo]

It'd be really neat if the flow worked the other way: if the extension didn't need to know about what language is currently being used, but instead vscode simply changed the setting appropriately for the extension when a file of a different type was opened. That would mean that things like vim.textwidth could also be set. Of course, this has the drawback of not being able to support multiple languages inside a single file, but it's not clear that that's something the vim extension for example cares about..

[sandy081]

@mjbvz You can contribute default language specific settings as follows

"configurationDefaults": {
	"[yaml]": {
		"editor.insertSpaces": true,
		"editor.tabSize": 2
	}
}

Above should work.

Regarding API, agreed that we need better support there.

[sandy081]

@mjbvz Ignore my earlier comment, I misunderstood with configuration defaults.
Yes, Currently only editor settings are supported as lang specific settings.

[DanTup]

It'd be really neat if the flow worked the other way: if the extension didn't need to know about what language is currently being used, but instead vscode simply changed the setting appropriately for the extension when a file of a different type was opened. That would mean that things like vim.textwidth could also be set.

I don't think this would work very well as you can have multiple files open side-by-side (there may also be side effects of firing config change events frequently if extensions currently only expect them to happen infrequently). I think it'd be much better to design something sane and have cooperation of extensions than try to make it work transparently.

[jeremychone]

On a side note, it might be good to add something to the doc. Took me a while to understand how to allow per language customization for my extension. Thanks to @mjbvz for this useful example.

Json validation/intellisense might be hard to solve (I am not familiar with Json schema), but adding a workspace.getConfiguration signature with languageId or Editor as argument would be pretty neat.