Announce supported capabilities

[predragnikolic]

LSP clients(like Sublime Text), won't send server requests if the server didn't announce support for those requests through capabilities.

Currently the Volar server only announces this capability:
https://github.com/johnsoncodehk/volar/blob/8733e9483389d9567525f0493b56697fe8f2c35a/packages/server/src/index.ts#L34-L36

But it should actually include lots of other capabilities.
Here is an example of what the Vetur server returns:

Note: I accidentally lowercased all the object keys :)

{
	"capabilities": {
		"foldingrangeprovider": true,
		"codeactionprovider": {
			"codeactionkinds": ["quickfix", "refactor", "refactor.extract", "refactor.inline", "refactor.rewrite", "source", "source.organizeimports"],
			"resolveprovider": true
		},
		"signaturehelpprovider": {
			"triggercharacters": ["("] 
		},
		"colorprovider": true,
		"semantictokensprovider": {
			"legend": {
				"tokenmodifiers": ["declaration", "static", "async", "readonly", "defaultlibrary", "local", "refvalue"],
				"tokentypes": ["class", "enum", "interface", "namespace", "typeparameter", "type", "parameter", "variable", "enummember", "property", "function", "method"]
			},
			"range": true,
			"full": true
		},
		"workspace": {
			"fileoperations": {
				"willrename": {
					"filters": [
						{
							"pattern": {
								"glob": "**/*.{ts,js,vue}"
							}
						}
					]
				}
			},
			"workspacefolders": {
				"changenotifications": true,
				"supported": true
			}
		},
		"completionprovider": {
			"triggercharacters": [".", ":", "<", "\"", "'", "/", "@", "*", " "],
			"resolveprovider": true
		},
		"hoverprovider": true,
		"executecommandprovider": {
			"commands": []
		},
		"documentlinkprovider": {
			"resolveprovider": false
		},
		"referencesprovider": true,
		"definitionprovider": true,
		"documenthighlightprovider": true,
		"textdocumentsync": {
			"didclose": {},
			"save": {},
			"didopen": {},
			"change": {
				"synckind": 2
			}
		},
		"documentformattingprovider": false,
		"documentsymbolprovider": true
	}
}

Additional context:

Even when I add a completion capability for completions:

	const result: vscode.InitializeResult = {
		capabilities: {
			textDocumentSync: vscode.TextDocumentSyncKind.Incremental,
			completionProvider: {
				triggerCharacters: ['.']
			}
		}
	};

When a LSP client sends a request to Volar,
Volar returns this error:

Client sends a request to volar:
:: --> LSP-volar textDocument/completion(5): {'position': {'line': 0, 'character': 0}, 'textDocument': {'uri': 'file:///home/predragnikolic/.config/sublime-text/Packages/LSP-volar/index.vue'}}

Volar sends back this:
:: <~~ LSP-volar 5: {'message': 'Unhandled method textDocument/completion', 'code': -32601}

So even when Volar has specified capabilities, the server still will not work with other LSP clients (just yet :). Do you have any idea why?

[johnsoncodehk]

You need to config which features should enable by initializationOptions in language client, because volar split language features to two TS language server to resolved request blocking. (#390)

See https://github.com/yaegassy/coc-volar/blob/master/src/index.ts#L129-L182.

[predragnikolic]

Based on the ServerInitializationOptions type,
https://github.com/johnsoncodehk/volar/blob/f52f672d4b6667971dbb1d23cc9116083be64563/packages/shared/src/types.ts#L6-L10
the initializationOptions.typescript.serverPath string is the only required option that needs to be provided in the initializationOptions.

I tried to supply only the initializationOptions.typescript.serverPath option,
and the server starts
but there are no signs of intellisense.

---

The initializationOptions.languageFeatures or initializationOptions.documentFeatures are not required based on theServerInitializationOptions type.

But reguardless I also tried adding both languageFeatures and documentFeatures in the initialization options,
but still no signs of intellisense.

Here is how my initializationOptions looked like:

// Settings in here override those in "LSP-volar/LSP-volar.sublime-settings"

{
	"command": ["${node_bin}", "/home/predragnikolic/Documents/sandbox/volar/packages/server/out/index.js", "--stdio"],
	"initializationOptions": {
		"typescript": {
			"serverPath": "/home/predragnikolic/.npm-global/lib/node_modules/typescript/lib/typescript.js",
		},
		"languageFeatures": {
			"references": true,
			"definition": true,
			"typeDefinition": true,
			"callHierarchy": false,
			"hover": true,
			"rename": true,
			"renameFileRefactoring": false,
			"signatureHelp": true,
			"codeAction": true,
			"completion": {
			  "defaultTagNameCase": "both",
			  "defaultAttrNameCase": "kebab",
			  "getDocumentNameCasesRequest": false,
			  "getDocumentSelectionRequest": false,
			},
			"documentHighlight": true,
			"documentLink": false,
			"codeLens": false,
			"semanticTokens": false,
			"schemaRequestService": false,
			"diagnostics": true
		},
		"documentFeatures": {
			"selectionRange": true,
			"foldingRange": true,
			"linkedEditingRange": false,
			"documentSymbol": true,
			"documentColor": true,
			"documentFormatting": {
				"defaultPrintWidth": 90
			}
		}
	}
}

---

I am not sure what I am doing wrong.

Even when the LSP client needs to send server capabilities in initialization options (which I think should not be a clients responsibility :) ),
the server would need to respond with a "correct" InitializeResult, which it currently doesn't.
By "correct" I mean to return all capabilities that the server in that current time supports. Currently Volar just returns textDocumentSync options.

Additional question:

I saw the code in coc-volar and noticed that there are 3 separate language handlers.

Why is there a need to create 3 separate language handlers:
https://github.com/yaegassy/coc-volar/blob/553acb8670cb78f68b6b5ba760dc95d647f98e5d/src/index.ts#L60-L62
with different server capabilities for each?
https://github.com/yaegassy/coc-volar/blob/553acb8670cb78f68b6b5ba760dc95d647f98e5d/src/index.ts#L129-L182
What the difference between 'api', 'doc' and 'html'?

[johnsoncodehk]

Even when the LSP client needs to send server capabilities in initialization options (which I think should not be a clients responsibility :) ),

This is to support distribute features to multiple servers.

the server would need to respond with a "correct" InitializeResult, which it currently doesn't.

Volar register features after initialized to prevent request trigger before server ready. (https://github.com/johnsoncodehk/volar/blob/master/packages/server/src/registers/registerlanguageFeatures.ts)

I saw the code in coc-volar and noticed that there are 3 separate language handlers.

If all requests are processed on one server, all features will be blocked when the diagnosis is very slow. Auto-complete has a higher priority than diagnosis. Auto-complete should not be blocked, so I assign features to 2 servers (api, doc) according to whether the feature can be blocked. But this is not enough. In the api server, tag-auto-close feature is stateless, it is very fast, but it will be blocked by auto-complete, so I further allocated the stateless features to the html server.

languageFeatures, documentFeatures options allow the language client to decide how many servers to provide services. If you don't care about sensitivity, you can enable all features in one language server.

[predragnikolic]

@johnsoncodehk thanks you for your time!

I didn't knew that Volar supports dynamic registration,
that helped me a lot and it made the server work in Sublime Text.

[ElMassimo]

@predragnikolic I'm interested in using Volar in Sublime Text as well, are you planning to submit LSP Volar to Package Control?

[predragnikolic]

Hello @ElMassimo,

In short, I am not planning to push LSP-volar to Package Control,
but I was planning to invite collaborators to the LSP-volar repo. So hopefully other people can publish it to Package Control.

Anyone who is willing to help is more than welcome,
and I am more than happy to help with getting started. (just ping me :) )