Only send `completionItem/resolve` if supported (#2624)

* Oni will hang indefinitely if the language server simply chooses to
ignore unsupported requests.
* This can be avoided if the server provides correct capabilities and
we actually check them before making the request.

browser/src/Services/Completion/CompletionsRequestor.ts

@@ -10,6 +10,7 @@ import * as Log from "oni-core-logging"
 import * as Helpers from "./../../Plugins/Api/LanguageClient/LanguageClientHelpers"
 
 import { LanguageManager } from "./../Language"
+import { IServerCapabilities } from "./../Language/ServerCapabilities"
 
 export interface CompletionsRequestContext {
     language: string
@@ -86,6 +87,12 @@ export class LanguageServiceCompletionsRequestor implements ICompletionsRequesto
         filePath: string,
         completionItem: types.CompletionItem,
     ): Promise<types.CompletionItem> {
+        const caps: IServerCapabilities = await this._languageManager.getCapabilitiesForLanguage(
+            language,
+        )
+        if (!caps.completionProvider.resolveProvider) {
+            return completionItem
+        }
         let result
         try {
             result = await this._languageManager.sendLanguageServerRequest(

browser/test/Services/Completion/CompletionsRequestorTests.ts

@@ -0,0 +1,60 @@
+import * as assert from "assert"
+import * as sinon from "sinon"
+
+import { LanguageServiceCompletionsRequestor } from "./../../../src/Services/Completion/CompletionsRequestor"
+import { LanguageManager } from "./../../../src/Services/Language"
+
+describe("LanguageServiceCompletionsRequestor", () => {
+    describe("getCompletionDetails", () => {
+        let completionItem: any
+        let completionDetails: any
+        let languageManager: any
+        let requestor: any
+
+        beforeEach(() => {
+            completionItem = sinon.stub()
+            completionDetails = sinon.stub()
+            languageManager = sinon.createStubInstance(LanguageManager)
+            languageManager.sendLanguageServerRequest.resolves(completionDetails)
+            requestor = new LanguageServiceCompletionsRequestor(languageManager)
+        })
+
+        it("doesn't send the request if the server is incapable", async () => {
+            languageManager.getCapabilitiesForLanguage.resolves({
+                completionProvider: { resolveProvider: false },
+            })
+
+            const returnedDetails = await requestor.getCompletionDetails(
+                "mocklang",
+                "mockpath",
+                completionItem as any,
+            )
+
+            sinon.assert.calledWithExactly(languageManager.getCapabilitiesForLanguage, "mocklang")
+            sinon.assert.notCalled(languageManager.sendLanguageServerRequest)
+            assert.strictEqual(returnedDetails, completionItem)
+        })
+
+        it("requests completion details if server is capable", async () => {
+            languageManager.getCapabilitiesForLanguage.resolves({
+                completionProvider: { resolveProvider: true },
+            })
+
+            const returnedDetails = await requestor.getCompletionDetails(
+                "mocklang",
+                "mockpath",
+                completionItem as any,
+            )
+
+            sinon.assert.calledWithExactly(languageManager.getCapabilitiesForLanguage, "mocklang")
+            sinon.assert.calledWithExactly(
+                languageManager.sendLanguageServerRequest,
+                "mocklang",
+                "mockpath",
+                "completionItem/resolve",
+                completionItem,
+            )
+            assert.strictEqual(returnedDetails, completionDetails)
+        })
+    })
+})

package.json

@@ -928,7 +928,7 @@
         "@types/redux-mock-store": "^1.0.0",
         "@types/rimraf": "^2.0.2",
         "@types/shelljs": "^0.7.7",
-        "@types/sinon": "1.16.32",
+        "@types/sinon": "5.0.5",
         "@types/webgl2": "^0.0.3",
         "autoprefixer": "6.4.0",
         "aws-sdk": "^2.202.0",
@@ -992,7 +992,7 @@
         "remap-istanbul": "^0.10.1",
         "reselect": "3.0.1",
         "rxjs": "5.5.8",
-        "sinon": "1.17.6",
+        "sinon": "5.0.5",
         "spectron": "^3.8.0",
         "style-loader": "0.18.2",
         "sudo-prompt": "7.1.1",