refactor(amazonq): separate edits from completion code path (aws#7793)

## Problem

related aws/language-servers#2058

Edits as a newly introduced feature, previously the implementation was
living in the same flow as Completion. However the 2 suggestion types
have few different product requirements, thus we decided to completely
separate these 2 suggestions out in terms of their code path.

Key difference

- Language server will process Completion request on receiving request
from IDE clients, and will BLOCK following requests if in-flight request
is not fulfilled yet. Edits, on the other hand, it debounces/delay the
execution time for the sake of "latest" file context to ensure the
suggestion reflects the CORRECT changes users attempt to make.
- Triggering heuristic. For example, Completion is not supposed to be
invoked when users are deleting the code, whereas Edits allow such
scenario to go through.


## Solution
- Introduce a new `onEditCompletion` language server API which is purely
for Edits suggestion.
- Invoke 2 Flare API and serve the response which first arrives (First
come first served).
- Allow Edits suggestion on code deletion




---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: Will-ShaoHua

packages/amazonq/src/app/inline/completion.ts

@@ -276,12 +276,6 @@ export class AmazonQInlineCompletionItemProvider implements InlineCompletionItem
 
         // yield event loop to let the document listen catch updates
         await sleep(1)
-        // prevent user deletion invoking auto trigger
-        // this is a best effort estimate of deletion
-        if (this.documentEventListener.isLastEventDeletion(document.uri.fsPath)) {
-            getLogger().debug('Skip auto trigger when deleting code')
-            return []
-        }
 
         let logstr = `GenerateCompletion metadata:\\n`
         try {
@@ -370,8 +364,8 @@ export class AmazonQInlineCompletionItemProvider implements InlineCompletionItem
                 },
                 token,
                 isAutoTrigger,
-                getAllRecommendationsOptions,
-                this.documentEventListener.getLastDocumentChangeEvent(document.uri.fsPath)?.event
+                this.documentEventListener,
+                getAllRecommendationsOptions
             )
             // get active item from session for displaying
             const items = this.sessionManager.getActiveRecommendation()
@@ -404,21 +398,24 @@ ${itemLog}
 
             const cursorPosition = document.validatePosition(position)
 
-            if (position.isAfter(editor.selection.active)) {
-                const params: LogInlineCompletionSessionResultsParams = {
-                    sessionId: session.sessionId,
-                    completionSessionResult: {
-                        [itemId]: {
-                            seen: false,
-                            accepted: false,
-                            discarded: true,
+            // Completion will not be rendered if users cursor moves to a position which is before the position when the service is invoked
+            if (items.length > 0 && !items[0].isInlineEdit) {
+                if (position.isAfter(editor.selection.active)) {
+                    const params: LogInlineCompletionSessionResultsParams = {
+                        sessionId: session.sessionId,
+                        completionSessionResult: {
+                            [itemId]: {
+                                seen: false,
+                                accepted: false,
+                                discarded: true,
+                            },
                         },
-                    },
+                    }
+                    this.languageClient.sendNotification(this.logSessionResultMessageName, params)
+                    this.sessionManager.clear()
+                    logstr += `- cursor moved behind trigger position. Discarding completion suggestion...`
+                    return []
                 }
-                this.languageClient.sendNotification(this.logSessionResultMessageName, params)
-                this.sessionManager.clear()
-                logstr += `- cursor moved behind trigger position. Discarding suggestion...`
-                return []
             }
 
             // delay the suggestion rendeing if user is actively typing

packages/amazonq/src/app/inline/recommendationService.ts

@@ -2,12 +2,12 @@
  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
  * SPDX-License-Identifier: Apache-2.0
  */
-import * as vscode from 'vscode'
 import {
     InlineCompletionListWithReferences,
     InlineCompletionWithReferencesParams,
     inlineCompletionWithReferencesRequestType,
     TextDocumentContentChangeEvent,
+    editCompletionRequestType,
 } from '@aws/language-server-runtimes/protocol'
 import { CancellationToken, InlineCompletionContext, Position, TextDocument } from 'vscode'
 import { LanguageClient } from 'vscode-languageclient'
@@ -21,6 +21,7 @@ import {
 import { TelemetryHelper } from './telemetryHelper'
 import { ICursorUpdateRecorder } from './cursorUpdateManager'
 import { getLogger } from 'aws-core-vscode/shared'
+import { DocumentEventListener } from './documentEventListener'
 import { getOpenFilesInWindow } from 'aws-core-vscode/utils'
 import { asyncCallWithTimeout } from '../../util/timeoutUtil'
 
@@ -66,9 +67,11 @@ export class RecommendationService {
         context: InlineCompletionContext,
         token: CancellationToken,
         isAutoTrigger: boolean,
-        options: GetAllRecommendationsOptions = { emitTelemetry: true, showUi: true },
-        documentChangeEvent?: vscode.TextDocumentChangeEvent
+        documentEventListener: DocumentEventListener,
+        options: GetAllRecommendationsOptions = { emitTelemetry: true, showUi: true }
     ) {
+        const documentChangeEvent = documentEventListener?.getLastDocumentChangeEvent(document.uri.fsPath)?.event
+
         // Record that a regular request is being made
         this.cursorUpdateRecorder?.recordCompletionRequest()
         const documentChangeParams = documentChangeEvent
@@ -119,7 +122,51 @@ export class RecommendationService {
             })
             const t0 = performance.now()
 
-            const result = await this.getRecommendationsWithTimeout(languageClient, request, token)
+            // Best effort estimate of deletion
+            const isTriggerByDeletion = documentEventListener.isLastEventDeletion(document.uri.fsPath)
+
+            const ps: Promise<InlineCompletionListWithReferences>[] = []
+            /**
+             * IsTriggerByDeletion is to prevent user deletion invoking Completions.
+             * PartialResultToken is not a hack for now since only Edits suggestion use partialResultToken across different calls of [getAllRecommendations],
+             * Completions use PartialResultToken with single 1 call of [getAllRecommendations].
+             * Edits leverage partialResultToken to achieve EditStreak such that clients can pull all continuous suggestions generated by the model within 1 EOS block.
+             */
+            if (!isTriggerByDeletion && !request.partialResultToken) {
+                const completionPromise: Promise<InlineCompletionListWithReferences> = languageClient.sendRequest(
+                    inlineCompletionWithReferencesRequestType.method,
+                    request,
+                    token
+                )
+                ps.push(completionPromise)
+            }
+
+            /**
+             * Though Edit request is sent on keystrokes everytime, the language server will execute the request in a debounced manner so that it won't be immediately executed.
+             */
+            const editPromise: Promise<InlineCompletionListWithReferences> = languageClient.sendRequest(
+                editCompletionRequestType.method,
+                request,
+                token
+            )
+            ps.push(editPromise)
+
+            /**
+             * First come first serve, ideally we should simply return the first response returned. However there are some caviar here because either
+             * (1) promise might be returned early without going through service
+             * (2) some users are not enabled with edits suggestion, therefore service will return empty result without passing through the model
+             * With the scenarios listed above or others, it's possible that 1 promise will ALWAYS win the race and users will NOT get any suggestion back.
+             * This is the hack to return first "NON-EMPTY" response
+             */
+            let result = await Promise.race(ps)
+            if (ps.length > 1 && result.items.length === 0) {
+                for (const p of ps) {
+                    const r = await p
+                    if (r.items.length > 0) {
+                        result = r
+                    }
+                }
+            }
 
             getLogger().info('Received inline completion response from LSP: %O', {
                 sessionId: result.sessionId,

packages/amazonq/test/unit/amazonq/apps/inline/recommendationService.test.ts

@@ -14,6 +14,10 @@ import { createMockDocument } from 'aws-core-vscode/test'
 import { CursorUpdateManager } from '../../../../../src/app/inline/cursorUpdateManager'
 import { CodeWhispererStatusBarManager } from 'aws-core-vscode/codewhisperer'
 import { globals } from 'aws-core-vscode/shared'
+import { DocumentEventListener } from '../../../../../src/app/inline/documentEventListener'
+
+const completionApi = 'aws/textDocument/inlineCompletionWithReferences'
+const editApi = 'aws/textDocument/editCompletion'
 
 describe('RecommendationService', () => {
     let languageClient: LanguageClient
@@ -28,6 +32,10 @@ describe('RecommendationService', () => {
     const mockPosition = { line: 0, character: 0 } as Position
     const mockContext = { triggerKind: InlineCompletionTriggerKind.Automatic, selectedCompletionInfo: undefined }
     const mockToken = { isCancellationRequested: false } as CancellationToken
+    const mockDocumentEventListener = {
+        isLastEventDeletion: (filepath: string) => false,
+        getLastDocumentChangeEvent: (filepath: string) => undefined,
+    } as DocumentEventListener
     const mockInlineCompletionItemOne = {
         insertText: 'ItemOne',
     } as InlineCompletionItem
@@ -134,12 +142,19 @@ describe('RecommendationService', () => {
                 mockPosition,
                 mockContext,
                 mockToken,
-                true
+                true,
+                mockDocumentEventListener
             )
 
             // Verify sendRequest was called with correct parameters
-            assert(sendRequestStub.calledOnce)
-            const requestArgs = sendRequestStub.firstCall.args[1]
+            const cs = sendRequestStub.getCalls()
+            const completionCalls = cs.filter((c) => c.firstArg === completionApi)
+            const editCalls = cs.filter((c) => c.firstArg === editApi)
+            assert.strictEqual(cs.length, 2)
+            assert.strictEqual(completionCalls.length, 1)
+            assert.strictEqual(editCalls.length, 1)
+
+            const requestArgs = completionCalls[0].args[1]
             assert.deepStrictEqual(requestArgs, {
                 textDocument: {
                     uri: 'file:///test.py',
@@ -177,12 +192,19 @@ describe('RecommendationService', () => {
                 mockPosition,
                 mockContext,
                 mockToken,
-                true
+                true,
+                mockDocumentEventListener
             )
 
             // Verify sendRequest was called with correct parameters
-            assert(sendRequestStub.calledTwice)
-            const firstRequestArgs = sendRequestStub.firstCall.args[1]
+            const cs = sendRequestStub.getCalls()
+            const completionCalls = cs.filter((c) => c.firstArg === completionApi)
+            const editCalls = cs.filter((c) => c.firstArg === editApi)
+            assert.strictEqual(cs.length, 3)
+            assert.strictEqual(completionCalls.length, 2)
+            assert.strictEqual(editCalls.length, 1)
+
+            const firstRequestArgs = completionCalls[0].args[1]
             const expectedRequestArgs = {
                 textDocument: {
                     uri: 'file:///test.py',
@@ -192,7 +214,7 @@ describe('RecommendationService', () => {
                 documentChangeParams: undefined,
                 openTabFilepaths: [],
             }
-            const secondRequestArgs = sendRequestStub.secondCall.args[1]
+            const secondRequestArgs = completionCalls[1].args[1]
             assert.deepStrictEqual(firstRequestArgs, expectedRequestArgs)
             assert.deepStrictEqual(secondRequestArgs, {
                 ...expectedRequestArgs,
@@ -218,7 +240,8 @@ describe('RecommendationService', () => {
                 mockPosition,
                 mockContext,
                 mockToken,
-                true
+                true,
+                mockDocumentEventListener
             )
 
             // Verify recordCompletionRequest was called
@@ -235,6 +258,7 @@ describe('RecommendationService', () => {
                 mockContext,
                 mockToken,
                 true,
+                mockDocumentEventListener,
                 {
                     showUi: false,
                     emitTelemetry: true,
@@ -254,7 +278,8 @@ describe('RecommendationService', () => {
                 mockPosition,
                 mockContext,
                 mockToken,
-                true
+                true,
+                mockDocumentEventListener
             )
 
             // Verify UI methods were called
@@ -286,6 +311,7 @@ describe('RecommendationService', () => {
                     mockContext,
                     mockToken,
                     true,
+                    mockDocumentEventListener,
                     options
                 )