From ac0b574dbd40b28260e496d32a592db0b44f3e4e Mon Sep 17 00:00:00 2001
From: Ulugbek Abdullaev <ulugbekna@gmail.com>
Date: Wed, 16 Jul 2025 16:56:39 +0200
Subject: [PATCH] nes: make cache delay configurable (#266)

---
 .../src/extension/inlineEdits/node/nextEditProvider.ts    | 8 ++++----
 .../platform/configuration/common/configurationService.ts | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/extensions/copilot/src/extension/inlineEdits/node/nextEditProvider.ts b/extensions/copilot/src/extension/inlineEdits/node/nextEditProvider.ts
index 0056c2c67800..cd651193fbc9 100644
--- a/extensions/copilot/src/extension/inlineEdits/node/nextEditProvider.ts
+++ b/extensions/copilot/src/extension/inlineEdits/node/nextEditProvider.ts
@@ -41,8 +41,6 @@ import { CachedOrRebasedEdit, NextEditCache } from './nextEditCache';
 import { LlmNESTelemetryBuilder } from './nextEditProviderTelemetry';
 import { INextEditResult, NextEditResult } from './nextEditResult';
 
-const ARTIFICIAL_CACHE_HIT_DELAY = 300; // delay cache hits by 300ms to make it more like a regular request and to reduce flicker ;)
-
 export interface INextEditProvider<T extends INextEditResult, TTelemetry, TData = void> extends IDisposable {
 	readonly ID: string;
 	getNextEdit(docId: DocumentId, context: vscode.InlineCompletionContext, logContext: InlineEditRequestLogContext, cancellationToken: CancellationToken, telemetryBuilder: TTelemetry, data?: TData): Promise<T>;
@@ -160,6 +158,8 @@ export class NextEditProvider extends Disposable implements INextEditProvider<Ne
 		let req: NextEditFetchRequest;
 		let targetDocumentId = docId;
 
+		const cacheDelay = this._configService.getExperimentBasedConfig(ConfigKey.Internal.InlineEditsCacheDelay, this._expService);
+
 		if (recentlyShownCachedEdit) {
 			tracer.trace('using recently shown cached edit');
 			edit = recentlyShownCachedEdit[0];
@@ -173,7 +173,7 @@ export class NextEditProvider extends Disposable implements INextEditProvider<Ne
 			// back-date the recording bookmark of the cached edit to the bookmark of the original request.
 			logContext.recordingBookmark = req.log.recordingBookmark;
 
-			await timeout(ARTIFICIAL_CACHE_HIT_DELAY);
+			await timeout(cacheDelay);
 
 		} else if (cachedEdit) {
 			tracer.trace('using cached edit');
@@ -187,7 +187,7 @@ export class NextEditProvider extends Disposable implements INextEditProvider<Ne
 			// back-date the recording bookmark of the cached edit to the bookmark of the original request.
 			logContext.recordingBookmark = req.log.recordingBookmark;
 
-			await timeout(ARTIFICIAL_CACHE_HIT_DELAY);
+			await timeout(cacheDelay);
 
 		} else {
 			tracer.trace('fetching next edit');
diff --git a/extensions/copilot/src/platform/configuration/common/configurationService.ts b/extensions/copilot/src/platform/configuration/common/configurationService.ts
index 2a577338154b..401de1b190ac 100644
--- a/extensions/copilot/src/platform/configuration/common/configurationService.ts
+++ b/extensions/copilot/src/platform/configuration/common/configurationService.ts
@@ -645,6 +645,7 @@ export namespace ConfigKey {
 		export const InlineEditsYieldToCopilot = defineExpSetting<boolean>('chat.advanced.inlineEdits.yieldToCopilot', false, INTERNAL_RESTRICTED);
 		export const InlineEditsLogContextRecorderEnabled = defineSetting('chat.advanced.inlineEdits.logContextRecorder.enabled', false, INTERNAL_RESTRICTED);
 		export const InlineEditsDebounce = defineExpSetting<number>('chat.advanced.inlineEdits.debounce', 200, INTERNAL_RESTRICTED);
+		export const InlineEditsCacheDelay = defineExpSetting<number>('chat.advanced.inlineEdits.cacheDelay', 300, INTERNAL_RESTRICTED);
 		export const InlineEditsBackoffDebounceEnabled = defineExpSetting<boolean>('chat.advanced.inlineEdits.backoffDebounceEnabled', true, INTERNAL_RESTRICTED);
 		export const InlineEditsExtraDebounceEndOfLine = defineExpSetting<number>('chat.advanced.inlineEdits.extraDebounceEndOfLine', 0, INTERNAL_RESTRICTED);
 		export const InlineEditsDebounceOnSelectionChange = defineExpSetting<number | undefined>('chat.advanced.inlineEdits.debounceOnSelectionChange', undefined, INTERNAL_RESTRICTED);