Removing deprecated code for the delays introduced for low perf langu…

…ages (#5957)

This PR removes the artificial latency logic and associated feature
flags that were previously added for A/B testing to improve the
consistency and predictability of the autocomplete latency.

Context:
The artificial latency was initially introduced as an optimization for
low-performance languages, but recent testing and analysis have shown
that the latency changes are minimal, and the feature is no longer
necessary. Additionally, the smart throttle service is now enabled by
default, rendering the artificial latency code obsolete.

Changes:
- Removed the artificial latency code from
vscode/src/completions/artificial-delay.ts.
- Cleaned up related feature flags from the codebase to simplify the
code and avoid confusion in the future.
- Updated related test cases and documentation to reflect these changes.

## Test plan
Tested locally and it works perfect and the tests pass

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## Changelog

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lib/shared/src/experimentation/FeatureFlagProvider.ts

@@ -46,7 +46,6 @@ export enum FeatureFlag {
     CodyAutocompleteFIMModelExperimentVariant2 = 'cody-autocomplete-model-v1-experiment-variant-2',
     CodyAutocompleteFIMModelExperimentVariant3 = 'cody-autocomplete-model-v1-experiment-variant-3',
     CodyAutocompleteFIMModelExperimentVariant4 = 'cody-autocomplete-model-v1-experiment-variant-4',
-    CodyAutocompleteDisableLowPerfLangDelay = 'cody-autocomplete-disable-low-perf-lang-delay',
 
     CodyAutocompletePreloadingExperimentBaseFeatureFlag = 'cody-autocomplete-preloading-experiment-flag',
     CodyAutocompletePreloadingExperimentVariant1 = 'cody-autocomplete-preloading-experiment-variant-1',

vscode/src/completions/analytics-logger.ts

@@ -167,9 +167,6 @@ interface SharedEventPayload extends InteractionIDPayload {
      */
     isFuzzyMatch?: boolean
 
-    /** Eventual artificial delay that was used to throttle unwanted completions. */
-    artificialDelay?: number
-
     /**
      * Mapping the completion intent to a higher level abstractions of syntax nodes (e.g. function
      * declaration body)

vscode/src/completions/completion-provider-config.ts

@@ -34,7 +34,6 @@ class CompletionProviderConfig {
             FeatureFlag.CodyAutocompletePreloadingExperimentBaseFeatureFlag,
             FeatureFlag.CodyAutocompletePreloadingExperimentVariant1,
             FeatureFlag.CodyAutocompletePreloadingExperimentVariant2,
-            FeatureFlag.CodyAutocompleteDisableLowPerfLangDelay,
             FeatureFlag.CodyAutocompleteDataCollectionFlag,
             FeatureFlag.CodyAutocompleteTracing,
             FeatureFlag.CodyAutocompleteFastPath,
@@ -183,12 +182,6 @@ class CompletionProviderConfig {
         )
     }
 
-    public get completionDisableLowPerfLangDelay(): Observable<boolean> {
-        return featureFlagProvider
-            .evaluatedFeatureFlag(FeatureFlag.CodyAutocompleteDisableLowPerfLangDelay)
-            .pipe(distinctUntilChanged())
-    }
-
     public get completionDataCollectionFlag(): Observable<boolean> {
         return featureFlagProvider
             .evaluatedFeatureFlag(FeatureFlag.CodyAutocompleteDataCollectionFlag)

vscode/src/completions/get-inline-completions-tests/analytics.test.ts

@@ -133,7 +133,6 @@ describe('[getInlineCompletions] completion event', () => {
                 ],
                 "loggedPartialAcceptedLength": 0,
                 "params": {
-                  "artificialDelay": undefined,
                   "completionIntent": "function.body",
                   "contextSummary": {
                     "prefixChars": 16,
@@ -205,7 +204,6 @@ describe('[getInlineCompletions] completion event', () => {
                 ],
                 "loggedPartialAcceptedLength": 0,
                 "params": {
-                  "artificialDelay": undefined,
                   "completionIntent": "return_statement",
                   "contextSummary": {
                     "prefixChars": 25,

vscode/src/completions/get-inline-completions.ts

@@ -62,7 +62,6 @@ export interface InlineCompletionsParams {
     abortSignal?: AbortSignal
     cancellationListener?: vscode.Disposable
     tracer?: (data: Partial<ProvideInlineCompletionsItemTraceData>) => void
-    artificialDelay?: number
     firstCompletionTimeout: number
     numberOfCompletionsToGenerate?: number
 
@@ -238,7 +237,6 @@ async function doGetInlineCompletions(
         tracer,
         handleDidAcceptCompletionItem,
         handleDidPartiallyAcceptCompletionItem,
-        artificialDelay,
         firstCompletionTimeout,
         completionIntent,
         lastAcceptedCompletionItem,
@@ -321,7 +319,6 @@ async function doGetInlineCompletions(
         languageId: document.languageId,
         testFile: isValidTestFile(document.uri),
         completionIntent,
-        artificialDelay,
         traceId: getActiveTraceAndSpanId()?.traceId,
         stageTimings: stageRecorder.stageTimings,
     })
@@ -422,8 +419,7 @@ async function doGetInlineCompletions(
         ? 0
         : triggerKind !== TriggerKind.Automatic
           ? 0
-          : ((multiline ? debounceInterval?.multiLine : debounceInterval?.singleLine) ?? 0) +
-            (artificialDelay ?? 0)
+          : (multiline ? debounceInterval?.multiLine : debounceInterval?.singleLine) ?? 0
 
     // We split the desired debounceTime into two chunks. One that is at most 25ms where every
     // further execution is halted...

vscode/src/completions/inline-completion-item-provider.ts

@@ -24,7 +24,6 @@ import { isInTutorial } from '../tutorial/helpers'
 
 import type { CompletionBookkeepingEvent, CompletionItemID, CompletionLogID } from './analytics-logger'
 import * as CompletionAnalyticsLogger from './analytics-logger'
-import { getArtificialDelay } from './artificial-delay'
 import { completionProviderConfig } from './completion-provider-config'
 import { ContextMixer } from './context/context-mixer'
 import { DefaultContextStrategyFactory } from './context/context-strategy'
@@ -129,8 +128,6 @@ export class InlineCompletionItemProvider
     public get config(): InlineCompletionItemProviderConfig {
         return InlineCompletionItemProviderConfigSingleton.configuration
     }
-    private disableLowPerfLangDelay = false
-
     constructor({
         completeSuggestWidgetSelection = true,
         triggerDelay = 0,
@@ -194,16 +191,6 @@ export class InlineCompletionItemProvider
 
         void completionProviderConfig.prefetch()
 
-        // Subscribe to changes in disableLowPerfLangDelay and update the value accordingly
-        this.disposables.push(
-            subscriptionDisposable(
-                completionProviderConfig.completionDisableLowPerfLangDelay.subscribe(
-                    disableLowPerfLangDelay => {
-                        this.disableLowPerfLangDelay = disableLowPerfLangDelay
-                    }
-                )
-            )
-        )
         const strategyFactory = new DefaultContextStrategyFactory(
             completionProviderConfig.contextStrategy
         )
@@ -458,12 +445,6 @@ export class InlineCompletionItemProvider
                 return null
             }
 
-            const artificialDelay = getArtificialDelay({
-                languageId: document.languageId,
-                codyAutocompleteDisableLowPerfLangDelay: this.disableLowPerfLangDelay,
-                completionIntent,
-            })
-
             const debounceInterval = this.config.provider.mayUseOnDeviceInference ? 125 : 75
             stageRecorder.record('preGetInlineCompletions')
 
@@ -495,7 +476,6 @@ export class InlineCompletionItemProvider
                     handleDidPartiallyAcceptCompletionItem:
                         this.unstable_handleDidPartiallyAcceptCompletionItem.bind(this),
                     completeSuggestWidgetSelection: takeSuggestWidgetSelectionIntoAccount,
-                    artificialDelay,
                     firstCompletionTimeout: this.config.firstCompletionTimeout,
                     completionIntent,
                     lastAcceptedCompletionItem: this.lastAcceptedCompletionItem,