chrome-devtools-frontend/front_end/core/sdk/DebuggerModel.ts

Chrome DevTools UI

// Copyright 2010 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import type * as ProtocolProxyApi from '../../generated/protocol-proxy-api.js';
import * as Protocol from '../../generated/protocol.js';
import * as Common from '../common/common.js';
import * as i18n from '../i18n/i18n.js';
import type * as Platform from '../platform/platform.js';
import * as Root from '../root/root.js';

import type {PageResourceLoadInitiator} from './PageResourceLoader.js';
import {type GetPropertiesResult, type RemoteObject, RemoteObjectProperty, ScopeRef} from './RemoteObject.js';
import {Events as ResourceTreeModelEvents, ResourceTreeModel} from './ResourceTreeModel.js';
import {type EvaluationOptions, type EvaluationResult, type ExecutionContext, RuntimeModel} from './RuntimeModel.js';
import {Script} from './Script.js';
import {SDKModel} from './SDKModel.js';
import {SourceMap} from './SourceMap.js';
import {SourceMapManager} from './SourceMapManager.js';
import {Capability, type Target} from './Target.js';

const UIStrings = {
  /**
   * @description Title of a section in the debugger showing local JavaScript variables.
   */
  local: 'Local',
  /**
   * @description Text that refers to closure as a programming term
   */
  closure: 'Closure',
  /**
   * @description Noun that represents a section or block of code in the Debugger Model. Shown in the Sources tab, while paused on a breakpoint.
   */
  block: 'Block',
  /**
   * @description Label for a group of JavaScript files
   */
  script: 'Script',
  /**
   * @description Title of a section in the debugger showing JavaScript variables from the a 'with'
   *block. Block here means section of code, 'with' refers to a JavaScript programming concept and
   *is a fixed term.
   */
  withBlock: '`With` block',
  /**
   * @description Title of a section in the debugger showing JavaScript variables from the a 'catch'
   *block. Block here means section of code, 'catch' refers to a JavaScript programming concept and
   *is a fixed term.
   */
  catchBlock: '`Catch` block',
  /**
   * @description Title of a section in the debugger showing JavaScript variables from the global scope.
   */
  global: 'Global',
  /**
   * @description Text for a JavaScript module, the programming concept
   */
  module: 'Module',
  /**
   * @description Text describing the expression scope in WebAssembly
   */
  expression: 'Expression',
  /**
   * @description Text in Scope Chain Sidebar Pane of the Sources panel
   */
  exception: 'Exception',
  /**
   * @description Text in Scope Chain Sidebar Pane of the Sources panel
   */
  returnValue: 'Return value',
} as const;
const str_ = i18n.i18n.registerUIStrings('core/sdk/DebuggerModel.ts', UIStrings);
const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);

export function sortAndMergeRanges(locationRanges: Protocol.Debugger.LocationRange[]):
    Protocol.Debugger.LocationRange[] {
  function compare(p1: Protocol.Debugger.ScriptPosition, p2: Protocol.Debugger.ScriptPosition): number {
    return (p1.lineNumber - p2.lineNumber) || (p1.columnNumber - p2.columnNumber);
  }
  function overlap(r1: Protocol.Debugger.LocationRange, r2: Protocol.Debugger.LocationRange): boolean {
    if (r1.scriptId !== r2.scriptId) {
      return false;
    }
    const n = compare(r1.start, r2.start);
    if (n < 0) {
      return compare(r1.end, r2.start) >= 0;
    }
    if (n > 0) {
      return compare(r1.start, r2.end) <= 0;
    }
    return true;
  }

  if (locationRanges.length === 0) {
    return [];
  }
  locationRanges.sort((r1, r2) => {
    if (r1.scriptId < r2.scriptId) {
      return -1;
    }
    if (r1.scriptId > r2.scriptId) {
      return 1;
    }
    return compare(r1.start, r2.start) || compare(r1.end, r2.end);
  });
  let prev = locationRanges[0];
  const merged = [];
  for (let i = 1; i < locationRanges.length; ++i) {
    const curr = locationRanges[i];
    if (overlap(prev, curr)) {
      if (compare(prev.end, curr.end) <= 0) {
        prev = {...prev, end: curr.end};
      }
    } else {
      merged.push(prev);
      prev = curr;
    }
  }
  merged.push(prev);
  return merged;
}

export const enum StepMode {
  STEP_INTO = 'StepInto',
  STEP_OUT = 'StepOut',
  STEP_OVER = 'StepOver',
}

export const WASM_SYMBOLS_PRIORITY = [
  Protocol.Debugger.DebugSymbolsType.ExternalDWARF,
  Protocol.Debugger.DebugSymbolsType.EmbeddedDWARF,
  Protocol.Debugger.DebugSymbolsType.SourceMap,
];

export class DebuggerModel extends SDKModel<EventTypes> {
  readonly agent: ProtocolProxyApi.DebuggerApi;
  #runtimeModel: RuntimeModel;
  readonly #sourceMapManager: SourceMapManager<Script>;
  #debuggerPausedDetails: DebuggerPausedDetails|null = null;
  readonly #scripts = new Map<string, Script>();
  readonly #scriptsBySourceURL = new Map<string, Script[]>();
  #discardableScripts: Script[] = [];
  continueToLocationCallback: ((arg0: DebuggerPausedDetails) => boolean)|null = null;
  #selectedCallFrame: CallFrame|null = null;
  #debuggerEnabled = false;
  #debuggerId: string|null = null;
  #skipAllPausesTimeout = 0;
  #beforePausedCallback: ((arg0: DebuggerPausedDetails, stepOver: Location|null) => Promise<boolean>)|null = null;
  #computeAutoStepRangesCallback: ((arg0: StepMode, arg1: CallFrame) => Promise<Array<{
                                     start: Location,
                                     end: Location,
                                   }>>)|null = null;
  #expandCallFramesCallback: ((arg0: CallFrame[]) => Promise<CallFrame[]>)|null = null;
  evaluateOnCallFrameCallback:
      ((arg0: CallFrame, arg1: EvaluationOptions) => Promise<EvaluationResult|null>)|null = null;
  #synchronizeBreakpointsCallback: ((script: Script) => Promise<void>)|null = null;
  // We need to be able to register listeners for individual breakpoints. As such, we dispatch
  // on breakpoint ids, which are not statically known. The event #payload will always be a `Location`.
  readonly #breakpointResolvedEventTarget = new Common.ObjectWrapper.ObjectWrapper<Record<string, Location>>();
  // When stepping over with autostepping enabled, the context denotes the function to which autostepping is restricted
  // to by way of its functionLocation (as per Debugger.CallFrame).
  #autoSteppingContext: Location|null = null;
  #isPausing = false;

  constructor(target: Target) {
    super(target);

    target.registerDebuggerDispatcher(new DebuggerDispatcher(this));
    this.agent = target.debuggerAgent();
    this.#runtimeModel = (target.model(RuntimeModel) as RuntimeModel);

    this.#sourceMapManager = new SourceMapManager(
        target,
        (compiledURL, sourceMappingURL, payload, script) =>
            new SourceMap(compiledURL, sourceMappingURL, payload, script));

    Common.Settings.Settings.instance()
        .moduleSetting('pause-on-exception-enabled')
        .addChangeListener(this.pauseOnExceptionStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('pause-on-caught-exception')
        .addChangeListener(this.pauseOnExceptionStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('pause-on-uncaught-exception')
        .addChangeListener(this.pauseOnExceptionStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('disable-async-stack-traces')
        .addChangeListener(this.asyncStackTracesStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('breakpoints-active')
        .addChangeListener(this.breakpointsActiveChanged, this);

    if (!target.suspended()) {
      void this.enableDebugger();
    }

    this.#sourceMapManager.setEnabled(
        Common.Settings.Settings.instance().moduleSetting('js-source-maps-enabled').get());
    Common.Settings.Settings.instance()
        .moduleSetting('js-source-maps-enabled')
        .addChangeListener(event => this.#sourceMapManager.setEnabled((event.data as boolean)));

    const resourceTreeModel = (target.model(ResourceTreeModel) as ResourceTreeModel);
    if (resourceTreeModel) {
      resourceTreeModel.addEventListener(ResourceTreeModelEvents.FrameNavigated, this.onFrameNavigated, this);
    }
  }

  static selectSymbolSource(debugSymbols: Protocol.Debugger.DebugSymbols[]|null): Protocol.Debugger.DebugSymbols|null {
    if (!debugSymbols || debugSymbols.length === 0) {
      return null;
    }

    // Provides backwards compatibility to previous CDP version on Protocol.Debugger.DebugSymbols.
    // TODO(crbug.com/369515221): Remove extra code as soon as old v8 versions used in Node are no longer supported.
    if ('type' in debugSymbols) {
      if (debugSymbols.type === 'None') {
        return null;
      }
      return debugSymbols as Protocol.Debugger.DebugSymbols;
    }

    let debugSymbolsSource = null;
    const symbolTypes = new Map(debugSymbols.map(symbol => [symbol.type, symbol]));
    for (const symbol of WASM_SYMBOLS_PRIORITY) {
      if (symbolTypes.has(symbol)) {
        debugSymbolsSource = symbolTypes.get(symbol) || null;
        break;
      }
    }

    console.assert(
        debugSymbolsSource !== null,
        'Unknown symbol types. Front-end and back-end should be kept in sync regarding Protocol.Debugger.DebugSymbolTypes');
    if (debugSymbolsSource && debugSymbols.length > 1) {
      Common.Console.Console.instance().warn(
          `Multiple debug symbols for script were found. Using ${debugSymbolsSource.type}`);
    }
    return debugSymbolsSource;
  }

  sourceMapManager(): SourceMapManager<Script> {
    return this.#sourceMapManager;
  }

  runtimeModel(): RuntimeModel {
    return this.#runtimeModel;
  }

  debuggerEnabled(): boolean {
    return Boolean(this.#debuggerEnabled);
  }

  debuggerId(): string|null {
    return this.#debuggerId;
  }

  private async enableDebugger(): Promise<void> {
    if (this.#debuggerEnabled) {
      return;
    }
    this.#debuggerEnabled = true;

    // Set a limit for the total size of collected script sources retained by debugger.
    // 10MB for remote frontends, 100MB for others.
    const isRemoteFrontend = Root.Runtime.Runtime.queryParam('remoteFrontend') || Root.Runtime.Runtime.queryParam('ws');
    const maxScriptsCacheSize = isRemoteFrontend ? 10e6 : 100e6;
    const enablePromise = this.agent.invoke_enable({maxScriptsCacheSize});
    let instrumentationPromise: Promise<Protocol.Debugger.SetInstrumentationBreakpointResponse>|undefined;
    if (Root.Runtime.experiments.isEnabled(Root.Runtime.ExperimentName.INSTRUMENTATION_BREAKPOINTS)) {
      instrumentationPromise = this.agent.invoke_setInstrumentationBreakpoint({
        instrumentation: Protocol.Debugger.SetInstrumentationBreakpointRequestInstrumentation.BeforeScriptExecution,
      });
    }
    this.pauseOnExceptionStateChanged();
    void this.asyncStackTracesStateChanged();
    if (!Common.Settings.Settings.instance().moduleSetting('breakpoints-active').get()) {
      this.breakpointsActiveChanged();
    }
    this.dispatchEventToListeners(Events.DebuggerWasEnabled, this);
    const [enableResult] = await Promise.all([enablePromise, instrumentationPromise]);
    this.registerDebugger(enableResult);
  }

  async syncDebuggerId(): Promise<Protocol.Debugger.EnableResponse> {
    const isRemoteFrontend = Root.Runtime.Runtime.queryParam('remoteFrontend') || Root.Runtime.Runtime.queryParam('ws');
    const maxScriptsCacheSize = isRemoteFrontend ? 10e6 : 100e6;
    const enablePromise = this.agent.invoke_enable({maxScriptsCacheSize});
    void enablePromise.then(this.registerDebugger.bind(this));
    return await enablePromise;
  }

  private onFrameNavigated(): void {
    if (DebuggerModel.shouldResyncDebuggerId) {
      return;
    }

    DebuggerModel.shouldResyncDebuggerId = true;
  }

  private registerDebugger(response: Protocol.Debugger.EnableResponse): void {
    if (response.getError()) {
      this.#debuggerEnabled = false;
      return;
    }
    const {debuggerId} = response;
    debuggerIdToModel.set(debuggerId, this);
    this.#debuggerId = debuggerId;
    this.dispatchEventToListeners(Events.DebuggerIsReadyToPause, this);
  }

  isReadyToPause(): boolean {
    return Boolean(this.#debuggerId);
  }

  static async modelForDebuggerId(debuggerId: string): Promise<DebuggerModel|null> {
    if (DebuggerModel.shouldResyncDebuggerId) {
      await DebuggerModel.resyncDebuggerIdForModels();
      DebuggerModel.shouldResyncDebuggerId = false;
    }
    return debuggerIdToModel.get(debuggerId) || null;
  }

  static async resyncDebuggerIdForModels(): Promise<void> {
    const dbgModels = debuggerIdToModel.values();
    for (const dbgModel of dbgModels) {
      if (dbgModel.debuggerEnabled()) {
        await dbgModel.syncDebuggerId();
      }
    }
  }

  private async disableDebugger(): Promise<void> {
    if (!this.#debuggerEnabled) {
      return;
    }
    this.#debuggerEnabled = false;

    await this.asyncStackTracesStateChanged();
    await this.agent.invoke_disable();
    this.#isPausing = false;
    this.globalObjectCleared();
    this.dispatchEventToListeners(Events.DebuggerWasDisabled, this);
    if (typeof this.#debuggerId === 'string') {
      debuggerIdToModel.delete(this.#debuggerId);
    }
    this.#debuggerId = null;
  }

  private skipAllPauses(skip: boolean): void {
    if (this.#skipAllPausesTimeout) {
      clearTimeout(this.#skipAllPausesTimeout);
      this.#skipAllPausesTimeout = 0;
    }
    void this.agent.invoke_setSkipAllPauses({skip});
  }

  skipAllPausesUntilReloadOrTimeout(timeout: number): void {
    if (this.#skipAllPausesTimeout) {
      clearTimeout(this.#skipAllPausesTimeout);
    }
    void this.agent.invoke_setSkipAllPauses({skip: true});
    // If reload happens before the timeout, the flag will be already unset and the timeout callback won't change anything.
    this.#skipAllPausesTimeout = window.setTimeout(this.skipAllPauses.bind(this, false), timeout);
  }

  private pauseOnExceptionStateChanged(): void {
    const pauseOnCaughtEnabled = Common.Settings.Settings.instance().moduleSetting('pause-on-caught-exception').get();
    let state: Protocol.Debugger.SetPauseOnExceptionsRequestState;

    const pauseOnUncaughtEnabled =
        Common.Settings.Settings.instance().moduleSetting('pause-on-uncaught-exception').get();
    if (pauseOnCaughtEnabled && pauseOnUncaughtEnabled) {
      state = Protocol.Debugger.SetPauseOnExceptionsRequestState.All;
    } else if (pauseOnCaughtEnabled) {
      state = Protocol.Debugger.SetPauseOnExceptionsRequestState.Caught;
    } else if (pauseOnUncaughtEnabled) {
      state = Protocol.Debugger.SetPauseOnExceptionsRequestState.Uncaught;
    } else {
      state = Protocol.Debugger.SetPauseOnExceptionsRequestState.None;
    }
    void this.agent.invoke_setPauseOnExceptions({state});
  }

  private asyncStackTracesStateChanged(): Promise<Protocol.ProtocolResponseWithError> {
    const maxAsyncStackChainDepth = 32;
    const enabled =
        !Common.Settings.Settings.instance().moduleSetting('disable-async-stack-traces').get() && this.#debuggerEnabled;
    const maxDepth = enabled ? maxAsyncStackChainDepth : 0;
    return this.agent.invoke_setAsyncCallStackDepth({maxDepth});
  }

  private breakpointsActiveChanged(): void {
    void this.agent.invoke_setBreakpointsActive(
        {active: Common.Settings.Settings.instance().moduleSetting('breakpoints-active').get()});
  }

  setComputeAutoStepRangesCallback(callback: ((arg0: StepMode, arg1: CallFrame) => Promise<LocationRange[]>)|null):
      void {
    this.#computeAutoStepRangesCallback = callback;
  }

  private async computeAutoStepSkipList(mode: StepMode): Promise<Protocol.Debugger.LocationRange[]> {
    let ranges: LocationRange[] = [];
    if (this.#computeAutoStepRangesCallback && this.#debuggerPausedDetails &&
        this.#debuggerPausedDetails.callFrames.length > 0) {
      const [callFrame] = this.#debuggerPausedDetails.callFrames;
      ranges = await this.#computeAutoStepRangesCallback.call(null, mode, callFrame);
    }
    const skipList = ranges.map(({start, end}) => ({
                                  scriptId: start.scriptId,
                                  start: {lineNumber: start.lineNumber, columnNumber: start.columnNumber},
                                  end: {lineNumber: end.lineNumber, columnNumber: end.columnNumber},
                                }));
    return sortAndMergeRanges(skipList);
  }

  async stepInto(): Promise<void> {
    const skipList = await this.computeAutoStepSkipList(StepMode.STEP_INTO);
    void this.agent.invoke_stepInto({breakOnAsyncCall: false, skipList});
  }

  async stepOver(): Promise<void> {
    this.#autoSteppingContext = this.#debuggerPausedDetails?.callFrames[0]?.functionLocation() ?? null;
    const skipList = await this.computeAutoStepSkipList(StepMode.STEP_OVER);
    void this.agent.invoke_stepOver({skipList});
  }

  async stepOut(): Promise<void> {
    const skipList = await this.computeAutoStepSkipList(StepMode.STEP_OUT);
    if (skipList.length !== 0) {
      void this.agent.invoke_stepOver({skipList});
    } else {
      void this.agent.invoke_stepOut();
    }
  }

  scheduleStepIntoAsync(): void {
    void this.computeAutoStepSkipList(StepMode.STEP_INTO).then(skipList => {
      void this.agent.invoke_stepInto({breakOnAsyncCall: true, skipList});
    });
  }

  resume(): void {
    void this.agent.invoke_resume({terminateOnResume: false});
    this.#isPausing = false;
  }

  pause(): void {
    this.#isPausing = true;
    this.skipAllPauses(false);
    void this.agent.invoke_pause();
  }

  async setBreakpointByURL(
      url: Platform.DevToolsPath.UrlString, lineNumber: number, columnNumber?: number,
      condition?: BackendCondition): Promise<SetBreakpointResult> {
    // Adjust column if needed.
    let minColumnNumber = 0;
    const scripts = this.#scriptsBySourceURL.get(url) || [];
    for (let i = 0, l = scripts.length; i < l; ++i) {
      const script = scripts[i];
      if (lineNumber === script.lineOffset) {
        minColumnNumber = minColumnNumber ? Math.min(minColumnNumber, script.columnOffset) : script.columnOffset;
      }
    }
    columnNumber = Math.max(columnNumber || 0, minColumnNumber);
    const response = await this.agent.invoke_setBreakpointByUrl({
      lineNumber,
      url,
      columnNumber,
      condition,
    });
    if (response.getError()) {
      return {locations: [], breakpointId: null};
    }
    let locations: Location[] = [];
    if (response.locations) {
      locations = response.locations.map(payload => Location.fromPayload(this, payload));
    }
    return {locations, breakpointId: response.breakpointId};
  }

  async setBreakpointInAnonymousScript(
      scriptHash: string, lineNumber: number, columnNumber?: number,
      condition?: BackendCondition): Promise<SetBreakpointResult> {
    const response = await this.agent.invoke_setBreakpointByUrl({lineNumber, scriptHash, columnNumber, condition});
    if (response.getError()) {
      return {locations: [], breakpointId: null};
    }
    let locations: Location[] = [];
    if (response.locations) {
      locations = response.locations.map(payload => Location.fromPayload(this, payload));
    }
    return {locations, breakpointId: response.breakpointId};
  }

  async removeBreakpoint(breakpointId: Protocol.Debugger.BreakpointId): Promise<void> {
    await this.agent.invoke_removeBreakpoint({breakpointId});
  }

  async getPossibleBreakpoints(startLocation: Location, endLocation: Location|null, restrictToFunction: boolean):
      Promise<BreakLocation[]> {
    const response = await this.agent.invoke_getPossibleBreakpoints({
      start: startLocation.payload(),
      end: endLocation ? endLocation.payload() : undefined,
      restrictToFunction,
    });
    if (response.getError() || !response.locations) {
      return [];
    }
    return response.locations.map(location => BreakLocation.fromPayload(this, location));
  }

  async fetchAsyncStackTrace(stackId: Protocol.Runtime.StackTraceId): Promise<Protocol.Runtime.StackTrace|null> {
    const response = await this.agent.invoke_getStackTrace({stackTraceId: stackId});
    return response.getError() ? null : response.stackTrace;
  }

  breakpointResolved(breakpointId: string, location: Protocol.Debugger.Location): void {
    this.#breakpointResolvedEventTarget.dispatchEventToListeners(breakpointId, Location.fromPayload(this, location));
  }

  globalObjectCleared(): void {
    this.resetDebuggerPausedDetails();
    this.reset();
    // TODO(dgozman): move clients to ExecutionContextDestroyed/ScriptCollected events.
    this.dispatchEventToListeners(Events.GlobalObjectCleared, this);
  }

  private reset(): void {
    for (const script of this.#scripts.values()) {
      this.#sourceMapManager.detachSourceMap(script);
    }
    this.#scripts.clear();
    this.#scriptsBySourceURL.clear();
    this.#discardableScripts = [];
    this.#autoSteppingContext = null;
  }

  scripts(): Script[] {
    return Array.from(this.#scripts.values());
  }

  scriptForId(scriptId: string): Script|null {
    return this.#scripts.get(scriptId) || null;
  }

  /**
   * Returns all `Script` objects with the same provided `sourceURL`. The
   * resulting array is sorted by time with the newest `Script` in the front.
   */
  scriptsForSourceURL(sourceURL: string): Script[] {
    return this.#scriptsBySourceURL.get(sourceURL) || [];
  }

  scriptsForExecutionContext(executionContext: ExecutionContext): Script[] {
    const result = [];
    for (const script of this.#scripts.values()) {
      if (script.executionContextId === executionContext.id) {
        result.push(script);
      }
    }
    return result;
  }

  get callFrames(): CallFrame[]|null {
    return this.#debuggerPausedDetails ? this.#debuggerPausedDetails.callFrames : null;
  }

  debuggerPausedDetails(): DebuggerPausedDetails|null {
    return this.#debuggerPausedDetails;
  }

  private async setDebuggerPausedDetails(debuggerPausedDetails: DebuggerPausedDetails): Promise<boolean> {
    this.#isPausing = false;
    this.#debuggerPausedDetails = debuggerPausedDetails;
    if (this.#beforePausedCallback) {
      if (!await this.#beforePausedCallback.call(null, debuggerPausedDetails, this.#autoSteppingContext)) {
        return false;
      }
    }
    // If we resolved a location in auto-stepping callback, reset the
    // auto-step-over context.
    this.#autoSteppingContext = null;
    this.dispatchEventToListeners(Events.DebuggerPaused, this);
    this.setSelectedCallFrame(debuggerPausedDetails.callFrames[0]);
    return true;
  }

  private resetDebuggerPausedDetails(): void {
    this.#isPausing = false;
    this.#debuggerPausedDetails = null;
    this.setSelectedCallFrame(null);
  }

  setBeforePausedCallback(
      callback: ((arg0: DebuggerPausedDetails, autoSteppingContext: Location|null) => Promise<boolean>)|null): void {
    this.#beforePausedCallback = callback;
  }

  setExpandCallFramesCallback(callback: ((arg0: CallFrame[]) => Promise<CallFrame[]>)|null): void {
    this.#expandCallFramesCallback = callback;
  }

  setEvaluateOnCallFrameCallback(
      callback: ((arg0: CallFrame, arg1: EvaluationOptions) => Promise<EvaluationResult|null>)|null): void {
    this.evaluateOnCallFrameCallback = callback;
  }

  setSynchronizeBreakpointsCallback(callback: ((script: Script) => Promise<void>)|null): void {
    this.#synchronizeBreakpointsCallback = callback;
  }

  async pausedScript(
      callFrames: Protocol.Debugger.CallFrame[], reason: Protocol.Debugger.PausedEventReason, auxData: Object|undefined,
      breakpointIds: string[], asyncStackTrace?: Protocol.Runtime.StackTrace,
      asyncStackTraceId?: Protocol.Runtime.StackTraceId): Promise<void> {
    if (reason === Protocol.Debugger.PausedEventReason.Instrumentation) {
      const script = this.scriptForId((auxData as PausedOnInstrumentationData).scriptId);
      if (this.#synchronizeBreakpointsCallback && script) {
        await this.#synchronizeBreakpointsCallback(script);
      }
      this.resume();
      return;
    }

    const pausedDetails =
        new DebuggerPausedDetails(this, callFrames, reason, auxData, breakpointIds, asyncStackTrace, asyncStackTraceId);
    await this.#expandCallFrames(pausedDetails);

    if (this.continueToLocationCallback) {
      const callback = this.continueToLocationCallback;
      this.continueToLocationCallback = null;
      if (callback(pausedDetails)) {
        return;
      }
    }

    if (!await this.setDebuggerPausedDetails(pausedDetails)) {
      if (this.#autoSteppingContext) {
        void this.stepOver();
      } else {
        void this.stepInto();
      }
    } else {
      Common.EventTarget.fireEvent('DevTools.DebuggerPaused');
    }
  }

  /** Delegates to the DebuggerLanguagePlugin and potential attached source maps to expand inlined call frames */
  async #expandCallFrames(pausedDetails: DebuggerPausedDetails): Promise<void> {
    if (this.#expandCallFramesCallback) {
      pausedDetails.callFrames = await this.#expandCallFramesCallback.call(null, pausedDetails.callFrames);
    }

    if (!Root.Runtime.experiments.isEnabled(Root.Runtime.ExperimentName.USE_SOURCE_MAP_SCOPES)) {
      return;
    }

    // TODO(crbug.com/40277685): Support attaching/detaching source maps after pausing.
    // Expanding call frames via source maps here is only suitable for the experiment prototype because
    // we block until all relevant source maps are loaded.
    // We should change this so the "Debugger Plugin" and "Source Map" have a bottle neck where they expand
    // call frames and that bottleneck should support attaching/detaching source maps while paused.
    const finalFrames: CallFrame[] = [];
    for (const frame of pausedDetails.callFrames) {
      const sourceMap = await this.sourceMapManager().sourceMapForClientPromise(frame.script);
      if (sourceMap?.hasScopeInfo()) {
        finalFrames.push(...sourceMap.expandCallFrame(frame));
      } else {
        finalFrames.push(frame);
      }
    }
    pausedDetails.callFrames = finalFrames;
  }

  resumedScript(): void {
    this.resetDebuggerPausedDetails();
    this.dispatchEventToListeners(Events.DebuggerResumed, this);
  }

  parsedScriptSource(
      scriptId: Protocol.Runtime.ScriptId, sourceURL: Platform.DevToolsPath.UrlString, startLine: number,
      startColumn: number, endLine: number, endColumn: number,
      // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      executionContextId: number, hash: string, executionContextAuxData: any, isLiveEdit: boolean,
      sourceMapURL: string|undefined, hasSourceURLComment: boolean, hasSyntaxError: boolean, length: number,
      isModule: boolean|null, originStackTrace: Protocol.Runtime.StackTrace|null, codeOffset: number|null,
      scriptLanguage: string|null, debugSymbols: Protocol.Debugger.DebugSymbols[]|null,
      embedderName: Platform.DevToolsPath.UrlString|null, buildId: string|null): Script {
    const knownScript = this.#scripts.get(scriptId);
    if (knownScript) {
      return knownScript;
    }
    let isContentScript = false;
    if (executionContextAuxData && ('isDefault' in executionContextAuxData)) {
      isContentScript = !executionContextAuxData['isDefault'];
    }

    const selectedDebugSymbol = DebuggerModel.selectSymbolSource(debugSymbols);
    const script = new Script(
        this, scriptId, sourceURL, startLine, startColumn, endLine, endColumn, executionContextId, hash,
        isContentScript, isLiveEdit, sourceMapURL, hasSourceURLComment, length, isModule, originStackTrace, codeOffset,
        scriptLanguage, selectedDebugSymbol, embedderName, buildId);
    this.registerScript(script);
    this.dispatchEventToListeners(Events.ParsedScriptSource, script);

    if (script.sourceMapURL && !hasSyntaxError) {
      this.#sourceMapManager.attachSourceMap(script, script.sourceURL, script.sourceMapURL);
    }

    const isDiscardable = hasSyntaxError && script.isAnonymousScript();
    if (isDiscardable) {
      this.#discardableScripts.push(script);
      this.collectDiscardedScripts();
    }
    return script;
  }

  setSourceMapURL(script: Script, newSourceMapURL: Platform.DevToolsPath.UrlString): void {
    // Detach any previous source map from the `script` first.
    this.#sourceMapManager.detachSourceMap(script);
    script.sourceMapURL = newSourceMapURL;
    this.#sourceMapManager.attachSourceMap(script, script.sourceURL, script.sourceMapURL);
  }

  async setDebugInfoURL(script: Script, _externalURL: Platform.DevToolsPath.UrlString): Promise<void> {
    if (this.#expandCallFramesCallback && this.#debuggerPausedDetails) {
      this.#debuggerPausedDetails.callFrames =
          await this.#expandCallFramesCallback.call(null, this.#debuggerPausedDetails.callFrames);
    }
    this.dispatchEventToListeners(Events.DebugInfoAttached, script);
  }

  executionContextDestroyed(executionContext: ExecutionContext): void {
    for (const script of this.#scripts.values()) {
      if (script.executionContextId === executionContext.id) {
        this.#sourceMapManager.detachSourceMap(script);
      }
    }
  }

  private registerScript(script: Script): void {
    this.#scripts.set(script.scriptId, script);
    if (script.isAnonymousScript()) {
      return;
    }

    let scripts = this.#scriptsBySourceURL.get(script.sourceURL);
    if (!scripts) {
      scripts = [];
      this.#scriptsBySourceURL.set(script.sourceURL, scripts);
    }
    // Newer scripts with the same URL should be preferred so we put them in
    // the front. Consuming code usually will iterate over the array and pick
    // the first script that works.
    scripts.unshift(script);
  }

  private unregisterScript(script: Script): void {
    console.assert(script.isAnonymousScript());
    this.#scripts.delete(script.scriptId);
  }

  private collectDiscardedScripts(): void {
    if (this.#discardableScripts.length < 1000) {
      return;
    }
    const scriptsToDiscard = this.#discardableScripts.splice(0, 100);
    for (const script of scriptsToDiscard) {
      this.unregisterScript(script);
      this.dispatchEventToListeners(Events.DiscardedAnonymousScriptSource, script);
    }
  }

  createRawLocation(script: Script, lineNumber: number, columnNumber: number, inlineFrameIndex?: number): Location {
    return this.createRawLocationByScriptId(script.scriptId, lineNumber, columnNumber, inlineFrameIndex);
  }

  createRawLocationByURL(sourceURL: string, lineNumber: number, columnNumber?: number, inlineFrameIndex?: number):
      Location|null {
    for (const script of this.#scriptsBySourceURL.get(sourceURL) || []) {
      if (script.lineOffset > lineNumber ||
          (script.lineOffset === lineNumber && columnNumber !== undefined && script.columnOffset > columnNumber)) {
        continue;
      }
      if (script.endLine < lineNumber ||
          (script.endLine === lineNumber && columnNumber !== undefined && script.endColumn <= columnNumber)) {
        continue;
      }
      return new Location(this, script.scriptId, lineNumber, columnNumber, inlineFrameIndex);
    }
    return null;
  }

  createRawLocationByScriptId(
      scriptId: Protocol.Runtime.ScriptId, lineNumber: number, columnNumber?: number,
      inlineFrameIndex?: number): Location {
    return new Location(this, scriptId, lineNumber, columnNumber, inlineFrameIndex);
  }

  createRawLocationsByStackTrace(stackTrace: Protocol.Runtime.StackTrace): Location[] {
    const rawLocations: Location[] = [];
    for (let current: Protocol.Runtime.StackTrace|undefined = stackTrace; current; current = current.parent) {
      for (const {scriptId, lineNumber, columnNumber} of current.callFrames) {
        rawLocations.push(this.createRawLocationByScriptId(scriptId, lineNumber, columnNumber));
      }
    }
    return rawLocations;
  }

  isPaused(): boolean {
    return Boolean(this.debuggerPausedDetails());
  }

  isPausing(): boolean {
    return this.#isPausing;
  }

  setSelectedCallFrame(callFrame: CallFrame|null): void {
    if (this.#selectedCallFrame === callFrame) {
      return;
    }
    this.#selectedCallFrame = callFrame;
    this.dispatchEventToListeners(Events.CallFrameSelected, this);
  }

  selectedCallFrame(): CallFrame|null {
    return this.#selectedCallFrame;
  }

  async evaluateOnSelectedCallFrame(options: EvaluationOptions): Promise<EvaluationResult> {
    const callFrame = this.selectedCallFrame();
    if (!callFrame) {
      throw new Error('No call frame selected');
    }
    return await callFrame.evaluate(options);
  }

  functionDetailsPromise(remoteObject: RemoteObject): Promise<FunctionDetails|null> {
    return remoteObject.getAllProperties(false /* accessorPropertiesOnly */, false /* generatePreview */)
        .then(buildDetails.bind(this));

    function buildDetails(this: DebuggerModel, response: GetPropertiesResult): FunctionDetails|null {
      if (!response) {
        return null;
      }
      let location: (RemoteObject|null|undefined)|null = null;
      if (response.internalProperties) {
        for (const prop of response.internalProperties) {
          if (prop.name === '[[FunctionLocation]]') {
            location = prop.value;
          }
        }
      }
      let functionName: RemoteObject|null = null;
      if (response.properties) {
        for (const prop of response.properties) {
          if (prop.name === 'name' && prop.value?.type === 'string') {
            functionName = prop.value;
          }
        }
      }
      let debuggerLocation: Location|null = null;
      if (location) {
        debuggerLocation = this.createRawLocationByScriptId(
            location.value.scriptId, location.value.lineNumber, location.value.columnNumber);
      }
      return {location: debuggerLocation, functionName: functionName ? functionName.value as string : ''};
    }
  }

  async setVariableValue(
      scopeNumber: number, variableName: string, newValue: Protocol.Runtime.CallArgument,
      callFrameId: Protocol.Debugger.CallFrameId): Promise<string|undefined> {
    const response = await this.agent.invoke_setVariableValue({scopeNumber, variableName, newValue, callFrameId});
    const error = response.getError();
    return error;
  }

  addBreakpointListener(
      breakpointId: string, listener: (arg0: Common.EventTarget.EventTargetEvent<Location>) => void,
      thisObject?: Object): void {
    this.#breakpointResolvedEventTarget.addEventListener(breakpointId, listener, thisObject);
  }

  removeBreakpointListener(
      breakpointId: string, listener: (arg0: Common.EventTarget.EventTargetEvent<Location>) => void,
      thisObject?: Object): void {
    this.#breakpointResolvedEventTarget.removeEventListener(breakpointId, listener, thisObject);
  }

  async setBlackboxPatterns(patterns: string[], skipAnonymous: boolean): Promise<boolean> {
    const response = await this.agent.invoke_setBlackboxPatterns({patterns, skipAnonymous});
    const error = response.getError();
    return !error;
  }

  async setBlackboxExecutionContexts(uniqueIds: string[]): Promise<boolean> {
    const response = await this.agent.invoke_setBlackboxExecutionContexts({uniqueIds});
    const error = response.getError();
    return !error;
  }

  override dispose(): void {
    if (this.#debuggerId) {
      debuggerIdToModel.delete(this.#debuggerId);
    }
    Common.Settings.Settings.instance()
        .moduleSetting('pause-on-exception-enabled')
        .removeChangeListener(this.pauseOnExceptionStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('pause-on-caught-exception')
        .removeChangeListener(this.pauseOnExceptionStateChanged, this);
    Common.Settings.Settings.instance()
        .moduleSetting('disable-async-stack-traces')
        .removeChangeListener(this.asyncStackTracesStateChanged, this);
  }

  override async suspendModel(): Promise<void> {
    await this.disableDebugger();
  }

  override async resumeModel(): Promise<void> {
    await this.enableDebugger();
  }

  private static shouldResyncDebuggerId = false;

  getEvaluateOnCallFrameCallback():
      ((arg0: CallFrame, arg1: EvaluationOptions) => Promise<EvaluationResult|null>)|null {
    return this.evaluateOnCallFrameCallback;
  }

  /**
   * Iterates the async stack trace parents.
   *
   * Retrieving cross-target async stack fragments requires CDP interaction, so this is an async generator.
   *
   * Important: This iterator will not yield the "synchronous" part of the stack trace, only the async parent chain.
   */
  async *
      iterateAsyncParents(
          stackTraceOrPausedDetails: Protocol.Runtime.StackTrace|
          Pick<DebuggerPausedDetails, 'asyncStackTrace'|'asyncStackTraceId'>):
          AsyncGenerator<{stackTrace: Protocol.Runtime.StackTrace, target: Target}> {
    // We make `DebuggerPausedDetails` look like a stack trace. We are only interested in `parent` and `parentId` in any case.
    const isPausedDetails = (details: typeof stackTraceOrPausedDetails):
        details is Pick<DebuggerPausedDetails, 'asyncStackTrace'|'asyncStackTraceId'> =>
            !('parent' in details) && !('parentId' in details);
    let stackTrace: Protocol.Runtime.StackTrace = isPausedDetails(stackTraceOrPausedDetails) ?
        {
          callFrames: [],
          parent: stackTraceOrPausedDetails.asyncStackTrace,
          parentId: stackTraceOrPausedDetails.asyncStackTraceId
        } :
        stackTraceOrPausedDetails;
    let target = this.target();

    while (true) {
      if (stackTrace.parent) {
        stackTrace = stackTrace.parent;
      } else if (stackTrace.parentId) {
        const model: DebuggerModel|null = stackTrace.parentId.debuggerId ?
            await DebuggerModel.modelForDebuggerId(stackTrace.parentId.debuggerId) :
            this;
        if (!model) {
          return;
        }
        const maybeStackTrace = await model.fetchAsyncStackTrace(stackTrace.parentId);
        if (!maybeStackTrace) {
          return;
        }
        stackTrace = maybeStackTrace;
        target = model.target();
      } else {
        return;
      }

      yield {stackTrace, target};
    }
  }
}

const debuggerIdToModel = new Map<string, DebuggerModel>();

/**
 * Keep these in sync with WebCore::V8Debugger
 */
export enum PauseOnExceptionsState {
  /* eslint-disable @typescript-eslint/naming-convention -- Used by web_tests. */
  DontPauseOnExceptions = 'none',
  PauseOnAllExceptions = 'all',
  PauseOnCaughtExceptions = 'caught',
  PauseOnUncaughtExceptions = 'uncaught',
  /* eslint-enable @typescript-eslint/naming-convention */
}

export enum Events {
  /* eslint-disable @typescript-eslint/naming-convention -- Used by web_tests. */
  DebuggerWasEnabled = 'DebuggerWasEnabled',
  DebuggerWasDisabled = 'DebuggerWasDisabled',
  DebuggerPaused = 'DebuggerPaused',
  DebuggerResumed = 'DebuggerResumed',
  DebugInfoAttached = 'DebugInfoAttached',
  ParsedScriptSource = 'ParsedScriptSource',
  DiscardedAnonymousScriptSource = 'DiscardedAnonymousScriptSource',
  GlobalObjectCleared = 'GlobalObjectCleared',
  CallFrameSelected = 'CallFrameSelected',
  DebuggerIsReadyToPause = 'DebuggerIsReadyToPause',
  ScriptSourceWasEdited = 'ScriptSourceWasEdited',
  /* eslint-enable @typescript-eslint/naming-convention */
}

export interface EventTypes {
  [Events.DebuggerWasEnabled]: DebuggerModel;
  [Events.DebuggerWasDisabled]: DebuggerModel;
  [Events.DebuggerPaused]: DebuggerModel;
  [Events.DebuggerResumed]: DebuggerModel;
  [Events.ParsedScriptSource]: Script;
  [Events.DiscardedAnonymousScriptSource]: Script;
  [Events.GlobalObjectCleared]: DebuggerModel;
  [Events.CallFrameSelected]: DebuggerModel;
  [Events.DebuggerIsReadyToPause]: DebuggerModel;
  [Events.DebugInfoAttached]: Script;
  [Events.ScriptSourceWasEdited]: {
    script: Script,
    status: Protocol.Debugger.SetScriptSourceResponseStatus,
  };
}

class DebuggerDispatcher implements ProtocolProxyApi.DebuggerDispatcher {
  #debuggerModel: DebuggerModel;

  constructor(debuggerModel: DebuggerModel) {
    this.#debuggerModel = debuggerModel;
  }

  paused({callFrames, reason, data, hitBreakpoints, asyncStackTrace, asyncStackTraceId}: Protocol.Debugger.PausedEvent):
      void {
    if (!this.#debuggerModel.debuggerEnabled()) {
      return;
    }
    void this.#debuggerModel.pausedScript(
        callFrames, reason, data, hitBreakpoints || [], asyncStackTrace, asyncStackTraceId);
  }

  resumed(): void {
    if (!this.#debuggerModel.debuggerEnabled()) {
      return;
    }
    this.#debuggerModel.resumedScript();
  }

  scriptParsed({
    scriptId,
    url,
    startLine,
    startColumn,
    endLine,
    endColumn,
    executionContextId,
    hash,
    executionContextAuxData,
    isLiveEdit,
    sourceMapURL,
    hasSourceURL,
    length,
    isModule,
    stackTrace,
    codeOffset,
    scriptLanguage,
    debugSymbols,
    embedderName,
    buildId,
  }: Protocol.Debugger.ScriptParsedEvent): void {
    if (!this.#debuggerModel.debuggerEnabled()) {
      return;
    }
    this.#debuggerModel.parsedScriptSource(
        scriptId, url as Platform.DevToolsPath.UrlString, startLine, startColumn, endLine, endColumn,
        executionContextId, hash, executionContextAuxData, Boolean(isLiveEdit), sourceMapURL, Boolean(hasSourceURL),
        false, length || 0, isModule || null, stackTrace || null, codeOffset || null, scriptLanguage || null,
        debugSymbols || null, embedderName as Platform.DevToolsPath.UrlString || null, buildId || null);
  }

  scriptFailedToParse({
    scriptId,
    url,
    startLine,
    startColumn,
    endLine,
    endColumn,
    executionContextId,
    hash,
    executionContextAuxData,
    sourceMapURL,
    hasSourceURL,
    length,
    isModule,
    stackTrace,
    codeOffset,
    scriptLanguage,
    embedderName,
    buildId,
  }: Protocol.Debugger.ScriptFailedToParseEvent): void {
    if (!this.#debuggerModel.debuggerEnabled()) {
      return;
    }
    this.#debuggerModel.parsedScriptSource(
        scriptId, url as Platform.DevToolsPath.UrlString, startLine, startColumn, endLine, endColumn,
        executionContextId, hash, executionContextAuxData, false, sourceMapURL, Boolean(hasSourceURL), true,
        length || 0, isModule || null, stackTrace || null, codeOffset || null, scriptLanguage || null, null,
        embedderName as Platform.DevToolsPath.UrlString || null, buildId || null);
  }

  breakpointResolved({breakpointId, location}: Protocol.Debugger.BreakpointResolvedEvent): void {
    if (!this.#debuggerModel.debuggerEnabled()) {
      return;
    }
    this.#debuggerModel.breakpointResolved(breakpointId, location);
  }
}

export class Location {
  debuggerModel: DebuggerModel;
  scriptId: Protocol.Runtime.ScriptId;
  lineNumber: number;
  columnNumber: number;
  inlineFrameIndex: number;

  constructor(
      debuggerModel: DebuggerModel, scriptId: Protocol.Runtime.ScriptId, lineNumber: number, columnNumber?: number,
      inlineFrameIndex?: number) {
    this.debuggerModel = debuggerModel;
    this.scriptId = scriptId;
    this.lineNumber = lineNumber;
    this.columnNumber = columnNumber || 0;
    this.inlineFrameIndex = inlineFrameIndex || 0;
  }

  static fromPayload(debuggerModel: DebuggerModel, payload: Protocol.Debugger.Location, inlineFrameIndex?: number):
      Location {
    return new Location(debuggerModel, payload.scriptId, payload.lineNumber, payload.columnNumber, inlineFrameIndex);
  }

  payload(): Protocol.Debugger.Location {
    return {scriptId: this.scriptId, lineNumber: this.lineNumber, columnNumber: this.columnNumber};
  }

  script(): Script|null {
    return this.debuggerModel.scriptForId(this.scriptId);
  }

  continueToLocation(pausedCallback?: (() => void)): void {
    if (pausedCallback) {
      this.debuggerModel.continueToLocationCallback = this.paused.bind(this, pausedCallback);
    }
    void this.debuggerModel.agent.invoke_continueToLocation({
      location: this.payload(),
      targetCallFrames: Protocol.Debugger.ContinueToLocationRequestTargetCallFrames.Current,
    });
  }

  private paused(pausedCallback: () => void|undefined, debuggerPausedDetails: DebuggerPausedDetails): boolean {
    const location = debuggerPausedDetails.callFrames[0].location();
    if (location.scriptId === this.scriptId && location.lineNumber === this.lineNumber &&
        location.columnNumber === this.columnNumber) {
      pausedCallback();
      return true;
    }
    return false;
  }

  id(): string {
    return this.debuggerModel.target().id() + ':' + this.scriptId + ':' + this.lineNumber + ':' + this.columnNumber;
  }
}

export interface LocationRange {
  start: Location;
  end: Location;
}

export class BreakLocation extends Location {
  type: Protocol.Debugger.BreakLocationType|undefined;
  constructor(
      debuggerModel: DebuggerModel, scriptId: Protocol.Runtime.ScriptId, lineNumber: number, columnNumber?: number,
      type?: Protocol.Debugger.BreakLocationType) {
    super(debuggerModel, scriptId, lineNumber, columnNumber);
    if (type) {
      this.type = type;
    }
  }

  static override fromPayload(debuggerModel: DebuggerModel, payload: Protocol.Debugger.BreakLocation): BreakLocation {
    return new BreakLocation(debuggerModel, payload.scriptId, payload.lineNumber, payload.columnNumber, payload.type);
  }
}

export interface MissingDebugFiles {
  resourceUrl: Platform.DevToolsPath.UrlString;
  initiator: PageResourceLoadInitiator;
}

export interface MissingDebugInfoDetails {
  details: string;
  resources: MissingDebugFiles[];
}

export class CallFrame {
  debuggerModel: DebuggerModel;
  readonly script: Script;
  payload: Protocol.Debugger.CallFrame;
  readonly #location: Location;
  readonly #scopeChain: Scope[];
  readonly #localScope: Scope|null;
  readonly inlineFrameIndex: number;
  readonly functionName: string;
  readonly #functionLocation: Location|undefined;
  #returnValue: RemoteObject|null;
  missingDebugInfoDetails: MissingDebugInfoDetails|null;
  readonly exception: RemoteObject|null;

  readonly canBeRestarted: boolean;

  constructor(
      debuggerModel: DebuggerModel, script: Script, payload: Protocol.Debugger.CallFrame, inlineFrameIndex?: number,
      functionName?: string, exception: RemoteObject|null = null) {
    this.debuggerModel = debuggerModel;
    this.script = script;
    this.payload = payload;
    this.#location = Location.fromPayload(debuggerModel, payload.location, inlineFrameIndex);
    this.#scopeChain = [];
    this.#localScope = null;
    this.inlineFrameIndex = inlineFrameIndex || 0;
    this.functionName = functionName ?? payload.functionName;
    this.missingDebugInfoDetails = null;
    this.canBeRestarted = Boolean(payload.canBeRestarted);
    this.exception = exception;
    for (let i = 0; i < payload.scopeChain.length; ++i) {
      const scope = new Scope(this, i);
      this.#scopeChain.push(scope);
      if (scope.type() === Protocol.Debugger.ScopeType.Local) {
        this.#localScope = scope;
      }
    }
    if (payload.functionLocation) {
      this.#functionLocation = Location.fromPayload(debuggerModel, payload.functionLocation);
    }
    this.#returnValue =
        payload.returnValue ? this.debuggerModel.runtimeModel().createRemoteObject(payload.returnValue) : null;
  }

  static fromPayloadArray(
      debuggerModel: DebuggerModel, callFrames: Protocol.Debugger.CallFrame[],
      exception: RemoteObject|null): CallFrame[] {
    const result = [];
    for (let i = 0; i < callFrames.length; ++i) {
      const callFrame = callFrames[i];
      const script = debuggerModel.scriptForId(callFrame.location.scriptId);
      if (script) {
        const ex = i === 0 ? exception : null;
        result.push(new CallFrame(debuggerModel, script, callFrame, undefined, undefined, ex));
      }
    }
    return result;
  }

  createVirtualCallFrame(inlineFrameIndex: number, name: string): CallFrame {
    return new CallFrame(this.debuggerModel, this.script, this.payload, inlineFrameIndex, name, this.exception);
  }

  get id(): Protocol.Debugger.CallFrameId {
    return this.payload.callFrameId;
  }

  scopeChain(): Scope[] {
    return this.#scopeChain;
  }

  localScope(): Scope|null {
    return this.#localScope;
  }

  thisObject(): RemoteObject|null {
    return this.payload.this ? this.debuggerModel.runtimeModel().createRemoteObject(this.payload.this) : null;
  }

  returnValue(): RemoteObject|null {
    return this.#returnValue;
  }

  async setReturnValue(expression: string): Promise<RemoteObject|null> {
    if (!this.#returnValue) {
      return null;
    }

    const evaluateResponse = await this.debuggerModel.agent.invoke_evaluateOnCallFrame(
        {callFrameId: this.id, expression, silent: true, objectGroup: 'backtrace'});
    if (evaluateResponse.getError() || evaluateResponse.exceptionDetails) {
      return null;
    }
    const response = await this.debuggerModel.agent.invoke_setReturnValue({newValue: evaluateResponse.result});
    if (response.getError()) {
      return null;
    }
    this.#returnValue = this.debuggerModel.runtimeModel().createRemoteObject(evaluateResponse.result);
    return this.#returnValue;
  }

  location(): Location {
    return this.#location;
  }

  functionLocation(): Location|null {
    return this.#functionLocation || null;
  }

  async evaluate(options: EvaluationOptions): Promise<EvaluationResult> {
    const debuggerModel = this.debuggerModel;
    const runtimeModel = debuggerModel.runtimeModel();

    const evaluateOnCallFrameCallback = debuggerModel.getEvaluateOnCallFrameCallback();
    if (evaluateOnCallFrameCallback) {
      const result = await evaluateOnCallFrameCallback(this, options);
      if (result) {
        return result;
      }
    }

    const response = await this.debuggerModel.agent.invoke_evaluateOnCallFrame({
      callFrameId: this.id,
      expression: