How to use the @yarnpkg/fslib.ppath.isAbsolute function in @yarnpkg/fslib

private async fetchFromDisk(locator: Locator, opts: FetchOptions) {
    const {parentLocator, path} = structUtils.parseFileStyleRange(locator.reference, {protocol: PROTOCOL});

    // If the file target is an absolute path we can directly access it via its
    // location on the disk. Otherwise we must go through the package fs.
    const parentFetch = ppath.isAbsolute(path)
      ? {packageFs: new NodeFS(), prefixPath: PortablePath.root, localPath: PortablePath.root}
      : await opts.fetcher.fetch(parentLocator, opts);

    // If the package fs publicized its "original location" (for example like
    // in the case of "file:" packages), we use it to derive the real location.
    const effectiveParentFetch = parentFetch.localPath
      ? {packageFs: new NodeFS(), prefixPath: parentFetch.localPath}
      : parentFetch;

    // Discard the parent fs unless we really need it to access the files
    if (parentFetch !== effectiveParentFetch && parentFetch.releaseFs)
      parentFetch.releaseFs();

    const sourceFs = effectiveParentFetch.packageFs;
    const sourcePath = ppath.resolve(effectiveParentFetch.prefixPath, path);

async fetch(locator: Locator, opts: FetchOptions) {
    const {parentLocator, path} = structUtils.parseFileStyleRange(locator.reference, {protocol: RAW_LINK_PROTOCOL});

    // If the link target is an absolute path we can directly access it via its
    // location on the disk. Otherwise we must go through the package fs.
    const parentFetch = ppath.isAbsolute(path)
      ? {packageFs: new NodeFS(), prefixPath: PortablePath.root, localPath: PortablePath.root}
      : await opts.fetcher.fetch(parentLocator, opts);

    // If the package fs publicized its "original location" (for example like
    // in the case of "file:" packages), we use it to derive the real location.
    const effectiveParentFetch = parentFetch.localPath
      ? {packageFs: new NodeFS(), prefixPath: parentFetch.localPath}
      : parentFetch;

    // Discard the parent fs unless we really need it to access the files
    if (parentFetch !== effectiveParentFetch && parentFetch.releaseFs)
      parentFetch.releaseFs();

    const sourceFs = effectiveParentFetch.packageFs;
    const sourcePath = ppath.resolve(effectiveParentFetch.prefixPath, path);

return null;

    // We allow disabling the pnp resolution for some subpaths.
    // This is because some projects, often legacy, contain multiple
    // levels of dependencies (ie. a yarn.lock inside a subfolder of
    // a yarn.lock). This is typically solved using workspaces, but
    // not all of them have been converted already.

    if (issuer && isPathIgnored(issuer)) {
      // Absolute paths that seem to belong to a PnP tree are still
      // handled by our runtime even if the issuer isn't. This is
      // because the native Node resolution uses a special version
      // of the `stat` syscall which would otherwise bypass the
      // filesystem layer we require to access the files.

      if (!ppath.isAbsolute(request) || findPackageLocator(request) === null) {
        const result = callNativeResolution(request, issuer);

        if (result === false) {
          throw makeError(
            ErrorCode.BUILTIN_NODE_RESOLUTION_FAILED,
            `The builtin node resolution algorithm was unable to resolve the requested module (it didn't go through the pnp resolver because the issuer was explicitely ignored by the regexp)\n\nRequire request: "${request}"\nRequired by: ${issuer}\n`,
            {request, issuer},
          );
        }

        return npath.toPortablePath(result);
      }
    }

    let unqualifiedPath: PortablePath;

private async fetchFromDisk(locator: Locator, opts: FetchOptions) {
    const {parentLocator, path} = structUtils.parseFileStyleRange(locator.reference, {protocol: PROTOCOL});

    // If the file target is an absolute path we can directly access it via its
    // location on the disk. Otherwise we must go through the package fs.
    const parentFetch = ppath.isAbsolute(path)
      ? {packageFs: new NodeFS(), prefixPath: PortablePath.root, localPath: PortablePath.root}
      : await opts.fetcher.fetch(parentLocator, opts);

    // If the package fs publicized its "original location" (for example like
    // in the case of "file:" packages), we use it to derive the real location.
    const effectiveParentFetch = parentFetch.localPath
      ? {packageFs: new NodeFS(), prefixPath: parentFetch.localPath}
      : parentFetch;

    // Discard the parent fs unless we really need it to access the files
    if (parentFetch !== effectiveParentFetch && parentFetch.releaseFs)
      parentFetch.releaseFs();

    const generatorFs = effectiveParentFetch.packageFs;
    const generatorPath = ppath.resolve(ppath.resolve(generatorFs.getRealPath(), effectiveParentFetch.prefixPath), path);

getLocalPath(locator: Locator, opts: FetchOptions) {
    const {parentLocator, path} = structUtils.parseFileStyleRange(locator.reference, {protocol: RAW_LINK_PROTOCOL});
    if (ppath.isAbsolute(path))
      return path;

    const parentLocalPath = opts.fetcher.getLocalPath(parentLocator, opts);
    if (parentLocalPath === null)
      return null;

    return ppath.resolve(parentLocalPath, path);
  }

for (const [propKey, propDefinition] of Object.entries(definition.properties))
        result.set(propKey, getDefaultValue(configuration, propDefinition));

      return result;
    } break;

    case SettingsType.MAP: {
      return new Map();
    } break;

    case SettingsType.ABSOLUTE_PATH: {
      if (definition.default === null)
        return null;

      if (configuration.projectCwd === null) {
        if (ppath.isAbsolute(definition.default)) {
          return ppath.normalize(definition.default);
        } else if (definition.isNullable || definition.default === null) {
          return null;
        }
      } else {
        if (Array.isArray(definition.default)) {
          return definition.default.map((entry: string) => ppath.resolve(configuration.projectCwd!, entry as PortablePath));
        } else {
          return ppath.resolve(configuration.projectCwd, definition.default);
        }
      }
    } break;

    default: {
      return definition.default;
    } break;

getLocalPath(locator: Locator, opts: FetchOptions) {
    const {parentLocator, path} = structUtils.parseFileStyleRange(locator.reference, {protocol: PROTOCOL});
    if (ppath.isAbsolute(path))
      return path;

    const parentLocalPath = opts.fetcher.getLocalPath(parentLocator, opts);
    if (parentLocalPath === null)
      return null;

    return ppath.resolve(parentLocalPath, path);
  }

tryWorkspaceByCwd(workspaceCwd: PortablePath) {
    if (!ppath.isAbsolute(workspaceCwd))
      workspaceCwd = ppath.resolve(this.cwd, workspaceCwd);

    const workspace = this.workspacesByCwd.get(workspaceCwd);
    if (!workspace)
      return null;

    return workspace;
  }