resolutionCache.ts

import {
    arrayToMap,
    CachedDirectoryStructureHost,
    CharacterCodes,
    clearMap,
    closeFileWatcher,
    closeFileWatcherOf,
    CompilerOptions,
    createModeAwareCache,
    createModuleResolutionCache,
    createMultiMap,
    createTypeReferenceDirectiveResolutionCache,
    createTypeReferenceResolutionLoader,
    Debug,
    Diagnostics,
    directorySeparator,
    DirectoryWatcherCallback,
    emptyArray,
    endsWith,
    Extension,
    extensionIsTS,
    fileExtensionIs,
    fileExtensionIsOneOf,
    FileReference,
    FileWatcher,
    FileWatcherCallback,
    firstDefinedIterator,
    GetCanonicalFileName,
    getDirectoryPath,
    getEffectiveTypeRoots,
    getNormalizedAbsolutePath,
    getRootLength,
    HasInvalidatedResolutions,
    ignoredPaths,
    inferredTypesContainingFile,
    isEmittedFileOfProgram,
    isExternalModuleNameRelative,
    isExternalOrCommonJsModule,
    isNodeModulesDirectory,
    isRootedDiskPath,
    isTraceEnabled,
    loadModuleFromGlobalCache,
    memoize,
    MinimalResolutionCacheHost,
    ModeAwareCache,
    ModuleResolutionCache,
    moduleResolutionNameAndModeGetter,
    mutateMap,
    noopFileWatcher,
    normalizePath,
    PackageId,
    packageIdToString,
    parseNodeModuleFromPath,
    Path,
    pathContainsNodeModules,
    Program,
    removeSuffix,
    removeTrailingDirectorySeparator,
    resolutionExtensionIsTSOrJson,
    ResolutionLoader,
    ResolutionMode,
    ResolvedModuleWithFailedLookupLocations,
    ResolvedProjectReference,
    ResolvedTypeReferenceDirectiveWithFailedLookupLocations,
    resolveModuleName as ts_resolveModuleName,
    returnTrue,
    some,
    SourceFile,
    startsWith,
    stringContains,
    StringLiteralLike,
    trace,
    updateResolutionField,
    WatchDirectoryFlags,
} from "./_namespaces/ts";

/**
 * This is the cache of module/typedirectives resolution that can be retained across program
 *
 * @internal
 */
export interface ResolutionCache {
    startRecordingFilesWithChangedResolutions(): void;
    finishRecordingFilesWithChangedResolutions(): Path[] | undefined;

    resolveModuleNameLiterals(
        moduleLiterals: readonly StringLiteralLike[],
        containingFile: string,
        redirectedReference: ResolvedProjectReference | undefined,
        options: CompilerOptions,
        containingSourceFile: SourceFile,
        reusedNames: readonly StringLiteralLike[] | undefined,
    ): readonly ResolvedModuleWithFailedLookupLocations[];
    resolveTypeReferenceDirectiveReferences<T extends FileReference | string>(
        typeDirectiveReferences: readonly T[],
        containingFile: string,
        redirectedReference: ResolvedProjectReference | undefined,
        options: CompilerOptions,
        containingSourceFile: SourceFile | undefined,
        reusedNames: readonly T[] | undefined
    ): readonly ResolvedTypeReferenceDirectiveWithFailedLookupLocations[];

    resolveSingleModuleNameWithoutWatching(
        moduleName: string,
        containingFile: string,
    ): ResolvedModuleWithFailedLookupLocations;

    invalidateResolutionsOfFailedLookupLocations(): boolean;
    invalidateResolutionOfFile(filePath: Path): void;
    removeResolutionsOfFile(filePath: Path): void;
    removeResolutionsFromProjectReferenceRedirects(filePath: Path): void;
    setFilesWithInvalidatedNonRelativeUnresolvedImports(filesWithUnresolvedImports: Map<Path, readonly string[]>): void;
    createHasInvalidatedResolutions(customHasInvalidatedResolutions: HasInvalidatedResolutions): HasInvalidatedResolutions;
    hasChangedAutomaticTypeDirectiveNames(): boolean;
    isFileWithInvalidatedNonRelativeUnresolvedImports(path: Path): boolean;


    startCachingPerDirectoryResolution(): void;
    finishCachingPerDirectoryResolution(newProgram: Program | undefined, oldProgram: Program | undefined): void;

    updateTypeRootsWatch(): void;
    closeTypeRootsWatch(): void;

    getModuleResolutionCache(): ModuleResolutionCache;

    clear(): void;
}

/** @internal */
export interface ResolutionWithFailedLookupLocations {
    failedLookupLocations?: string[];
    affectingLocations?: string[];
    isInvalidated?: boolean;
    refCount?: number;
    // Files that have this resolution using
    files?: Set<Path>;
}

interface ResolutionWithResolvedFileName {
    resolvedFileName: string | undefined;
    packageId?: PackageId;
}

/** @internal */
export interface CachedResolvedModuleWithFailedLookupLocations extends ResolvedModuleWithFailedLookupLocations, ResolutionWithFailedLookupLocations {
}

interface CachedResolvedTypeReferenceDirectiveWithFailedLookupLocations extends ResolvedTypeReferenceDirectiveWithFailedLookupLocations, ResolutionWithFailedLookupLocations {
}

/** @internal */
export interface ResolutionCacheHost extends MinimalResolutionCacheHost {
    toPath(fileName: string): Path;
    getCanonicalFileName: GetCanonicalFileName;
    getCompilationSettings(): CompilerOptions;
    watchDirectoryOfFailedLookupLocation(directory: string, cb: DirectoryWatcherCallback, flags: WatchDirectoryFlags): FileWatcher;
    watchAffectingFileLocation(file: string, cb: FileWatcherCallback): FileWatcher;
    onInvalidatedResolution(): void;
    watchTypeRootsDirectory(directory: string, cb: DirectoryWatcherCallback, flags: WatchDirectoryFlags): FileWatcher;
    onChangedAutomaticTypeDirectiveNames(): void;
    scheduleInvalidateResolutionsOfFailedLookupLocations(): void;
    getCachedDirectoryStructureHost(): CachedDirectoryStructureHost | undefined;
    projectName?: string;
    getGlobalCache?(): string | undefined;
    globalCacheResolutionModuleName?(externalModuleName: string): string;
    writeLog(s: string): void;
    getCurrentProgram(): Program | undefined;
    fileIsOpen(filePath: Path): boolean;
    onDiscoveredSymlink?(): void;
}

interface FileWatcherOfAffectingLocation {
    /** watcher for the lookup */
    watcher: FileWatcher;
    resolutions: number;
    files: number;
    paths: Set<string>;
}

interface DirectoryWatchesOfFailedLookup {
    /** watcher for the lookup */
    watcher: FileWatcher;
    /** ref count keeping this watch alive */
    refCount: number;
    /** is the directory watched being non recursive */
    nonRecursive?: boolean;
}

interface DirectoryOfFailedLookupWatch {
    dir: string;
    dirPath: Path;
    nonRecursive?: boolean;
}

/** @internal */
export function removeIgnoredPath(path: Path): Path | undefined {
    // Consider whole staging folder as if node_modules changed.
    if (endsWith(path, "/node_modules/.staging")) {
        return removeSuffix(path, "/.staging") as Path;
    }

    return some(ignoredPaths, searchPath => stringContains(path, searchPath)) ?
        undefined :
        path;
}

/**
 * Filter out paths like
 * "/", "/user", "/user/username", "/user/username/folderAtRoot",
 * "c:/", "c:/users", "c:/users/username", "c:/users/username/folderAtRoot", "c:/folderAtRoot"
 * @param dirPath
 *
 * @internal
 */
export function canWatchDirectoryOrFile(dirPath: Path) {
    const rootLength = getRootLength(dirPath);
    if (dirPath.length === rootLength) {
        // Ignore "/", "c:/"
        return false;
    }

    let nextDirectorySeparator = dirPath.indexOf(directorySeparator, rootLength);
    if (nextDirectorySeparator === -1) {
        // ignore "/user", "c:/users" or "c:/folderAtRoot"
        return false;
    }

    let pathPartForUserCheck = dirPath.substring(rootLength, nextDirectorySeparator + 1);
    const isNonDirectorySeparatorRoot = rootLength > 1 || dirPath.charCodeAt(0) !== CharacterCodes.slash;
    if (isNonDirectorySeparatorRoot &&
        dirPath.search(/[a-zA-Z]:/) !== 0 && // Non dos style paths
        pathPartForUserCheck.search(/[a-zA-Z]\$\//) === 0) { // Dos style nextPart
        nextDirectorySeparator = dirPath.indexOf(directorySeparator, nextDirectorySeparator + 1);
        if (nextDirectorySeparator === -1) {
            // ignore "//vda1cs4850/c$/folderAtRoot"
            return false;
        }

        pathPartForUserCheck = dirPath.substring(rootLength + pathPartForUserCheck.length, nextDirectorySeparator + 1);
    }

    if (isNonDirectorySeparatorRoot &&
        pathPartForUserCheck.search(/users\//i) !== 0) {
        // Paths like c:/folderAtRoot/subFolder are allowed
        return true;
    }

    for (let searchIndex = nextDirectorySeparator + 1, searchLevels = 2; searchLevels > 0; searchLevels--) {
        searchIndex = dirPath.indexOf(directorySeparator, searchIndex) + 1;
        if (searchIndex === 0) {
            // Folder isnt at expected minimum levels
            return false;
        }
    }
    return true;
}

type GetResolutionWithResolvedFileName<T extends ResolutionWithFailedLookupLocations = ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName = ResolutionWithResolvedFileName> =
    (resolution: T) => R | undefined;

/** @internal */
export function createResolutionCache(resolutionHost: ResolutionCacheHost, rootDirForResolution: string | undefined, logChangesWhenResolvingModule: boolean): ResolutionCache {
    let filesWithChangedSetOfUnresolvedImports: Path[] | undefined;
    let filesWithInvalidatedResolutions: Set<Path> | undefined;
    let filesWithInvalidatedNonRelativeUnresolvedImports: ReadonlyMap<Path, readonly string[]> | undefined;
    const nonRelativeExternalModuleResolutions = createMultiMap<string, ResolutionWithFailedLookupLocations>();

    const resolutionsWithFailedLookups = new Set<ResolutionWithFailedLookupLocations>();
    const resolutionsWithOnlyAffectingLocations = new Set<ResolutionWithFailedLookupLocations>();
    const resolvedFileToResolution = new Map<string, Set<ResolutionWithFailedLookupLocations>>();
    const impliedFormatPackageJsons = new Map<Path, readonly string[]>();

    let hasChangedAutomaticTypeDirectiveNames = false;
    let affectingPathChecksForFile: Set<string> | undefined;
    let affectingPathChecks: Set<string> | undefined;
    let failedLookupChecks: Set<Path> | undefined;
    let startsWithPathChecks: Set<Path> | undefined;
    let isInDirectoryChecks: Set<Path> | undefined;

    const getCurrentDirectory = memoize(() => resolutionHost.getCurrentDirectory!()); // TODO: GH#18217
    const cachedDirectoryStructureHost = resolutionHost.getCachedDirectoryStructureHost();

    // The resolvedModuleNames and resolvedTypeReferenceDirectives are the cache of resolutions per file.
    // The key in the map is source file's path.
    // The values are Map of resolutions with key being name lookedup.
    const resolvedModuleNames = new Map<Path, ModeAwareCache<CachedResolvedModuleWithFailedLookupLocations>>();
    const moduleResolutionCache = createModuleResolutionCache(
        getCurrentDirectory(),
        resolutionHost.getCanonicalFileName,
        resolutionHost.getCompilationSettings(),
    );

    const resolvedTypeReferenceDirectives = new Map<Path, ModeAwareCache<CachedResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();
    const typeReferenceDirectiveResolutionCache = createTypeReferenceDirectiveResolutionCache(
        getCurrentDirectory(),
        resolutionHost.getCanonicalFileName,
        resolutionHost.getCompilationSettings(),
        moduleResolutionCache.getPackageJsonInfoCache(),
    );

    /**
     * These are the extensions that failed lookup files will have by default,
     * any other extension of failed lookup will be store that path in custom failed lookup path
     * This helps in not having to comb through all resolutions when files are added/removed
     * Note that .d.ts file also has .d.ts extension hence will be part of default extensions
     */
    const failedLookupDefaultExtensions = [Extension.Ts, Extension.Tsx, Extension.Js, Extension.Jsx, Extension.Json];
    const customFailedLookupPaths = new Map<string, number>();

    const directoryWatchesOfFailedLookups = new Map<string, DirectoryWatchesOfFailedLookup>();
    const fileWatchesOfAffectingLocations = new Map<string, FileWatcherOfAffectingLocation>();
    const rootDir = rootDirForResolution && removeTrailingDirectorySeparator(getNormalizedAbsolutePath(rootDirForResolution, getCurrentDirectory()));
    const rootPath = (rootDir && resolutionHost.toPath(rootDir)) as Path; // TODO: GH#18217
    const rootSplitLength = rootPath !== undefined ? rootPath.split(directorySeparator).length : 0;

    // TypeRoot watches for the types that get added as part of getAutomaticTypeDirectiveNames
    const typeRootsWatches = new Map<string, FileWatcher>();

    return {
        getModuleResolutionCache: () => moduleResolutionCache,
        startRecordingFilesWithChangedResolutions,
        finishRecordingFilesWithChangedResolutions,
        // perDirectoryResolvedModuleNames and perDirectoryResolvedTypeReferenceDirectives could be non empty if there was exception during program update
        // (between startCachingPerDirectoryResolution and finishCachingPerDirectoryResolution)
        startCachingPerDirectoryResolution,
        finishCachingPerDirectoryResolution,
        resolveModuleNameLiterals,
        resolveTypeReferenceDirectiveReferences,
        resolveSingleModuleNameWithoutWatching,
        removeResolutionsFromProjectReferenceRedirects,
        removeResolutionsOfFile,
        hasChangedAutomaticTypeDirectiveNames: () => hasChangedAutomaticTypeDirectiveNames,
        invalidateResolutionOfFile,
        invalidateResolutionsOfFailedLookupLocations,
        setFilesWithInvalidatedNonRelativeUnresolvedImports,
        createHasInvalidatedResolutions,
        isFileWithInvalidatedNonRelativeUnresolvedImports,
        updateTypeRootsWatch,
        closeTypeRootsWatch,
        clear
    };

    function getResolvedModule(resolution: CachedResolvedModuleWithFailedLookupLocations) {
        return resolution.resolvedModule;
    }

    function getResolvedTypeReferenceDirective(resolution: CachedResolvedTypeReferenceDirectiveWithFailedLookupLocations) {
        return resolution.resolvedTypeReferenceDirective;
    }

    function isInDirectoryPath(dir: Path | undefined, file: Path) {
        if (dir === undefined || file.length <= dir.length) {
            return false;
        }
        return startsWith(file, dir) && file[dir.length] === directorySeparator;
    }

    function clear() {
        clearMap(directoryWatchesOfFailedLookups, closeFileWatcherOf);
        clearMap(fileWatchesOfAffectingLocations, closeFileWatcherOf);
        customFailedLookupPaths.clear();
        nonRelativeExternalModuleResolutions.clear();
        closeTypeRootsWatch();
        resolvedModuleNames.clear();
        resolvedTypeReferenceDirectives.clear();
        resolvedFileToResolution.clear();
        resolutionsWithFailedLookups.clear();
        resolutionsWithOnlyAffectingLocations.clear();
        failedLookupChecks = undefined;
        startsWithPathChecks = undefined;
        isInDirectoryChecks = undefined;
        affectingPathChecks = undefined;
        affectingPathChecksForFile = undefined;
        moduleResolutionCache.clear();
        typeReferenceDirectiveResolutionCache.clear();
        moduleResolutionCache.update(resolutionHost.getCompilationSettings());
        typeReferenceDirectiveResolutionCache.update(resolutionHost.getCompilationSettings());
        impliedFormatPackageJsons.clear();
        hasChangedAutomaticTypeDirectiveNames = false;
    }

    function startRecordingFilesWithChangedResolutions() {
        filesWithChangedSetOfUnresolvedImports = [];
    }

    function finishRecordingFilesWithChangedResolutions() {
        const collected = filesWithChangedSetOfUnresolvedImports;
        filesWithChangedSetOfUnresolvedImports = undefined;
        return collected;
    }

    function isFileWithInvalidatedNonRelativeUnresolvedImports(path: Path): boolean {
        if (!filesWithInvalidatedNonRelativeUnresolvedImports) {
            return false;
        }

        // Invalidated if file has unresolved imports
        const value = filesWithInvalidatedNonRelativeUnresolvedImports.get(path);
        return !!value && !!value.length;
    }

    function createHasInvalidatedResolutions(customHasInvalidatedResolutions: HasInvalidatedResolutions): HasInvalidatedResolutions {
        // Ensure pending resolutions are applied
        invalidateResolutionsOfFailedLookupLocations();
        const collected = filesWithInvalidatedResolutions;
        filesWithInvalidatedResolutions = undefined;
        return path => customHasInvalidatedResolutions(path) ||
            !!collected?.has(path) ||
            isFileWithInvalidatedNonRelativeUnresolvedImports(path);
    }

    function startCachingPerDirectoryResolution() {
        moduleResolutionCache.clearAllExceptPackageJsonInfoCache();
        typeReferenceDirectiveResolutionCache.clearAllExceptPackageJsonInfoCache();
        // perDirectoryResolvedModuleNames and perDirectoryResolvedTypeReferenceDirectives could be non empty if there was exception during program update
        // (between startCachingPerDirectoryResolution and finishCachingPerDirectoryResolution)
        nonRelativeExternalModuleResolutions.forEach(watchFailedLookupLocationOfNonRelativeModuleResolutions);
        nonRelativeExternalModuleResolutions.clear();
    }

    function finishCachingPerDirectoryResolution(newProgram: Program | undefined, oldProgram: Program | undefined) {
        filesWithInvalidatedNonRelativeUnresolvedImports = undefined;
        nonRelativeExternalModuleResolutions.forEach(watchFailedLookupLocationOfNonRelativeModuleResolutions);
        nonRelativeExternalModuleResolutions.clear();
        // Update file watches
        if (newProgram !== oldProgram) {
            newProgram?.getSourceFiles().forEach(newFile => {
                const expected = isExternalOrCommonJsModule(newFile) ? newFile.packageJsonLocations?.length ?? 0 : 0;
                const existing = impliedFormatPackageJsons.get(newFile.path) ?? emptyArray;
                for (let i = existing.length; i < expected; i++) {
                    createFileWatcherOfAffectingLocation(newFile.packageJsonLocations![i], /*forResolution*/ false);
                }
                if (existing.length > expected) {
                    for (let i = expected; i < existing.length; i++) {
                        fileWatchesOfAffectingLocations.get(existing[i])!.files--;
                    }
                }
                if (expected) impliedFormatPackageJsons.set(newFile.path, newFile.packageJsonLocations!);
                else impliedFormatPackageJsons.delete(newFile.path);
            });
            impliedFormatPackageJsons.forEach((existing, path) => {
                if (!newProgram?.getSourceFileByPath(path)) {
                    existing.forEach(location => fileWatchesOfAffectingLocations.get(location)!.files--);
                    impliedFormatPackageJsons.delete(path);
                }
            });
        }
        directoryWatchesOfFailedLookups.forEach((watcher, path) => {
            if (watcher.refCount === 0) {
                directoryWatchesOfFailedLookups.delete(path);
                watcher.watcher.close();
            }
        });
        fileWatchesOfAffectingLocations.forEach((watcher, path) => {
            if (watcher.files === 0 && watcher.resolutions === 0) {
                fileWatchesOfAffectingLocations.delete(path);
                watcher.watcher.close();
            }
        });

        hasChangedAutomaticTypeDirectiveNames = false;
    }

    function resolveModuleName(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, redirectedReference?: ResolvedProjectReference, mode?: ResolutionMode): CachedResolvedModuleWithFailedLookupLocations {
        const host = resolutionHost.getCompilerHost?.() || resolutionHost;
        const primaryResult = ts_resolveModuleName(moduleName, containingFile, compilerOptions, host, moduleResolutionCache, redirectedReference, mode);
        // return result immediately only if global cache support is not enabled or if it is .ts, .tsx or .d.ts
        if (!resolutionHost.getGlobalCache) {
            return primaryResult;
        }

        // otherwise try to load typings from @types
        const globalCache = resolutionHost.getGlobalCache();
        if (globalCache !== undefined && !isExternalModuleNameRelative(moduleName) && !(primaryResult.resolvedModule && extensionIsTS(primaryResult.resolvedModule.extension))) {
            // create different collection of failed lookup locations for second pass
            // if it will fail and we've already found something during the first pass - we don't want to pollute its results
            const { resolvedModule, failedLookupLocations, affectingLocations, resolutionDiagnostics } = loadModuleFromGlobalCache(
                Debug.checkDefined(resolutionHost.globalCacheResolutionModuleName)(moduleName),
                resolutionHost.projectName,
                compilerOptions,
                host,
                globalCache,
                moduleResolutionCache,
            );
            if (resolvedModule) {
                // Modify existing resolution so its saved in the directory cache as well
                (primaryResult.resolvedModule as any) = resolvedModule;
                primaryResult.failedLookupLocations = updateResolutionField(primaryResult.failedLookupLocations, failedLookupLocations);
                primaryResult.affectingLocations = updateResolutionField(primaryResult.affectingLocations, affectingLocations);
                primaryResult.resolutionDiagnostics = updateResolutionField(primaryResult.resolutionDiagnostics, resolutionDiagnostics);
                return primaryResult;
            }
        }

        // Default return the result from the first pass
        return primaryResult;
    }

    function createModuleResolutionLoader(
        containingFile: string,
        redirectedReference: ResolvedProjectReference | undefined,
        options: CompilerOptions,
    ): ResolutionLoader<StringLiteralLike, ResolvedModuleWithFailedLookupLocations, SourceFile> {
        return {
            nameAndMode: moduleResolutionNameAndModeGetter,
            resolve: (moduleName, resoluionMode) => resolveModuleName(
                moduleName,
                containingFile,
                options,
                redirectedReference,
                resoluionMode,
            ),
        };
    }

    interface ResolveNamesWithLocalCacheInput<Entry, SourceFile, T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName> {
        entries: readonly Entry[];
        containingFile: string;
        containingSourceFile: SourceFile;
        redirectedReference: ResolvedProjectReference | undefined;
        options: CompilerOptions;
        reusedNames?: readonly Entry[];
        perFileCache: Map<Path, ModeAwareCache<T>>;
        loader: ResolutionLoader<Entry, T, SourceFile>;
        getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>;
        shouldRetryResolution: (t: T) => boolean;
        logChanges?: boolean;
    }
    function resolveNamesWithLocalCache<Entry, SourceFile, T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName>({
        entries, containingFile, containingSourceFile, redirectedReference, options,
        perFileCache, reusedNames,
        loader, getResolutionWithResolvedFileName,
        shouldRetryResolution, logChanges,
    }: ResolveNamesWithLocalCacheInput<Entry, SourceFile, T, R>): readonly T[] {
        const path = resolutionHost.toPath(containingFile);
        const resolutionsInFile = perFileCache.get(path) || perFileCache.set(path, createModeAwareCache()).get(path)!;
        const resolvedModules: T[] = [];
        const hasInvalidatedNonRelativeUnresolvedImport = logChanges && isFileWithInvalidatedNonRelativeUnresolvedImports(path);

        // All the resolutions in this file are invalidated if this file wasn't resolved using same redirect
        const program = resolutionHost.getCurrentProgram();
        const oldRedirect = program && program.getResolvedProjectReferenceToRedirect(containingFile);
        const unmatchedRedirects = oldRedirect ?
            !redirectedReference || redirectedReference.sourceFile.path !== oldRedirect.sourceFile.path :
            !!redirectedReference;

        const seenNamesInFile = createModeAwareCache<true>();
        for (const entry of entries) {
            const name = loader.nameAndMode.getName(entry);
            const mode = loader.nameAndMode.getMode(entry, containingSourceFile);
            let resolution = resolutionsInFile.get(name, mode);
            // Resolution is valid if it is present and not invalidated
            if (!seenNamesInFile.has(name, mode) &&
                unmatchedRedirects || !resolution || resolution.isInvalidated ||
                // If the name is unresolved import that was invalidated, recalculate
                (hasInvalidatedNonRelativeUnresolvedImport && !isExternalModuleNameRelative(name) && shouldRetryResolution(resolution))) {
                const existingResolution = resolution;
                resolution = loader.resolve(name, mode);
                if (resolutionHost.onDiscoveredSymlink && resolutionIsSymlink(resolution)) {
                    resolutionHost.onDiscoveredSymlink();
                }
                resolutionsInFile.set(name, mode, resolution);
                watchFailedLookupLocationsOfExternalModuleResolutions(name, resolution, path, getResolutionWithResolvedFileName);
                if (existingResolution) {
                    stopWatchFailedLookupLocationOfResolution(existingResolution, path, getResolutionWithResolvedFileName);
                }

                if (logChanges && filesWithChangedSetOfUnresolvedImports && !resolutionIsEqualTo(existingResolution, resolution)) {
                    filesWithChangedSetOfUnresolvedImports.push(path);
                    // reset log changes to avoid recording the same file multiple times
                    logChanges = false;
                }
            }
            else {
                const host = resolutionHost.getCompilerHost?.() || resolutionHost;
                if (isTraceEnabled(options, host) && !seenNamesInFile.has(name, mode)) {
                    const resolved = getResolutionWithResolvedFileName(resolution);
                    trace(
                        host,
                        perFileCache === resolvedModuleNames as unknown ?
                            resolved?.resolvedFileName ?
                                resolved.packageId ?
                                    Diagnostics.Reusing_resolution_of_module_0_from_1_of_old_program_it_was_successfully_resolved_to_2_with_Package_ID_3 :
                                    Diagnostics.Reusing_resolution_of_module_0_from_1_of_old_program_it_was_successfully_resolved_to_2 :
                                Diagnostics.Reusing_resolution_of_module_0_from_1_of_old_program_it_was_not_resolved :
                            resolved?.resolvedFileName ?
                                resolved.packageId ?
                                    Diagnostics.Reusing_resolution_of_type_reference_directive_0_from_1_of_old_program_it_was_successfully_resolved_to_2_with_Package_ID_3 :
                                    Diagnostics.Reusing_resolution_of_type_reference_directive_0_from_1_of_old_program_it_was_successfully_resolved_to_2 :
                                Diagnostics.Reusing_resolution_of_type_reference_directive_0_from_1_of_old_program_it_was_not_resolved,
                        name,
                        containingFile,
                        resolved?.resolvedFileName,
                        resolved?.packageId && packageIdToString(resolved.packageId)
                    );
                }
            }
            Debug.assert(resolution !== undefined && !resolution.isInvalidated);
            seenNamesInFile.set(name, mode, true);
            resolvedModules.push(resolution);
        }
        reusedNames?.forEach(entry => seenNamesInFile.set(
            loader.nameAndMode.getName(entry),
            loader.nameAndMode.getMode(entry, containingSourceFile),
            true,
        ));
        if (resolutionsInFile.size() !== seenNamesInFile.size()) {
            // Stop watching and remove the unused name
            resolutionsInFile.forEach((resolution, name, mode) => {
                if (!seenNamesInFile.has(name, mode)) {
                    stopWatchFailedLookupLocationOfResolution(resolution, path, getResolutionWithResolvedFileName);
                    resolutionsInFile.delete(name, mode);
                }
            });
        }
        return resolvedModules;

        function resolutionIsEqualTo(oldResolution: T | undefined, newResolution: T | undefined): boolean {
            if (oldResolution === newResolution) {
                return true;
            }
            if (!oldResolution || !newResolution) {
                return false;
            }
            const oldResult = getResolutionWithResolvedFileName(oldResolution);
            const newResult = getResolutionWithResolvedFileName(newResolution);
            if (oldResult === newResult) {
                return true;
            }
            if (!oldResult || !newResult) {
                return false;
            }
            return oldResult.resolvedFileName === newResult.resolvedFileName;
        }
    }

    function resolveTypeReferenceDirectiveReferences<T extends FileReference | string>(
        typeDirectiveReferences: readonly T[],
        containingFile: string,
        redirectedReference: ResolvedProjectReference | undefined,
        options: CompilerOptions,
        containingSourceFile: SourceFile | undefined,
        reusedNames: readonly T[] | undefined
    ): readonly ResolvedTypeReferenceDirectiveWithFailedLookupLocations[]{
        return resolveNamesWithLocalCache({
            entries: typeDirectiveReferences,
            containingFile,
            containingSourceFile,
            redirectedReference,
            options,
            reusedNames,
            perFileCache: resolvedTypeReferenceDirectives,
            loader: createTypeReferenceResolutionLoader(
                containingFile,
                redirectedReference,
                options,
                resolutionHost.getCompilerHost?.() || resolutionHost,
                typeReferenceDirectiveResolutionCache
            ),
            getResolutionWithResolvedFileName: getResolvedTypeReferenceDirective,
            shouldRetryResolution: resolution => resolution.resolvedTypeReferenceDirective === undefined,
        });
    }

    function resolveModuleNameLiterals(
        moduleLiterals: readonly StringLiteralLike[],
        containingFile: string,
        redirectedReference: ResolvedProjectReference | undefined,
        options: CompilerOptions,
        containingSourceFile: SourceFile,
        reusedNames: readonly StringLiteralLike[] | undefined,
    ): readonly ResolvedModuleWithFailedLookupLocations[] {
        return resolveNamesWithLocalCache({
            entries: moduleLiterals,
            containingFile,
            containingSourceFile,
            redirectedReference,
            options,
            reusedNames,
            perFileCache: resolvedModuleNames,
            loader: createModuleResolutionLoader(
                containingFile,
                redirectedReference,
                options,
            ),
            getResolutionWithResolvedFileName: getResolvedModule,
            shouldRetryResolution: resolution => !resolution.resolvedModule || !resolutionExtensionIsTSOrJson(resolution.resolvedModule.extension),
            logChanges: logChangesWhenResolvingModule,
        });
    }

    function resolveSingleModuleNameWithoutWatching(moduleName: string, containingFile: string) {
        const path = resolutionHost.toPath(containingFile);
        const resolutionsInFile = resolvedModuleNames.get(path);
        const resolution = resolutionsInFile?.get(moduleName, /*mode*/ undefined);
        if (resolution && !resolution.isInvalidated) return resolution;
        return resolveModuleName(moduleName, containingFile, resolutionHost.getCompilationSettings());
    }

    function isNodeModulesAtTypesDirectory(dirPath: Path) {
        return endsWith(dirPath, "/node_modules/@types");
    }

    function getDirectoryToWatchFailedLookupLocation(failedLookupLocation: string, failedLookupLocationPath: Path): DirectoryOfFailedLookupWatch | undefined {
        if (isInDirectoryPath(rootPath, failedLookupLocationPath)) {
            // Ensure failed look up is normalized path
            failedLookupLocation = isRootedDiskPath(failedLookupLocation) ? normalizePath(failedLookupLocation) : getNormalizedAbsolutePath(failedLookupLocation, getCurrentDirectory());
            const failedLookupPathSplit = failedLookupLocationPath.split(directorySeparator);
            const failedLookupSplit = failedLookupLocation.split(directorySeparator);
            Debug.assert(failedLookupSplit.length === failedLookupPathSplit.length, `FailedLookup: ${failedLookupLocation} failedLookupLocationPath: ${failedLookupLocationPath}`);
            if (failedLookupPathSplit.length > rootSplitLength + 1) {
                // Instead of watching root, watch directory in root to avoid watching excluded directories not needed for module resolution
                return {
                    dir: failedLookupSplit.slice(0, rootSplitLength + 1).join(directorySeparator),
                    dirPath: failedLookupPathSplit.slice(0, rootSplitLength + 1).join(directorySeparator) as Path
                };
            }
            else {
                // Always watch root directory non recursively
                return {
                    dir: rootDir!,
                    dirPath: rootPath,
                    nonRecursive: false
                };
            }
        }

        return getDirectoryToWatchFromFailedLookupLocationDirectory(
            getDirectoryPath(getNormalizedAbsolutePath(failedLookupLocation, getCurrentDirectory())),
            getDirectoryPath(failedLookupLocationPath)
        );
    }

    function getDirectoryToWatchFromFailedLookupLocationDirectory(dir: string, dirPath: Path): DirectoryOfFailedLookupWatch | undefined {
        // If directory path contains node module, get the most parent node_modules directory for watching
        while (pathContainsNodeModules(dirPath)) {
            dir = getDirectoryPath(dir);
            dirPath = getDirectoryPath(dirPath);
        }

        // If the directory is node_modules use it to watch, always watch it recursively
        if (isNodeModulesDirectory(dirPath)) {
            return canWatchDirectoryOrFile(getDirectoryPath(dirPath)) ? { dir, dirPath } : undefined;
        }

        let nonRecursive = true;
        // Use some ancestor of the root directory
        let subDirectoryPath: Path | undefined, subDirectory: string | undefined;
        if (rootPath !== undefined) {
            while (!isInDirectoryPath(dirPath, rootPath)) {
                const parentPath = getDirectoryPath(dirPath);
                if (parentPath === dirPath) {
                    break;
                }
                nonRecursive = false;
                subDirectoryPath = dirPath;
                subDirectory = dir;
                dirPath = parentPath;
                dir = getDirectoryPath(dir);
            }
        }

        return canWatchDirectoryOrFile(dirPath) ? { dir: subDirectory || dir, dirPath: subDirectoryPath || dirPath, nonRecursive } : undefined;
    }

    function isPathWithDefaultFailedLookupExtension(path: Path) {
        return fileExtensionIsOneOf(path, failedLookupDefaultExtensions);
    }

    function watchFailedLookupLocationsOfExternalModuleResolutions<T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName>(
        name: string,
        resolution: T,
        filePath: Path,
        getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>,
    ) {
        if (resolution.refCount) {
            resolution.refCount++;
            Debug.assertIsDefined(resolution.files);
        }
        else {
            resolution.refCount = 1;
            Debug.assert(!resolution.files?.size); // This resolution shouldnt be referenced by any file yet
            if (isExternalModuleNameRelative(name)) {
                watchFailedLookupLocationOfResolution(resolution);
            }
            else {
                nonRelativeExternalModuleResolutions.add(name, resolution);
            }
            const resolved = getResolutionWithResolvedFileName(resolution);
            if (resolved && resolved.resolvedFileName) {
                const key = resolutionHost.toPath(resolved.resolvedFileName);
                let resolutions = resolvedFileToResolution.get(key);
                if (!resolutions) resolvedFileToResolution.set(key, resolutions = new Set());
                resolutions.add(resolution);
            }
        }
        (resolution.files ??= new Set()).add(filePath);
    }

    function watchFailedLookupLocationOfResolution(resolution: ResolutionWithFailedLookupLocations) {
        Debug.assert(!!resolution.refCount);

        const { failedLookupLocations, affectingLocations } = resolution;
        if (!failedLookupLocations?.length && !affectingLocations?.length) return;
        if (failedLookupLocations?.length) resolutionsWithFailedLookups.add(resolution);

        let setAtRoot = false;
        if (failedLookupLocations) {
            for (const failedLookupLocation of failedLookupLocations) {
                const failedLookupLocationPath = resolutionHost.toPath(failedLookupLocation);
                const toWatch = getDirectoryToWatchFailedLookupLocation(failedLookupLocation, failedLookupLocationPath);
                if (toWatch) {
                    const { dir, dirPath, nonRecursive } = toWatch;
                    // If the failed lookup location path is not one of the supported extensions,
                    // store it in the custom path
                    if (!isPathWithDefaultFailedLookupExtension(failedLookupLocationPath)) {
                        const refCount = customFailedLookupPaths.get(failedLookupLocationPath) || 0;
                        customFailedLookupPaths.set(failedLookupLocationPath, refCount + 1);
                    }
                    if (dirPath === rootPath) {
                        Debug.assert(!nonRecursive);
                        setAtRoot = true;
                    }
                    else {
                        setDirectoryWatcher(dir, dirPath, nonRecursive);
                    }
                }
            }

            if (setAtRoot) {
                // This is always non recursive
                setDirectoryWatcher(rootDir!, rootPath, /*nonRecursive*/ true); // TODO: GH#18217
            }
        }
        watchAffectingLocationsOfResolution(resolution, !failedLookupLocations?.length);
    }

    function watchAffectingLocationsOfResolution(resolution: ResolutionWithFailedLookupLocations, addToResolutionsWithOnlyAffectingLocations: boolean) {
        Debug.assert(!!resolution.refCount);
        const { affectingLocations } = resolution;
        if (!affectingLocations?.length) return;
        if (addToResolutionsWithOnlyAffectingLocations) resolutionsWithOnlyAffectingLocations.add(resolution);
        // Watch package json
        for (const affectingLocation of affectingLocations) {
            createFileWatcherOfAffectingLocation(affectingLocation, /*forResolution*/ true);
        }
    }

    function createFileWatcherOfAffectingLocation(affectingLocation: string, forResolution: boolean) {
        const fileWatcher = fileWatchesOfAffectingLocations.get(affectingLocation);
        if (fileWatcher) {
            if (forResolution) fileWatcher.resolutions++;
            else fileWatcher.files++;
            return;
        }
        let locationToWatch = affectingLocation;
        if (resolutionHost.realpath) {
            locationToWatch = resolutionHost.realpath(affectingLocation);
            if (affectingLocation !== locationToWatch) {
                const fileWatcher = fileWatchesOfAffectingLocations.get(locationToWatch);
                if (fileWatcher) {
                    if (forResolution) fileWatcher.resolutions++;
                    else fileWatcher.files++;
                    fileWatcher.paths.add(affectingLocation);
                    fileWatchesOfAffectingLocations.set(affectingLocation, fileWatcher);
                    return;
                }
            }
        }
        const paths = new Set<string>();
        paths.add(locationToWatch);
        let actualWatcher = canWatchDirectoryOrFile(resolutionHost.toPath(locationToWatch)) ?
            resolutionHost.watchAffectingFileLocation(locationToWatch, (fileName, eventKind) => {
                cachedDirectoryStructureHost?.addOrDeleteFile(fileName, resolutionHost.toPath(locationToWatch), eventKind);
                const packageJsonMap = moduleResolutionCache.getPackageJsonInfoCache().getInternalMap();
                paths.forEach(path => {
                    if (watcher.resolutions) (affectingPathChecks ??= new Set()).add(path);
                    if (watcher.files) (affectingPathChecksForFile ??= new Set()).add(path);
                    packageJsonMap?.delete(resolutionHost.toPath(path));
                });
                resolutionHost.scheduleInvalidateResolutionsOfFailedLookupLocations();
            }) : noopFileWatcher;
        const watcher: FileWatcherOfAffectingLocation = {
            watcher: actualWatcher !== noopFileWatcher ? {
                close: () => {
                    actualWatcher.close();
                    // Ensure when watching symlinked package.json, we can close the actual file watcher only once
                    actualWatcher = noopFileWatcher;
                }
            } : actualWatcher,
            resolutions: forResolution ? 1 : 0,
            files: forResolution ? 0 : 1,
            paths,
        };
        fileWatchesOfAffectingLocations.set(locationToWatch, watcher);
        if (affectingLocation !== locationToWatch) {
            fileWatchesOfAffectingLocations.set(affectingLocation, watcher);
            paths.add(affectingLocation);
        }
    }

    function watchFailedLookupLocationOfNonRelativeModuleResolutions(resolutions: ResolutionWithFailedLookupLocations[], name: string) {
        const program = resolutionHost.getCurrentProgram();
        if (!program || !program.getTypeChecker().tryFindAmbientModuleWithoutAugmentations(name)) {
            resolutions.forEach(watchFailedLookupLocationOfResolution);
        }
        else {
            resolutions.forEach(resolution => watchAffectingLocationsOfResolution(resolution, /*addToResolutionsWithOnlyAffectingLocations*/ true));
        }
    }

    function setDirectoryWatcher(dir: string, dirPath: Path, nonRecursive?: boolean) {
        const dirWatcher = directoryWatchesOfFailedLookups.get(dirPath);
        if (dirWatcher) {
            Debug.assert(!!nonRecursive === !!dirWatcher.nonRecursive);
            dirWatcher.refCount++;
        }
        else {
            directoryWatchesOfFailedLookups.set(dirPath, { watcher: createDirectoryWatcher(dir, dirPath, nonRecursive), refCount: 1, nonRecursive });
        }
    }

    function stopWatchFailedLookupLocationOfResolution<T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName>(
        resolution: T,
        filePath: Path,
        getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>,
    ) {
        Debug.checkDefined(resolution.files).delete(filePath);
        resolution.refCount!--;
        if (resolution.refCount) {
            return;
        }
        const resolved = getResolutionWithResolvedFileName(resolution);
        if (resolved && resolved.resolvedFileName) {
            const key = resolutionHost.toPath(resolved.resolvedFileName);
            const resolutions = resolvedFileToResolution.get(key);
            if (resolutions?.delete(resolution) && !resolutions.size) resolvedFileToResolution.delete(key);
        }

        const { failedLookupLocations, affectingLocations } = resolution;
        if (resolutionsWithFailedLookups.delete(resolution)) {
            let removeAtRoot = false;
            for (const failedLookupLocation of failedLookupLocations!) {
                const failedLookupLocationPath = resolutionHost.toPath(failedLookupLocation);
                const toWatch = getDirectoryToWatchFailedLookupLocation(failedLookupLocation, failedLookupLocationPath);
                if (toWatch) {
                    const { dirPath } = toWatch;
                    const refCount = customFailedLookupPaths.get(failedLookupLocationPath);
                    if (refCount) {
                        if (refCount === 1) {
                            customFailedLookupPaths.delete(failedLookupLocationPath);
                        }
                        else {
                            Debug.assert(refCount > 1);
                            customFailedLookupPaths.set(failedLookupLocationPath, refCount - 1);
                        }
                    }

                    if (dirPath === rootPath) {
                        removeAtRoot = true;
                    }
                    else {
                        removeDirectoryWatcher(dirPath);
                    }
                }
            }
            if (removeAtRoot) {
                removeDirectoryWatcher(rootPath);
            }
        }
        else if (affectingLocations?.length) {
            resolutionsWithOnlyAffectingLocations.delete(resolution);
        }

        if (affectingLocations) {
            for (const affectingLocation of affectingLocations) {
                const watcher = fileWatchesOfAffectingLocations.get(affectingLocation)!;
                watcher.resolutions--;
            }
        }
    }

    function removeDirectoryWatcher(dirPath: string) {
        const dirWatcher = directoryWatchesOfFailedLookups.get(dirPath)!;
        // Do not close the watcher yet since it might be needed by other failed lookup locations.
        dirWatcher.refCount--;
    }

    function createDirectoryWatcher(directory: string, dirPath: Path, nonRecursive: boolean | undefined) {
        return resolutionHost.watchDirectoryOfFailedLookupLocation(directory, fileOrDirectory => {
            const fileOrDirectoryPath = resolutionHost.toPath(fileOrDirectory);
            if (cachedDirectoryStructureHost) {
                // Since the file existence changed, update the sourceFiles cache
                cachedDirectoryStructureHost.addOrDeleteFileOrDirectory(fileOrDirectory, fileOrDirectoryPath);
            }

            scheduleInvalidateResolutionOfFailedLookupLocation(fileOrDirectoryPath, dirPath === fileOrDirectoryPath);
        }, nonRecursive ? WatchDirectoryFlags.None : WatchDirectoryFlags.Recursive);
    }