TypeScript/src/compiler/builder.ts

import {
    addRange,
    AffectedFileResult,
    append,
    arrayFrom,
    arrayToMap,
    BuilderProgram,
    BuilderProgramHost,
    BuilderState,
    BuildInfo,
    CancellationToken,
    CommandLineOption,
    compareStringsCaseSensitive,
    compareValues,
    CompilerHost,
    CompilerOptions,
    compilerOptionsAffectDeclarationPath,
    compilerOptionsAffectEmit,
    compilerOptionsAffectSemanticDiagnostics,
    CompilerOptionsValue,
    concatenate,
    convertToOptionsWithAbsolutePaths,
    createGetCanonicalFileName,
    createModuleNotFoundChain,
    createProgram,
    CustomTransformers,
    Debug,
    Diagnostic,
    DiagnosticCategory,
    DiagnosticMessageChain,
    DiagnosticRelatedInformation,
    DiagnosticWithLocation,
    EmitAndSemanticDiagnosticsBuilderProgram,
    EmitOnly,
    EmitResult,
    emitSkippedWithNoDiagnostics,
    emptyArray,
    ensurePathIsNonModuleName,
    FileIncludeKind,
    filterSemanticDiagnostics,
    forEach,
    forEachEntry,
    forEachKey,
    generateDjb2Hash,
    getDirectoryPath,
    getEmitDeclarations,
    getIsolatedModules,
    getNormalizedAbsolutePath,
    getOptionsNameMap,
    getOwnKeys,
    getRelativePathFromDirectory,
    getSourceFileOfNode,
    getTsBuildInfoEmitOutputFilePath,
    handleNoEmitOptions,
    HostForComputeHash,
    isArray,
    isDeclarationFileName,
    isIncrementalCompilation,
    isJsonSourceFile,
    isNumber,
    isString,
    mapDefinedIterator,
    maybeBind,
    noop,
    notImplemented,
    Path,
    Program,
    ProjectReference,
    ReadBuildProgramHost,
    ReadonlyCollection,
    RepopulateDiagnosticChainInfo,
    RepopulateModuleNotFoundDiagnosticChain,
    returnFalse,
    returnUndefined,
    sameMap,
    SemanticDiagnosticsBuilderProgram,
    SignatureInfo,
    skipAlias,
    skipTypeCheckingIgnoringNoCheck,
    some,
    SourceFile,
    sourceFileMayBeEmitted,
    SourceMapEmitResult,
    SymbolFlags,
    toPath,
    tryAddToSet,
    version,
    WriteFileCallback,
    WriteFileCallbackData,
} from "./_namespaces/ts.js";

/** @internal */
export interface ReusableDiagnostic extends ReusableDiagnosticRelatedInformation {
    /** May store more in future. For now, this will simply be `true` to indicate when a diagnostic is an unused-identifier diagnostic. */
    reportsUnnecessary?: {};
    reportDeprecated?: {};
    source?: string;
    relatedInformation?: ReusableDiagnosticRelatedInformation[];
    skippedOn?: keyof CompilerOptions;
}

/** @internal */
export interface ReusableDiagnosticRelatedInformation {
    category: DiagnosticCategory;
    code: number;
    file: string | undefined | false;
    start: number | undefined;
    length: number | undefined;
    messageText: string | ReusableDiagnosticMessageChain;
}

/** @internal */
export interface ReusableRepopulateModuleNotFoundChain {
    info: RepopulateModuleNotFoundDiagnosticChain;
    next?: ReusableDiagnosticMessageChain[];
}

/** @internal */
export type SerializedDiagnosticMessageChain = Omit<DiagnosticMessageChain, "next" | "repopulateInfo"> & {
    next?: ReusableDiagnosticMessageChain[];
};

/** @internal */
export type ReusableDiagnosticMessageChain = SerializedDiagnosticMessageChain | ReusableRepopulateModuleNotFoundChain;

/**
 * Signature (Hash of d.ts emitted), is string if it was emitted using same d.ts.map option as what compilerOptions indicate, otherwise tuple of string
 *
 * @internal
 */
export type EmitSignature = string | [signature: string];

/** @internal */
export interface ReusableBuilderProgramState extends BuilderState {
    /**
     * Cache of bind and check diagnostics for files with their Path being the key
     */
    semanticDiagnosticsPerFile: Map<Path, readonly ReusableDiagnostic[] | readonly Diagnostic[]>;
    /** Cache of dts emit diagnostics for files with their Path being the key */
    emitDiagnosticsPerFile?: Map<Path, readonly ReusableDiagnostic[] | readonly Diagnostic[]> | undefined;
    /**
     * The map has key by source file's path that has been changed
     */
    changedFilesSet?: Set<Path>;
    /**
     * program corresponding to this state
     */
    program?: Program | undefined;
    /**
     * compilerOptions for the program
     */
    compilerOptions: CompilerOptions;
    /**
     * Files pending to be emitted
     */
    affectedFilesPendingEmit?: ReadonlyMap<Path, BuilderFileEmit>;
    /**
     * emitKind pending for a program with --out
     */
    programEmitPending?: BuilderFileEmit;
    /** If semantic diagnsotic check is pending */
    checkPending?: true;
    /*
     * true if semantic diagnostics are ReusableDiagnostic instead of Diagnostic
     */
    hasReusableDiagnostic?: true;
    /**
     * Hash of d.ts emitted for the file, use to track when emit of d.ts changes
     */
    emitSignatures?: Map<Path, EmitSignature>;
    /**
     * Hash of d.ts emit with --out
     */
    outSignature?: EmitSignature;
    /**
     * Name of the file whose dts was the latest to change
     */
    latestChangedDtsFile: string | undefined;
    /** Recorded if program had errors */
    hasErrors?: boolean;
}

// dprint-ignore
/** @internal */
export const enum BuilderFileEmit {
    None                = 0,
    Js                  = 1 << 0,                       // emit js file
    JsMap               = 1 << 1,                       // emit js.map file
    JsInlineMap         = 1 << 2,                       // emit inline source map in js file
    Dts                 = 1 << 3,                       // emit d.ts file
    DtsMap              = 1 << 4,                       // emit d.ts.map file

    AllJs               = Js | JsMap | JsInlineMap,
    AllDts              = Dts | DtsMap,
    All                 = AllJs | AllDts,
}

/**
 * State to store the changed files, affected files and cache semantic diagnostics
 *
 * @internal
 */
// TODO: GH#18217 Properties of this interface are frequently asserted to be defined.
export interface BuilderProgramState extends BuilderState, ReusableBuilderProgramState {
    /**
     * Cache of bind and check diagnostics for files with their Path being the key
     */
    semanticDiagnosticsPerFile: Map<Path, readonly Diagnostic[]>;
    /** Cache of dts emit diagnostics for files with their Path being the key */
    emitDiagnosticsPerFile?: Map<Path, readonly Diagnostic[]> | undefined;
    /**
     * The map has key by source file's path that has been changed
     */
    changedFilesSet: Set<Path>;
    /**
     * Set of affected files being iterated
     */
    affectedFiles?: readonly SourceFile[] | undefined;
    /**
     * Current index to retrieve affected file from
     */
    affectedFilesIndex: number | undefined;
    /**
     * Current changed file for iterating over affected files
     */
    currentChangedFilePath?: Path | undefined;
    /**
     * Already seen affected files
     */
    seenAffectedFiles: Set<Path> | undefined;
    /**
     * whether this program has cleaned semantic diagnostics cache for lib files
     */
    cleanedDiagnosticsOfLibFiles?: boolean;
    /**
     * True if the semantic diagnostics were copied from the old state
     */
    semanticDiagnosticsFromOldState?: Set<Path>;
    /**
     * Records if change in dts emit was detected
     */
    hasChangedEmitSignature?: boolean;
    /**
     * Files pending to be emitted
     */
    affectedFilesPendingEmit?: Map<Path, BuilderFileEmit>;
    /**
     * true if build info is emitted
     */
    buildInfoEmitPending: boolean;
    /**
     * Already seen emitted files
     */
    seenEmittedFiles: Map<Path, BuilderFileEmit> | undefined;
    /** Already seen program emit */
    seenProgramEmit: BuilderFileEmit | undefined;
    hasErrorsFromOldState?: boolean;
}

interface BuilderProgramStateWithDefinedProgram extends BuilderProgramState {
    program: Program;
}
function isBuilderProgramStateWithDefinedProgram(state: ReusableBuilderProgramState): state is BuilderProgramStateWithDefinedProgram {
    return state.program !== undefined;
}
function toBuilderProgramStateWithDefinedProgram(state: ReusableBuilderProgramState): BuilderProgramStateWithDefinedProgram {
    Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
    return state;
}

/**
 * Get flags determining what all needs to be emitted
 *
 * @internal
 */
export function getBuilderFileEmit(options: CompilerOptions) {
    let result = BuilderFileEmit.Js;
    if (options.sourceMap) result = result | BuilderFileEmit.JsMap;
    if (options.inlineSourceMap) result = result | BuilderFileEmit.JsInlineMap;
    if (getEmitDeclarations(options)) result = result | BuilderFileEmit.Dts;
    if (options.declarationMap) result = result | BuilderFileEmit.DtsMap;
    if (options.emitDeclarationOnly) result = result & BuilderFileEmit.AllDts;
    return result;
}

/**
 * Determining what all is pending to be emitted based on previous options or previous file emit flags
 *
 * @internal
 */
export function getPendingEmitKind(
    optionsOrEmitKind: CompilerOptions | BuilderFileEmit,
    oldOptionsOrEmitKind: CompilerOptions | BuilderFileEmit | undefined,
): BuilderFileEmit {
    const oldEmitKind = oldOptionsOrEmitKind && (isNumber(oldOptionsOrEmitKind) ? oldOptionsOrEmitKind : getBuilderFileEmit(oldOptionsOrEmitKind));
    const emitKind = isNumber(optionsOrEmitKind) ? optionsOrEmitKind : getBuilderFileEmit(optionsOrEmitKind);
    if (oldEmitKind === emitKind) return BuilderFileEmit.None;
    if (!oldEmitKind || !emitKind) return emitKind;
    const diff = oldEmitKind ^ emitKind;
    let result = BuilderFileEmit.None;
    // If there is diff in Js emit, pending emit is js emit flags
    if (diff & BuilderFileEmit.AllJs) result = emitKind & BuilderFileEmit.AllJs;
    // If there is diff in Dts emit, pending emit is dts emit flags
    if (diff & BuilderFileEmit.AllDts) result = result | (emitKind & BuilderFileEmit.AllDts);
    return result;
}

function hasSameKeys(
    map1: ReadonlyCollection<string> | undefined,
    map2: ReadonlyCollection<string> | undefined,
): boolean {
    // Has same size and every key is present in both maps
    return map1 === map2 || map1 !== undefined && map2 !== undefined && map1.size === map2.size && !forEachKey(map1, key => !map2.has(key));
}

/**
 * Create the state so that we can iterate on changedFiles/affected files
 */
function createBuilderProgramState(
    newProgram: Program,
    oldState: Readonly<ReusableBuilderProgramState> | undefined,
): BuilderProgramState {
    const state = BuilderState.create(newProgram, oldState, /*disableUseFileVersionAsSignature*/ false) as BuilderProgramState;
    state.program = newProgram;
    const compilerOptions = newProgram.getCompilerOptions();
    state.compilerOptions = compilerOptions;
    const outFilePath = compilerOptions.outFile;
    state.semanticDiagnosticsPerFile = new Map();
    if (outFilePath && compilerOptions.composite && oldState?.outSignature && outFilePath === oldState.compilerOptions.outFile) {
        state.outSignature = oldState.outSignature && getEmitSignatureFromOldSignature(compilerOptions, oldState.compilerOptions, oldState.outSignature);
    }
    state.changedFilesSet = new Set();
    state.latestChangedDtsFile = compilerOptions.composite ? oldState?.latestChangedDtsFile : undefined;
    state.checkPending = state.compilerOptions.noCheck ? true : undefined;

    const useOldState = BuilderState.canReuseOldState(state.referencedMap, oldState);
    const oldCompilerOptions = useOldState ? oldState!.compilerOptions : undefined;
    let canCopySemanticDiagnostics = useOldState &&
        !compilerOptionsAffectSemanticDiagnostics(compilerOptions, oldCompilerOptions!);
    // We can only reuse emit signatures (i.e. .d.ts signatures) if the .d.ts file is unchanged,
    // which will eg be depedent on change in options like declarationDir and outDir options are unchanged.
    // We need to look in oldState.compilerOptions, rather than oldCompilerOptions (i.e.we need to disregard useOldState) because
    // oldCompilerOptions can be undefined if there was change in say module from None to some other option
    // which would make useOldState as false since we can now use reference maps that are needed to track what to emit, what to check etc
    // but that option change does not affect d.ts file name so emitSignatures should still be reused.
    const canCopyEmitSignatures = compilerOptions.composite &&
        oldState?.emitSignatures &&
        !outFilePath &&
        !compilerOptionsAffectDeclarationPath(compilerOptions, oldState.compilerOptions);
    let canCopyEmitDiagnostics = true;
    if (useOldState) {
        // Copy old state's changed files set
        oldState!.changedFilesSet?.forEach(value => state.changedFilesSet.add(value));
        if (!outFilePath && oldState!.affectedFilesPendingEmit?.size) {
            state.affectedFilesPendingEmit = new Map(oldState!.affectedFilesPendingEmit);
            state.seenAffectedFiles = new Set();
        }
        state.programEmitPending = oldState!.programEmitPending;
        // If there is changeSet with --outFile, cannot copy semantic diagnsotics or emitDiagnostics
        // as they all need to be calculated again all together since we dont know whats the affected file set because of the way d.ts works
        if (outFilePath && state.changedFilesSet.size) {
            canCopySemanticDiagnostics = false;
            canCopyEmitDiagnostics = false;
        }
        state.hasErrorsFromOldState = oldState!.hasErrors;
    }
    else {
        // We arent using old state, so atleast emit buildInfo with current information
        state.buildInfoEmitPending = isIncrementalCompilation(compilerOptions);
    }

    // Update changed files and copy semantic diagnostics if we can
    const referencedMap = state.referencedMap;
    const oldReferencedMap = useOldState ? oldState!.referencedMap : undefined;
    const copyDeclarationFileDiagnostics = canCopySemanticDiagnostics && !compilerOptions.skipLibCheck === !oldCompilerOptions!.skipLibCheck;
    const copyLibFileDiagnostics = copyDeclarationFileDiagnostics && !compilerOptions.skipDefaultLibCheck === !oldCompilerOptions!.skipDefaultLibCheck;
    state.fileInfos.forEach((info, sourceFilePath) => {
        let oldInfo: Readonly<BuilderState.FileInfo> | undefined;
        let newReferences: ReadonlySet<Path> | undefined;

        // if not using old state, every file is changed
        if (
            !useOldState ||
            // File wasn't present in old state
            !(oldInfo = oldState!.fileInfos.get(sourceFilePath)) ||
            // versions dont match
            oldInfo.version !== info.version ||
            // Implied formats dont match
            oldInfo.impliedFormat !== info.impliedFormat ||
            // Referenced files changed
            !hasSameKeys(newReferences = referencedMap && referencedMap.getValues(sourceFilePath), oldReferencedMap && oldReferencedMap.getValues(sourceFilePath)) ||
            // Referenced file was deleted in the new program
            newReferences && forEachKey(newReferences, path => !state.fileInfos.has(path) && oldState!.fileInfos.has(path))
        ) {
            // Register file as changed file and do not copy semantic diagnostics, since all changed files need to be re-evaluated
            addFileToChangeSet(sourceFilePath);
        }
        else {
            const sourceFile = newProgram.getSourceFileByPath(sourceFilePath)!;
            const emitDiagnostics = canCopyEmitDiagnostics ?
                oldState!.emitDiagnosticsPerFile?.get(sourceFilePath) : undefined;
            if (emitDiagnostics) {
                (state.emitDiagnosticsPerFile ??= new Map()).set(
                    sourceFilePath,
                    oldState!.hasReusableDiagnostic ?
                        convertToDiagnostics(emitDiagnostics as readonly ReusableDiagnostic[], sourceFilePath, newProgram) :
                        repopulateDiagnostics(emitDiagnostics as readonly Diagnostic[], newProgram),
                );
            }

            if (canCopySemanticDiagnostics) {
                if (sourceFile.isDeclarationFile && !copyDeclarationFileDiagnostics) return;
                if (sourceFile.hasNoDefaultLib && !copyLibFileDiagnostics) return;

                // Unchanged file copy diagnostics
                const diagnostics = oldState!.semanticDiagnosticsPerFile.get(sourceFilePath);
                if (diagnostics) {
                    state.semanticDiagnosticsPerFile.set(
                        sourceFilePath,
                        oldState!.hasReusableDiagnostic ?
                            convertToDiagnostics(diagnostics as readonly ReusableDiagnostic[], sourceFilePath, newProgram) :
                            repopulateDiagnostics(diagnostics as readonly Diagnostic[], newProgram),
                    );
                    (state.semanticDiagnosticsFromOldState ??= new Set()).add(sourceFilePath);
                }
            }
        }
        if (canCopyEmitSignatures) {
            const oldEmitSignature = oldState.emitSignatures.get(sourceFilePath);
            if (oldEmitSignature) {
                (state.emitSignatures ??= new Map()).set(sourceFilePath, getEmitSignatureFromOldSignature(compilerOptions, oldState.compilerOptions, oldEmitSignature));
            }
        }
    });

    // If the global file is removed, add all files as changed
    if (
        useOldState && forEachEntry(oldState!.fileInfos, (info, sourceFilePath) => {
            if (state.fileInfos.has(sourceFilePath)) return false;
            if (info.affectsGlobalScope) return true;
            // if file is deleted we need to write buildInfo again
            state.buildInfoEmitPending = true;
            return !!outFilePath;
        })
    ) {
        BuilderState.getAllFilesExcludingDefaultLibraryFile(state, newProgram, /*firstSourceFile*/ undefined)
            .forEach(file => addFileToChangeSet(file.resolvedPath));
    }
    else if (oldCompilerOptions) {
        // If options affect emit, then we need to do complete emit per compiler options
        // otherwise only the js or dts that needs to emitted because its different from previously emitted options
        const pendingEmitKind = compilerOptionsAffectEmit(compilerOptions, oldCompilerOptions) ?
            getBuilderFileEmit(compilerOptions) :
            getPendingEmitKind(compilerOptions, oldCompilerOptions);
        if (pendingEmitKind !== BuilderFileEmit.None) {
            if (!outFilePath) {
                // Add all files to affectedFilesPendingEmit since emit changed
                newProgram.getSourceFiles().forEach(f => {
                    // Add to affectedFilesPending emit only if not changed since any changed file will do full emit
                    if (!state.changedFilesSet.has(f.resolvedPath)) {
                        addToAffectedFilesPendingEmit(
                            state,
                            f.resolvedPath,
                            pendingEmitKind,
                        );
                    }
                });
                Debug.assert(!state.seenAffectedFiles || !state.seenAffectedFiles.size);
                state.seenAffectedFiles = state.seenAffectedFiles || new Set();
            }
            else if (!state.changedFilesSet.size) {
                state.programEmitPending = state.programEmitPending ?
                    state.programEmitPending | pendingEmitKind :
                    pendingEmitKind;
            }
            state.buildInfoEmitPending = true;
        }
    }
    if (
        useOldState &&
        state.semanticDiagnosticsPerFile.size !== state.fileInfos.size &&
        oldState!.checkPending !== state.checkPending
    ) state.buildInfoEmitPending = true;
    return state;

    function addFileToChangeSet(path: Path) {
        state.changedFilesSet.add(path);
        if (outFilePath) {
            // If there is changeSet with --outFile, cannot copy semantic diagnsotics or emitDiagnostics
            // as they all need to be calculated again all together since we dont know whats the affected file set because of the way d.ts works
            canCopySemanticDiagnostics = false;
            canCopyEmitDiagnostics = false;
            state.semanticDiagnosticsFromOldState = undefined;
            state.semanticDiagnosticsPerFile.clear();
            state.emitDiagnosticsPerFile = undefined;
        }
        state.buildInfoEmitPending = true;
        // Setting this to undefined as changed files means full emit so no need to track emit explicitly
        state.programEmitPending = undefined;
    }
}

/**
 * Covert to Emit signature based on oldOptions and EmitSignature format
 * If d.ts map options differ then swap the format, otherwise use as is
 */
function getEmitSignatureFromOldSignature(
    options: CompilerOptions,
    oldOptions: CompilerOptions,
    oldEmitSignature: EmitSignature,
): EmitSignature {
    return !!options.declarationMap === !!oldOptions.declarationMap ?
        // Use same format of signature
        oldEmitSignature :
        // Convert to different format
        isString(oldEmitSignature) ? [oldEmitSignature] : oldEmitSignature[0];
}

function repopulateDiagnostics(
    diagnostics: readonly Diagnostic[],
    newProgram: Program,
): readonly Diagnostic[] {
    if (!diagnostics.length) return diagnostics;
    return sameMap(diagnostics, diag => {
        if (isString(diag.messageText)) return diag;
        const repopulatedChain = convertOrRepopulateDiagnosticMessageChain(diag.messageText, diag.file, newProgram, chain => chain.repopulateInfo?.());
        return repopulatedChain === diag.messageText ?
            diag :
            { ...diag, messageText: repopulatedChain };
    });
}

function convertOrRepopulateDiagnosticMessageChain<T extends DiagnosticMessageChain | ReusableDiagnosticMessageChain>(
    chain: T,
    sourceFile: SourceFile | undefined,
    newProgram: Program,
    repopulateInfo: (chain: T) => RepopulateDiagnosticChainInfo | undefined,
): DiagnosticMessageChain {
    const info = repopulateInfo(chain);
    if (info) {
        return {
            ...createModuleNotFoundChain(sourceFile!, newProgram, info.moduleReference, info.mode, info.packageName || info.moduleReference),
            next: convertOrRepopulateDiagnosticMessageChainArray(chain.next as T[], sourceFile, newProgram, repopulateInfo),
        };
    }
    const next = convertOrRepopulateDiagnosticMessageChainArray(chain.next as T[], sourceFile, newProgram, repopulateInfo);
    return next === chain.next ? chain as DiagnosticMessageChain : { ...chain as DiagnosticMessageChain, next };
}

function convertOrRepopulateDiagnosticMessageChainArray<T extends DiagnosticMessageChain | ReusableDiagnosticMessageChain>(
    array: T[] | undefined,
    sourceFile: SourceFile | undefined,
    newProgram: Program,
    repopulateInfo: (chain: T) => RepopulateDiagnosticChainInfo | undefined,
): DiagnosticMessageChain[] | undefined {
    return sameMap(array, chain => convertOrRepopulateDiagnosticMessageChain(chain, sourceFile, newProgram, repopulateInfo));
}

function convertToDiagnostics(
    diagnostics: readonly ReusableDiagnostic[],
    diagnosticFilePath: Path,
    newProgram: Program,
): readonly Diagnostic[] {
    if (!diagnostics.length) return emptyArray;
    let buildInfoDirectory: string | undefined;
    return diagnostics.map(diagnostic => {
        const result: Diagnostic = convertToDiagnosticRelatedInformation(diagnostic, diagnosticFilePath, newProgram, toPathInBuildInfoDirectory);
        result.reportsUnnecessary = diagnostic.reportsUnnecessary;
        result.reportsDeprecated = diagnostic.reportDeprecated;
        result.source = diagnostic.source;
        result.skippedOn = diagnostic.skippedOn;
        const { relatedInformation } = diagnostic;
        result.relatedInformation = relatedInformation ?
            relatedInformation.length ?
                relatedInformation.map(r => convertToDiagnosticRelatedInformation(r, diagnosticFilePath, newProgram, toPathInBuildInfoDirectory)) :
                [] :
            undefined;
        return result;
    });

    function toPathInBuildInfoDirectory(path: string) {
        buildInfoDirectory ??= getDirectoryPath(getNormalizedAbsolutePath(getTsBuildInfoEmitOutputFilePath(newProgram.getCompilerOptions())!, newProgram.getCurrentDirectory()));
        return toPath(path, buildInfoDirectory, newProgram.getCanonicalFileName);
    }
}

function convertToDiagnosticRelatedInformation(
    diagnostic: ReusableDiagnosticRelatedInformation,
    diagnosticFilePath: Path,
    newProgram: Program,
    toPath: (path: string) => Path,
): DiagnosticRelatedInformation {
    const { file } = diagnostic;
    const sourceFile = file !== false ?
        newProgram.getSourceFileByPath(file ? toPath(file) : diagnosticFilePath) :
        undefined;
    return {
        ...diagnostic,
        file: sourceFile,
        messageText: isString(diagnostic.messageText) ?
            diagnostic.messageText :
            convertOrRepopulateDiagnosticMessageChain(diagnostic.messageText, sourceFile, newProgram, chain => (chain as ReusableRepopulateModuleNotFoundChain).info),
    };
}

/**
 * Releases program and other related not needed properties
 */
function releaseCache(state: BuilderProgramState) {
    BuilderState.releaseCache(state);
    state.program = undefined;
}

/**
 * Verifies that source file is ok to be used in calls that arent handled by next
 */
function assertSourceFileOkWithoutNextAffectedCall(state: BuilderProgramState, sourceFile: SourceFile | undefined) {
    Debug.assert(!sourceFile || !state.affectedFiles || state.affectedFiles[state.affectedFilesIndex! - 1] !== sourceFile || !state.semanticDiagnosticsPerFile.has(sourceFile.resolvedPath));
}

/**
 * This function returns the next affected file to be processed.
 * Note that until doneAffected is called it would keep reporting same result
 * This is to allow the callers to be able to actually remove affected file only when the operation is complete
 * eg. if during diagnostics check cancellation token ends up cancelling the request, the affected file should be retained
 */
function getNextAffectedFile(
    state: BuilderProgramStateWithDefinedProgram,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
): SourceFile | Program | undefined {
    while (true) {
        const { affectedFiles } = state;
        if (affectedFiles) {
            const seenAffectedFiles = state.seenAffectedFiles!;
            let affectedFilesIndex = state.affectedFilesIndex!; // TODO: GH#18217
            while (affectedFilesIndex < affectedFiles.length) {
                const affectedFile = affectedFiles[affectedFilesIndex];
                if (!seenAffectedFiles.has(affectedFile.resolvedPath)) {
                    // Set the next affected file as seen and remove the cached semantic diagnostics
                    state.affectedFilesIndex = affectedFilesIndex;
                    addToAffectedFilesPendingEmit(
                        state,
                        affectedFile.resolvedPath,
                        getBuilderFileEmit(state.compilerOptions),
                    );
                    handleDtsMayChangeOfAffectedFile(
                        state,
                        affectedFile,
                        cancellationToken,
                        host,
                    );
                    return affectedFile;
                }
                affectedFilesIndex++;
            }

            // Remove the changed file from the change set
            state.changedFilesSet.delete(state.currentChangedFilePath!);
            state.currentChangedFilePath = undefined;
            // Commit the changes in file signature
            state.oldSignatures?.clear();
            state.affectedFiles = undefined;
        }

        // Get next changed file
        const nextKey = state.changedFilesSet.keys().next();
        if (nextKey.done) {
            // Done
            return undefined;
        }

        // With --out or --outFile all outputs go into single file
        // so operations are performed directly on program, return program
        const compilerOptions = state.program.getCompilerOptions();
        if (compilerOptions.outFile) return state.program;

        // Get next batch of affected files
        state.affectedFiles = BuilderState.getFilesAffectedByWithOldState(
            state,
            state.program,
            nextKey.value,
            cancellationToken,
            host,
        );
        state.currentChangedFilePath = nextKey.value;
        state.affectedFilesIndex = 0;
        if (!state.seenAffectedFiles) state.seenAffectedFiles = new Set();
    }
}

function clearAffectedFilesPendingEmit(state: BuilderProgramState, emitOnlyDtsFiles: boolean | undefined) {
    if (!state.affectedFilesPendingEmit?.size && !state.programEmitPending) return;
    if (!emitOnlyDtsFiles) {
        state.affectedFilesPendingEmit = undefined;
        state.programEmitPending = undefined;
    }
    state.affectedFilesPendingEmit?.forEach((emitKind, path) => {
        // Mark the files as pending only if they are pending on js files, remove the dts emit pending flag
        const pending = emitKind & BuilderFileEmit.AllJs;
        if (!pending) state.affectedFilesPendingEmit!.delete(path);
        else state.affectedFilesPendingEmit!.set(path, pending);
    });
    // Mark the program as pending only if its pending on js files, remove the dts emit pending flag
    if (state.programEmitPending) {
        const pending = state.programEmitPending & BuilderFileEmit.AllJs;
        if (!pending) state.programEmitPending = undefined;
        else state.programEmitPending = pending;
    }
}

/**
 * Returns next file to be emitted from files that retrieved semantic diagnostics but did not emit yet
 */
function getNextAffectedFilePendingEmit(
    state: BuilderProgramStateWithDefinedProgram,
    emitOnlyDtsFiles: boolean | undefined,
) {
    if (!state.affectedFilesPendingEmit?.size) return undefined;
    return forEachEntry(state.affectedFilesPendingEmit, (emitKind, path) => {
        const affectedFile = state.program.getSourceFileByPath(path);
        if (!affectedFile || !sourceFileMayBeEmitted(affectedFile, state.program)) {
            state.affectedFilesPendingEmit!.delete(path);
            return undefined;
        }
        const seenKind = state.seenEmittedFiles?.get(affectedFile.resolvedPath);
        let pendingKind = getPendingEmitKind(emitKind, seenKind);
        if (emitOnlyDtsFiles) pendingKind = pendingKind & BuilderFileEmit.AllDts;
        if (pendingKind) return { affectedFile, emitKind: pendingKind };
    });
}

function getNextPendingEmitDiagnosticsFile(state: BuilderProgramStateWithDefinedProgram) {
    if (!state.emitDiagnosticsPerFile?.size) return undefined;
    return forEachEntry(state.emitDiagnosticsPerFile, (diagnostics, path) => {
        const affectedFile = state.program.getSourceFileByPath(path);
        if (!affectedFile || !sourceFileMayBeEmitted(affectedFile, state.program)) {
            state.emitDiagnosticsPerFile!.delete(path);
            return undefined;
        }
        const seenKind = state.seenEmittedFiles?.get(affectedFile.resolvedPath) || BuilderFileEmit.None;
        if (!(seenKind & BuilderFileEmit.AllDts)) return { affectedFile, diagnostics, seenKind };
    });
}

function removeDiagnosticsOfLibraryFiles(state: BuilderProgramStateWithDefinedProgram) {
    if (!state.cleanedDiagnosticsOfLibFiles) {
        state.cleanedDiagnosticsOfLibFiles = true;
        const options = state.program.getCompilerOptions();
        forEach(state.program.getSourceFiles(), f =>
            state.program.isSourceFileDefaultLibrary(f) &&
            !skipTypeCheckingIgnoringNoCheck(f, options, state.program) &&
            removeSemanticDiagnosticsOf(state, f.resolvedPath));
    }
}

/**
 *  Handles semantic diagnostics and dts emit for affectedFile and files, that are referencing modules that export entities from affected file
 *  This is because even though js emit doesnt change, dts emit / type used can change resulting in need for dts emit and js change
 */
function handleDtsMayChangeOfAffectedFile(
    state: BuilderProgramStateWithDefinedProgram,
    affectedFile: SourceFile,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
) {
    removeSemanticDiagnosticsOf(state, affectedFile.resolvedPath);

    // If affected files is everything except default library, then nothing more to do
    if (state.allFilesExcludingDefaultLibraryFile === state.affectedFiles) {
        removeDiagnosticsOfLibraryFiles(state);
        // When a change affects the global scope, all files are considered to be affected without updating their signature
        // That means when affected file is handled, its signature can be out of date
        // To avoid this, ensure that we update the signature for any affected file in this scenario.
        BuilderState.updateShapeSignature(
            state,
            state.program,
            affectedFile,
            cancellationToken,
            host,
        );
        return;
    }
    if (state.compilerOptions.assumeChangesOnlyAffectDirectDependencies) return;
    handleDtsMayChangeOfReferencingExportOfAffectedFile(
        state,
        affectedFile,
        cancellationToken,
        host,
    );
}

/**
 * Handle the dts may change, so they need to be added to pending emit if dts emit is enabled,
 * Also we need to make sure signature is updated for these files
 */
function handleDtsMayChangeOf(
    state: BuilderProgramStateWithDefinedProgram,
    path: Path,
    invalidateJsFiles: boolean,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
): void {
    removeSemanticDiagnosticsOf(state, path);

    if (!state.changedFilesSet.has(path)) {
        const sourceFile = state.program.getSourceFileByPath(path);
        if (sourceFile) {
            // Even though the js emit doesnt change and we are already handling dts emit and semantic diagnostics
            // we need to update the signature to reflect correctness of the signature(which is output d.ts emit) of this file
            // This ensures that we dont later during incremental builds considering wrong signature.
            // Eg where this also is needed to ensure that .tsbuildinfo generated by incremental build should be same as if it was first fresh build
            // But we avoid expensive full shape computation, as using file version as shape is enough for correctness.
            BuilderState.updateShapeSignature(
                state,
                state.program,
                sourceFile,
                cancellationToken,
                host,
                /*useFileVersionAsSignature*/ true,
            );
            // If not dts emit, nothing more to do
            if (invalidateJsFiles) {
                addToAffectedFilesPendingEmit(
                    state,
                    path,
                    getBuilderFileEmit(state.compilerOptions),
                );
            }
            else if (getEmitDeclarations(state.compilerOptions)) {
                addToAffectedFilesPendingEmit(
                    state,
                    path,
                    state.compilerOptions.declarationMap ? BuilderFileEmit.AllDts : BuilderFileEmit.Dts,
                );
            }
        }
    }
}

/**
 * Removes semantic diagnostics for path and
 * returns true if there are no more semantic diagnostics from the old state
 */
function removeSemanticDiagnosticsOf(state: BuilderProgramState, path: Path) {
    if (!state.semanticDiagnosticsFromOldState) {
        return true;
    }
    state.semanticDiagnosticsFromOldState.delete(path);
    state.semanticDiagnosticsPerFile.delete(path);
    return !state.semanticDiagnosticsFromOldState.size;
}

function isChangedSignature(state: BuilderProgramState, path: Path) {
    const oldSignature = Debug.checkDefined(state.oldSignatures).get(path) || undefined;
    const newSignature = Debug.checkDefined(state.fileInfos.get(path)).signature;
    return newSignature !== oldSignature;
}

function handleDtsMayChangeOfGlobalScope(
    state: BuilderProgramStateWithDefinedProgram,
    filePath: Path,
    invalidateJsFiles: boolean,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
): boolean {
    if (!state.fileInfos.get(filePath)?.affectsGlobalScope) return false;
    // Every file needs to be handled
    BuilderState.getAllFilesExcludingDefaultLibraryFile(
        state,
        state.program,
        /*firstSourceFile*/ undefined,
    ).forEach(file =>
        handleDtsMayChangeOf(
            state,
            file.resolvedPath,
            invalidateJsFiles,
            cancellationToken,
            host,
        )
    );
    removeDiagnosticsOfLibraryFiles(state);
    return true;
}

/**
 * Iterate on referencing modules that export entities from affected file and delete diagnostics and add pending emit
 */
function handleDtsMayChangeOfReferencingExportOfAffectedFile(
    state: BuilderProgramStateWithDefinedProgram,
    affectedFile: SourceFile,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
) {
    // If there was change in signature (dts output) for the changed file,
    // then only we need to handle pending file emit
    if (!state.referencedMap || !state.changedFilesSet.has(affectedFile.resolvedPath)) return;
    if (!isChangedSignature(state, affectedFile.resolvedPath)) return;

    // Since isolated modules dont change js files, files affected by change in signature is itself
    // But we need to cleanup semantic diagnostics and queue dts emit for affected files
    if (getIsolatedModules(state.compilerOptions)) {
        const seenFileNamesMap = new Map<Path, true>();
        seenFileNamesMap.set(affectedFile.resolvedPath, true);
        const queue = BuilderState.getReferencedByPaths(state, affectedFile.resolvedPath);
        while (queue.length > 0) {
            const currentPath = queue.pop()!;
            if (!seenFileNamesMap.has(currentPath)) {
                seenFileNamesMap.set(currentPath, true);
                if (
                    handleDtsMayChangeOfGlobalScope(
                        state,
                        currentPath,
                        /*invalidateJsFiles*/ false,
                        cancellationToken,
                        host,
                    )
                ) return;
                handleDtsMayChangeOf(state, currentPath, /*invalidateJsFiles*/ false, cancellationToken, host);
                if (isChangedSignature(state, currentPath)) {
                    const currentSourceFile = state.program.getSourceFileByPath(currentPath)!;
                    queue.push(...BuilderState.getReferencedByPaths(state, currentSourceFile.resolvedPath));
                }
            }
        }
    }

    const seenFileAndExportsOfFile = new Set<string>();
    // If exported const enum, we need to ensure that js files are emitted as well since the const enum value changed
    const invalidateJsFiles = !!affectedFile.symbol?.exports && !!forEachEntry(
        affectedFile.symbol.exports,
        exported => {
            if ((exported.flags & SymbolFlags.ConstEnum) !== 0) return true;
            const aliased = skipAlias(exported, state.program.getTypeChecker());
            if (aliased === exported) return false;
            return (aliased.flags & SymbolFlags.ConstEnum) !== 0 &&
                some(aliased.declarations, d => getSourceFileOfNode(d) === affectedFile);
        },
    );
    // Go through files that reference affected file and handle dts emit and semantic diagnostics for them and their references
    state.referencedMap.getKeys(affectedFile.resolvedPath)?.forEach(exportedFromPath => {
        if (handleDtsMayChangeOfGlobalScope(state, exportedFromPath, invalidateJsFiles, cancellationToken, host)) return true;
        const references = state.referencedMap!.getKeys(exportedFromPath);
        return references && forEachKey(references, filePath =>
            handleDtsMayChangeOfFileAndExportsOfFile(
                state,
                filePath,
                invalidateJsFiles,
                seenFileAndExportsOfFile,
                cancellationToken,
                host,
            ));
    });
}

/**
 * handle dts and semantic diagnostics on file and iterate on anything that exports this file
 * return true when all work is done and we can exit handling dts emit and semantic diagnostics
 */
function handleDtsMayChangeOfFileAndExportsOfFile(
    state: BuilderProgramStateWithDefinedProgram,
    filePath: Path,
    invalidateJsFiles: boolean,
    seenFileAndExportsOfFile: Set<string>,
    cancellationToken: CancellationToken | undefined,
    host: BuilderProgramHost,
): boolean | undefined {
    if (!tryAddToSet(seenFileAndExportsOfFile, filePath)) return undefined;

    if (handleDtsMayChangeOfGlobalScope(state, filePath, invalidateJsFiles, cancellationToken, host)) return true;
    handleDtsMayChangeOf(state, filePath, invalidateJsFiles, cancellationToken, host);

    // Remove the diagnostics of files that import this file and handle all its exports too
    state.referencedMap!.getKeys(filePath)?.forEach(referencingFilePath =>
        handleDtsMayChangeOfFileAndExportsOfFile(
            state,
            referencingFilePath,
            invalidateJsFiles,
            seenFileAndExportsOfFile,
            cancellationToken,
            host,
        )
    );
    return undefined;
}

/**
 * Gets semantic diagnostics for the file which are
 * bindAndCheckDiagnostics (from cache) and program diagnostics
 */
function getSemanticDiagnosticsOfFile(
    state: BuilderProgramStateWithDefinedProgram,
    sourceFile: SourceFile,
    cancellationToken: CancellationToken | undefined,
    semanticDiagnosticsPerFile?: BuilderProgramState["semanticDiagnosticsPerFile"],
): readonly Diagnostic[] {
    if (state.compilerOptions.noCheck) return emptyArray;
    return concatenate(
        getBinderAndCheckerDiagnosticsOfFile(state, sourceFile, cancellationToken, semanticDiagnosticsPerFile),
        state.program.getProgramDiagnostics(sourceFile),
    );
}

/**
 * Gets the binder and checker diagnostics either from cache if present, or otherwise from program and caches it
 * Note that it is assumed that when asked about binder and checker diagnostics, the file has been taken out of affected files/changed file set
 */
function getBinderAndCheckerDiagnosticsOfFile(
    state: BuilderProgramStateWithDefinedProgram,
    sourceFile: SourceFile,
    cancellationToken: CancellationToken | undefined,
    semanticDiagnosticsPerFile: BuilderProgramState["semanticDiagnosticsPerFile"] | undefined,
): readonly Diagnostic[] {
    semanticDiagnosticsPerFile ??= state.semanticDiagnosticsPerFile;
    const path = sourceFile.resolvedPath;
    const cachedDiagnostics = semanticDiagnosticsPerFile.get(path);
    // Report the bind and check diagnostics from the cache if we already have those diagnostics present
    if (cachedDiagnostics) {
        return filterSemanticDiagnostics(cachedDiagnostics, state.compilerOptions);
    }

    // Diagnostics werent cached, get them from program, and cache the result
    const diagnostics = state.program.getBindAndCheckDiagnostics(sourceFile, cancellationToken);
    semanticDiagnosticsPerFile.set(path, diagnostics);
    state.buildInfoEmitPending = true;
    return filterSemanticDiagnostics(diagnostics, state.compilerOptions);
}

/** @internal */
export type IncrementalBuildInfoFileId = number & { __incrementalBuildInfoFileIdBrand: any; };
/** @internal */
export type IncrementalBuildInfoFileIdListId = number & { __incrementalBuildInfoFileIdListIdBrand: any; };
/** @internal */
export type IncrementalBuildInfoDiagnosticOfFile = [fileId: IncrementalBuildInfoFileId, diagnostics: readonly ReusableDiagnostic[]];
/** @internal */
export type IncrementalBuildInfoDiagnostic =
    | IncrementalBuildInfoFileId // File is not in changedSet and still doesnt have cached diagnostics
    | IncrementalBuildInfoDiagnosticOfFile; // Diagnostics for file
/** @internal */
export type IncrementalBuildInfoEmitDiagnostic = IncrementalBuildInfoDiagnosticOfFile; // Diagnostics for the file

/**
 * fileId if pending emit is same as what compilerOptions suggest
 * [fileId] if pending emit is only dts file emit
 * [fileId, emitKind] if any other type emit is pending
 *
 * @internal
 */
export type IncrementalBuildInfoFilePendingEmit = IncrementalBuildInfoFileId | [fileId: IncrementalBuildInfoFileId] | [fileId: IncrementalBuildInfoFileId, emitKind: BuilderFileEmit];
/** @internal */
export type IncrementalBuildInfoReferencedMap = [fileId: IncrementalBuildInfoFileId, fileIdListId: IncrementalBuildInfoFileIdListId][];
/** @internal */
export type IncrementalMultiFileEmitBuildInfoBuilderStateFileInfo = Omit<BuilderState.FileInfo, "signature"> & {
    /**
     * Signature is
     * - undefined if FileInfo.version === FileInfo.signature
     * - false if FileInfo has signature as undefined (not calculated)
     * - string actual signature
     */
    signature: string | false | undefined;
};
/**
 * [fileId, signature] if different from file's signature
 * fileId if file wasnt emitted
 *
 * @internal
 */
export type IncrementalBuildInfoEmitSignature = IncrementalBuildInfoFileId | [fileId: IncrementalBuildInfoFileId, signature: EmitSignature | []];
/**
 * IncrementalMultiFileEmitBuildInfoFileInfo is string if FileInfo.version === FileInfo.signature && !FileInfo.affectsGlobalScope otherwise encoded FileInfo
 *
 * @internal
 */
export type IncrementalMultiFileEmitBuildInfoFileInfo = string | IncrementalMultiFileEmitBuildInfoBuilderStateFileInfo;
/** @internal */
export type IncrementalBuildInfoRootStartEnd = [start: IncrementalBuildInfoFileId, end: IncrementalBuildInfoFileId];
/**
 * Either start and end of FileId for consecutive fileIds to be included as root or single fileId that is root
 * @internal
 */
export type IncrementalBuildInfoRoot = IncrementalBuildInfoRootStartEnd | IncrementalBuildInfoFileId;
/** @internal */
export type IncrementalBuildInfoResolvedRoot = [resolved: IncrementalBuildInfoFileId, root: IncrementalBuildInfoFileId];

/** @internal */
export interface IncrementalBuildInfoBase extends BuildInfo {
    fileNames: readonly string[];
    root: readonly IncrementalBuildInfoRoot[];
    resolvedRoot: readonly IncrementalBuildInfoResolvedRoot[] | undefined;
    options: CompilerOptions | undefined;
    semanticDiagnosticsPerFile: IncrementalBuildInfoDiagnostic[] | undefined;
    emitDiagnosticsPerFile: IncrementalBuildInfoEmitDiagnostic[] | undefined;
    // Because this is only output file in the program, we dont need fileId to deduplicate name
    latestChangedDtsFile?: string | undefined;
    errors: true | undefined;
    checkPending: true | undefined;
}

/** @internal */
export interface IncrementalMultiFileEmitBuildInfo extends IncrementalBuildInfoBase {
    fileInfos: readonly IncrementalMultiFileEmitBuildInfoFileInfo[];
    fileIdsList: readonly (readonly IncrementalBuildInfoFileId[])[] | undefined;
    referencedMap: IncrementalBuildInfoReferencedMap | undefined;
    affectedFilesPendingEmit: IncrementalBuildInfoFilePendingEmit[] | undefined;
    emitSignatures: readonly IncrementalBuildInfoEmitSignature[] | undefined;
}
/**
 * IncrementalBundleEmitBuildInfoFileInfo is string if !FileInfo.impliedFormat otherwise encoded FileInfo
 *
 * @internal
 */
export type IncrementalBundleEmitBuildInfoFileInfo = string | BuilderState.FileInfo;
/**
 * false if it is the emit corresponding to compilerOptions
 * value otherwise
 *
 * @internal
 */
export type IncrementalBuildInfoBundlePendingEmit = BuilderFileEmit | false;
/** @internal */
export interface IncrementalBundleEmitBuildInfo extends IncrementalBuildInfoBase {
    fileInfos: readonly IncrementalBundleEmitBuildInfoFileInfo[];
    outSignature: EmitSignature | undefined;
    pendingEmit: IncrementalBuildInfoBundlePendingEmit | undefined;
}

/** @internal */
export type IncrementalBuildInfo = IncrementalMultiFileEmitBuildInfo | IncrementalBundleEmitBuildInfo;

/** @internal */
export function isIncrementalBundleEmitBuildInfo(info: IncrementalBuildInfo): info is IncrementalBundleEmitBuildInfo {
    return !!info.options?.outFile;
}

/** @internal */
export function isIncrementalBuildInfo(info: BuildInfo): info is IncrementalBuildInfo {
    return !!(info as IncrementalBuildInfo).fileNames;
}

/** @internal */
export interface NonIncrementalBuildInfo extends BuildInfo {
    root: readonly string[];
    errors: true | undefined;
    checkPending: true | undefined;
}

/** @internal */
export function isNonIncrementalBuildInfo(info: BuildInfo): info is NonIncrementalBuildInfo {
    return !isIncrementalBuildInfo(info) && !!(info as NonIncrementalBuildInfo).root;
}

function ensureHasErrorsForState(state: BuilderProgramStateWithDefinedProgram) {
    if (state.hasErrors !== undefined) return;
    if (isIncrementalCompilation(state.compilerOptions)) {
        // Because semantic diagnostics are recorded as is we dont need to get them from program
        state.hasErrors = !some(state.program.getSourceFiles(), f => {
            const bindAndCheckDiagnostics = state.semanticDiagnosticsPerFile.get(f.resolvedPath);
            return bindAndCheckDiagnostics === undefined || // Missing semantic diagnostics in cache will be encoded in buildInfo
                !!bindAndCheckDiagnostics.length || // cached semantic diagnostics will be encoded in buildInfo
                !!state.emitDiagnosticsPerFile?.get(f.resolvedPath)?.length; // emit diagnostics will be encoded in buildInfo;
        }) && (
            hasSyntaxOrGlobalErrors(state) ||
            some(state.program.getSourceFiles(), f => !!state.program.getProgramDiagnostics(f).length)
        );
    }
    else {
        state.hasErrors = some(state.program.getSourceFiles(), f => {
            const bindAndCheckDiagnostics = state.semanticDiagnosticsPerFile.get(f.resolvedPath);
            return !!bindAndCheckDiagnostics?.length || // If has semantic diagnostics
                !!state.emitDiagnosticsPerFile?.get(f.resolvedPath)?.length; // emit diagnostics will be encoded in buildInfo;
        }) ||
            hasSyntaxOrGlobalErrors(state);
    }
}

function hasSyntaxOrGlobalErrors(state: BuilderProgramStateWithDefinedProgram) {
    return !!state.program.getConfigFileParsingDiagnostics().length ||
        !!state.program.getSyntacticDiagnostics().length ||
        !!state.program.getOptionsDiagnostics().length ||
        !!state.program.getGlobalDiagnostics().length;
}

function getBuildInfoEmitPending(state: BuilderProgramStateWithDefinedProgram) {
    ensureHasErrorsForState(state);
    return state.buildInfoEmitPending ??= !!state.hasErrorsFromOldState !== !!state.hasErrors;
}

/**
 * Gets the program information to be emitted in buildInfo so that we can use it to create new program
 */
function getBuildInfo(state: BuilderProgramStateWithDefinedProgram): BuildInfo {
    const currentDirectory = state.program.getCurrentDirectory();
    const buildInfoDirectory = getDirectoryPath(getNormalizedAbsolutePath(getTsBuildInfoEmitOutputFilePath(state.compilerOptions)!, currentDirectory));
    // Convert the file name to Path here if we set the fileName instead to optimize multiple d.ts file emits and having to compute Canonical path
    const latestChangedDtsFile = state.latestChangedDtsFile ? relativeToBuildInfoEnsuringAbsolutePath(state.latestChangedDtsFile) : undefined;
    const fileNames: string[] = [];
    const fileNameToFileId = new Map<string, IncrementalBuildInfoFileId>();
    const rootFileNames = new Set(state.program.getRootFileNames().map(f => toPath(f, currentDirectory, state.program.getCanonicalFileName)));
    ensureHasErrorsForState(state);
    if (!isIncrementalCompilation(state.compilerOptions)) {
        const buildInfo: NonIncrementalBuildInfo = {
            root: arrayFrom(rootFileNames, r => relativeToBuildInfo(r)),
            errors: state.hasErrors ? true : undefined,
            checkPending: state.checkPending,
            version,
        };
        return buildInfo;
    }

    const root: IncrementalBuildInfoRoot[] = [];
    if (state.compilerOptions.outFile) {
        // Copy all fileInfo, version and impliedFormat
        // Affects global scope and signature doesnt matter because with --out they arent calculated or needed to determine upto date ness
        const fileInfos = arrayFrom(state.fileInfos.entries(), ([key, value]): IncrementalBundleEmitBuildInfoFileInfo => {
            // Ensure fileId
            const fileId = toFileId(key);
            tryAddRoot(key, fileId);
            return value.impliedFormat ?
                { version: value.version, impliedFormat: value.impliedFormat, signature: undefined, affectsGlobalScope: undefined } :
                value.version;
        });
        const buildInfo: IncrementalBundleEmitBuildInfo = {
            fileNames,
            fileInfos,
            root,
            resolvedRoot: toResolvedRoot(),
            options: toIncrementalBuildInfoCompilerOptions(state.compilerOptions),
            semanticDiagnosticsPerFile: toIncrementalBuildInfoDiagnostics(),
            emitDiagnosticsPerFile: toIncrementalBuildInfoEmitDiagnostics(),
            outSignature: state.outSignature,
            latestChangedDtsFile,
            pendingEmit: !state.programEmitPending ?
                undefined : // Pending is undefined or None is encoded as undefined
                state.programEmitPending === getBuilderFileEmit(state.compilerOptions) ?
                false : // Pending emit is same as deteremined by compilerOptions
                state.programEmitPending, // Actual value
            errors: state.hasErrors ? true : undefined,
            checkPending: state.checkPending,
            version,
        };
        return buildInfo;
    }

    let fileIdsList: (readonly IncrementalBuildInfoFileId[])[] | undefined;
    let fileNamesToFileIdListId: Map<string, IncrementalBuildInfoFileIdListId> | undefined;
    let emitSignatures: IncrementalBuildInfoEmitSignature[] | undefined;
    const fileInfos = arrayFrom(state.fileInfos.entries(), ([key, value]): IncrementalMultiFileEmitBuildInfoFileInfo => {
        // Ensure fileId
        const fileId = toFileId(key);
        tryAddRoot(key, fileId);
        Debug.assert(fileNames[fileId - 1] === relativeToBuildInfo(key));
        const oldSignature = state.oldSignatures?.get(key);
        const actualSignature = oldSignature !== undefined ? oldSignature || undefined : value.signature;
        if (state.compilerOptions.composite) {
            const file = state.program.getSourceFileByPath(key)!;
            if (!isJsonSourceFile(file) && sourceFileMayBeEmitted(file, state.program)) {
                const emitSignature = state.emitSignatures?.get(key);
                if (emitSignature !== actualSignature) {
                    emitSignatures = append(
                        emitSignatures,
                        emitSignature === undefined ?
                            fileId : // There is no emit, encode as false
                            // fileId, signature: emptyArray if signature only differs in dtsMap option than our own compilerOptions otherwise EmitSignature
                            [fileId, !isString(emitSignature) && emitSignature[0] === actualSignature ? emptyArray as [] : emitSignature],
                    );
                }
            }
        }
        return value.version === actualSignature ?
            value.affectsGlobalScope || value.impliedFormat ?
                // If file version is same as signature, dont serialize signature
                { version: value.version, signature: undefined, affectsGlobalScope: value.affectsGlobalScope, impliedFormat: value.impliedFormat } :
                // If file info only contains version and signature and both are same we can just write string
                value.version :
            actualSignature !== undefined ? // If signature is not same as version, encode signature in the fileInfo
            oldSignature === undefined ?
                // If we havent computed signature, use fileInfo as is
                value :
                // Serialize fileInfo with new updated signature
                { version: value.version, signature: actualSignature, affectsGlobalScope: value.affectsGlobalScope, impliedFormat: value.impliedFormat } :
            // Signature of the FileInfo is undefined, serialize it as false
            { version: value.version, signature: false, affectsGlobalScope: value.affectsGlobalScope, impliedFormat: value.impliedFormat };
    });

    let referencedMap: IncrementalBuildInfoReferencedMap | undefined;
    if (state.referencedMap?.size()) {
        referencedMap = arrayFrom(state.referencedMap.keys()).sort(compareStringsCaseSensitive).map(key => [
            toFileId(key),
            toFileIdListId(state.referencedMap!.getValues(key)!),
        ]);
    }

    const semanticDiagnosticsPerFile = toIncrementalBuildInfoDiagnostics();
    let affectedFilesPendingEmit: IncrementalBuildInfoFilePendingEmit[] | undefined;
    if (state.affectedFilesPendingEmit?.size) {
        const fullEmitForOptions = getBuilderFileEmit(state.compilerOptions);
        const seenFiles = new Set<Path>();
        for (const path of arrayFrom(state.affectedFilesPendingEmit.keys()).sort(compareStringsCaseSensitive)) {
            if (tryAddToSet(seenFiles, path)) {
                const file = state.program.getSourceFileByPath(path);
                if (!file || !sourceFileMayBeEmitted(file, state.program)) continue;
                const fileId = toFileId(path), pendingEmit = state.affectedFilesPendingEmit.get(path)!;
                affectedFilesPendingEmit = append(
                    affectedFilesPendingEmit,
                    pendingEmit === fullEmitForOptions ?
                        fileId : // Pending full emit per options
                        pendingEmit === BuilderFileEmit.Dts ?
                        [fileId] : // Pending on Dts only
                        [fileId, pendingEmit], // Anything else
                );
            }
        }
    }

    const buildInfo: IncrementalMultiFileEmitBuildInfo = {
        fileNames,
        fileIdsList,
        fileInfos,
        root,
        resolvedRoot: toResolvedRoot(),
        options: toIncrementalBuildInfoCompilerOptions(state.compilerOptions),
        referencedMap,
        semanticDiagnosticsPerFile,
        emitDiagnosticsPerFile: toIncrementalBuildInfoEmitDiagnostics(),
        affectedFilesPendingEmit,
        emitSignatures,
        latestChangedDtsFile,
        errors: state.hasErrors ? true : undefined,
        checkPending: state.checkPending,
        version,
    };
    return buildInfo;

    function relativeToBuildInfoEnsuringAbsolutePath(path: string) {
        return relativeToBuildInfo(getNormalizedAbsolutePath(path, currentDirectory));
    }

    function relativeToBuildInfo(path: string) {
        return ensurePathIsNonModuleName(getRelativePathFromDirectory(buildInfoDirectory, path, state.program.getCanonicalFileName));
    }

    function toFileId(path: Path): IncrementalBuildInfoFileId {
        let fileId = fileNameToFileId.get(path);
        if (fileId === undefined) {
            fileNames.push(relativeToBuildInfo(path));
            fileNameToFileId.set(path, fileId = fileNames.length as IncrementalBuildInfoFileId);
        }
        return fileId;
    }

    function toFileIdListId(set: ReadonlySet<Path>): IncrementalBuildInfoFileIdListId {
        const fileIds = arrayFrom(set.keys(), toFileId).sort(compareValues);
        const key = fileIds.join();
        let fileIdListId = fileNamesToFileIdListId?.get(key);
        if (fileIdListId === undefined) {
            fileIdsList = append(fileIdsList, fileIds);
            (fileNamesToFileIdListId ??= new Map()).set(key, fileIdListId = fileIdsList.length as IncrementalBuildInfoFileIdListId);
        }
        return fileIdListId;
    }

    function tryAddRoot(path: Path, fileId: IncrementalBuildInfoFileId) {
        const file = state.program.getSourceFile(path)!;
        if (!state.program.getFileIncludeReasons().get(file.path)!.some(r => r.kind === FileIncludeKind.RootFile)) return;
        // First fileId as is
        if (!root.length) return root.push(fileId);
        const last = root[root.length - 1];
        const isLastStartEnd = isArray(last);
        // If its [..., last = [start, end = fileId - 1]], update last to [start, fileId]
        if (isLastStartEnd && last[1] === fileId - 1) return last[1] = fileId;
        // If its [..., last = [start, end !== fileId - 1]] or [last] or [..., last !== fileId - 1], push the fileId
        if (isLastStartEnd || root.length === 1 || last !== fileId - 1) return root.push(fileId);
        const lastButOne = root[root.length - 2];
        // If [..., lastButOne = [start, end], lastFileId] or [..., lastButOne !== lastFileId - 1, lastFileId], push the fileId
        if (!isNumber(lastButOne) || lastButOne !== last - 1) return root.push(fileId);
        // Convert lastButOne as [lastButOne, fileId]
        root[root.length - 2] = [lastButOne, fileId];
        return root.length = root.length - 1;
    }

    function toResolvedRoot(): IncrementalBuildInfoResolvedRoot[] | undefined {
        let result: IncrementalBuildInfoResolvedRoot[] | undefined;
        rootFileNames.forEach(path => {
            const file = state.program.getSourceFileByPath(path);
            if (file && path !== file.resolvedPath) {
                result = append(result, [toFileId(file.resolvedPath), toFileId(path)]);
            }
        });
        return result;
    }

    /**
     * @param optionKey key of CommandLineOption to use to determine if the option should be serialized in tsbuildinfo
     */
    function toIncrementalBuildInfoCompilerOptions(options: CompilerOptions) {
        let result: CompilerOptions | undefined;
        const { optionsNameMap } = getOptionsNameMap();
        for (const name of getOwnKeys(options).sort(compareStringsCaseSensitive)) {
            const optionInfo = optionsNameMap.get(name.toLowerCase());
            if (optionInfo?.affectsBuildInfo) {
                (result ||= {})[name] = toReusableCompilerOptionValue(
                    optionInfo,
                    options[name] as CompilerOptionsValue,
                );
            }
        }
        return result;
    }

    function toReusableCompilerOptionValue(option: CommandLineOption | undefined, value: CompilerOptionsValue) {
        if (option) {
            Debug.assert(option.type !== "listOrElement");
            if (option.type === "list") {
                const values = value as readonly string[];
                if (option.element.isFilePath && values.length) {
                    return values.map(relativeToBuildInfoEnsuringAbsolutePath);
                }
            }
            else if (option.isFilePath) {
                return relativeToBuildInfoEnsuringAbsolutePath(value as string);
            }
        }
        return value;
    }

    function toIncrementalBuildInfoDiagnostics() {
        let result: IncrementalBuildInfoDiagnostic[] | undefined;
        state.fileInfos.forEach((_value, key) => {
            const value = state.semanticDiagnosticsPerFile.get(key);
            if (!value) {
                result = append(result, toFileId(key));
            }
            else if (value.length) {
                result = append(result, [
                    toFileId(key),
                    toReusableDiagnostic(value, key),
                ]);
            }
        });
        return result;
    }

    function toIncrementalBuildInfoEmitDiagnostics() {
        let result: IncrementalBuildInfoEmitDiagnostic[] | undefined;
        if (!state.emitDiagnosticsPerFile?.size) return result;
        for (const key of arrayFrom(state.emitDiagnosticsPerFile.keys()).sort(compareStringsCaseSensitive)) {
            const value = state.emitDiagnosticsPerFile.get(key)!;
            result = append(result, [
                toFileId(key),
                toReusableDiagnostic(value, key),
            ]);
        }
        return result;
    }

    function toReusableDiagnostic(diagnostics: readonly Diagnostic[], diagnosticFilePath: Path): readonly ReusableDiagnostic[] {
        Debug.assert(!!diagnostics.length);
        return diagnostics.map(diagnostic => {
            const result: ReusableDiagnostic = toReusableDiagnosticRelatedInformation(diagnostic, diagnosticFilePath);
            result.reportsUnnecessary = diagnostic.reportsUnnecessary;
            result.reportDeprecated = diagnostic.reportsDeprecated;
            result.source = diagnostic.source;
            result.skippedOn = diagnostic.skippedOn;
            const { relatedInformation } = diagnostic;
            result.relatedInformation = relatedInformation ?
                relatedInformation.length ?
                    relatedInformation.map(r => toReusableDiagnosticRelatedInformation(r, diagnosticFilePath)) :
                    [] :
                undefined;
            return result;
        });
    }

    function toReusableDiagnosticRelatedInformation(diagnostic: DiagnosticRelatedInformation, diagnosticFilePath: Path): ReusableDiagnosticRelatedInformation {
        const { file } = diagnostic;
        return {
            ...diagnostic,
            file: file ?
                file.resolvedPath === diagnosticFilePath ?
                    undefined :
                    relativeToBuildInfo(file.resolvedPath) :
                false,
            messageText: isString(diagnostic.messageText) ? diagnostic.messageText : toReusableDiagnosticMessageChain(diagnostic.messageText),
        };
    }

    function toReusableDiagnosticMessageChain(chain: DiagnosticMessageChain): ReusableDiagnosticMessageChain {
        if (chain.repopulateInfo) {
            return {
                info: chain.repopulateInfo(),
                next: toReusableDiagnosticMessageChainArray(chain.next),
            };
        }
        const next = toReusableDiagnosticMessageChainArray(chain.next);
        return next === chain.next ? chain : { ...chain, next };
    }

    function toReusableDiagnosticMessageChainArray(array: DiagnosticMessageChain[] | undefined): ReusableDiagnosticMessageChain[] | undefined {
        if (!array) return array;
        return forEach(array, (chain, index) => {
            const reusable = toReusableDiagnosticMessageChain(chain);
            if (chain === reusable) return undefined;
            const result: ReusableDiagnosticMessageChain[] = index > 0 ? array.slice(0, index - 1) : [];
            result.push(reusable);
            for (let i = index + 1; i < array.length; i++) {
                result.push(toReusableDiagnosticMessageChain(array[i]));
            }
            return result;
        }) || array;
    }
}

/** @internal */
export enum BuilderProgramKind {
    SemanticDiagnosticsBuilderProgram,
    EmitAndSemanticDiagnosticsBuilderProgram,
}

/** @internal */
export interface BuilderCreationParameters {
    newProgram: Program;
    host: BuilderProgramHost;
    oldProgram: BuilderProgram | undefined;
    configFileParsingDiagnostics: readonly Diagnostic[];
}

/** @internal */
export function getBuilderCreationParameters(newProgramOrRootNames: Program | readonly string[] | undefined, hostOrOptions: BuilderProgramHost | CompilerOptions | undefined, oldProgramOrHost?: BuilderProgram | CompilerHost, configFileParsingDiagnosticsOrOldProgram?: readonly Diagnostic[] | BuilderProgram, configFileParsingDiagnostics?: readonly Diagnostic[], projectReferences?: readonly ProjectReference[]): BuilderCreationParameters {
    let host: BuilderProgramHost;
    let newProgram: Program;
    let oldProgram: BuilderProgram;
    if (newProgramOrRootNames === undefined) {
        Debug.assert(hostOrOptions === undefined);
        host = oldProgramOrHost as CompilerHost;
        oldProgram = configFileParsingDiagnosticsOrOldProgram as BuilderProgram;
        Debug.assert(!!oldProgram);
        newProgram = oldProgram.getProgram();
    }
    else if (isArray(newProgramOrRootNames)) {
        oldProgram = configFileParsingDiagnosticsOrOldProgram as BuilderProgram;
        newProgram = createProgram({
            rootNames: newProgramOrRootNames,
            options: hostOrOptions as CompilerOptions,
            host: oldProgramOrHost as CompilerHost,
            oldProgram: oldProgram && oldProgram.getProgramOrUndefined(),
            configFileParsingDiagnostics,
            projectReferences,
        });
        host = oldProgramOrHost as CompilerHost;
    }
    else {
        newProgram = newProgramOrRootNames;
        host = hostOrOptions as BuilderProgramHost;
        oldProgram = oldProgramOrHost as BuilderProgram;
        configFileParsingDiagnostics = configFileParsingDiagnosticsOrOldProgram as readonly Diagnostic[];
    }
    return { host, newProgram, oldProgram, configFileParsingDiagnostics: configFileParsingDiagnostics || emptyArray };
}

function getTextHandlingSourceMapForSignature(text: string, data: WriteFileCallbackData | undefined) {
    return data?.sourceMapUrlPos !== undefined ? text.substring(0, data.sourceMapUrlPos) : text;
}

/** @internal */
export function computeSignatureWithDiagnostics(
    program: Program,
    sourceFile: SourceFile,
    text: string,
    host: HostForComputeHash,
    data: WriteFileCallbackData | undefined,
) {
    text = getTextHandlingSourceMapForSignature(text, data);
    let sourceFileDirectory: string | undefined;
    if (data?.diagnostics?.length) {
        text += data.diagnostics.map(diagnostic => `${locationInfo(diagnostic)}${DiagnosticCategory[diagnostic.category]}${diagnostic.code}: ${flattenDiagnosticMessageText(diagnostic.messageText)}`).join("\n");
    }
    return (host.createHash ?? generateDjb2Hash)(text);

    function flattenDiagnosticMessageText(diagnostic: string | DiagnosticMessageChain | undefined): string {
        return isString(diagnostic) ?
            diagnostic :
            diagnostic === undefined ?
            "" :
            !diagnostic.next ?
            diagnostic.messageText :
            diagnostic.messageText + diagnostic.next.map(flattenDiagnosticMessageText).join("\n");
    }

    function locationInfo(diagnostic: DiagnosticWithLocation) {
        if (diagnostic.file.resolvedPath === sourceFile.resolvedPath) return `(${diagnostic.start},${diagnostic.length})`;
        if (sourceFileDirectory === undefined) sourceFileDirectory = getDirectoryPath(sourceFile.resolvedPath);
        return `${
            ensurePathIsNonModuleName(getRelativePathFromDirectory(
                sourceFileDirectory,
                diagnostic.file.resolvedPath,
                program.getCanonicalFileName,
            ))
        }(${diagnostic.start},${diagnostic.length})`;
    }
}

/** @internal */
export function computeSignature(text: string, host: HostForComputeHash, data?: WriteFileCallbackData) {
    return (host.createHash ?? generateDjb2Hash)(getTextHandlingSourceMapForSignature(text, data));
}

/** @internal */
export function createBuilderProgram(
    kind: BuilderProgramKind.SemanticDiagnosticsBuilderProgram,
    builderCreationParameters: BuilderCreationParameters,
): SemanticDiagnosticsBuilderProgram;
/** @internal */
export function createBuilderProgram(
    kind: BuilderProgramKind.EmitAndSemanticDiagnosticsBuilderProgram,
    builderCreationParameters: BuilderCreationParameters,
): EmitAndSemanticDiagnosticsBuilderProgram;
/** @internal */
export function createBuilderProgram(
    kind: BuilderProgramKind,
    { newProgram, host, oldProgram, configFileParsingDiagnostics }: BuilderCreationParameters,
) {
    // Return same program if underlying program doesnt change
    let oldState = oldProgram && oldProgram.state;
    if (oldState && newProgram === oldState.program && configFileParsingDiagnostics === newProgram.getConfigFileParsingDiagnostics()) {
        newProgram = undefined!;
        oldState = undefined;
        return oldProgram;
    }

    const state = createBuilderProgramState(newProgram, oldState);
    newProgram.getBuildInfo = () => getBuildInfo(toBuilderProgramStateWithDefinedProgram(state));

    // To ensure that we arent storing any references to old program or new program without state
    newProgram = undefined!;
    oldProgram = undefined;
    oldState = undefined;

    const builderProgram = createRedirectedBuilderProgram(state, configFileParsingDiagnostics);
    builderProgram.state = state;
    builderProgram.hasChangedEmitSignature = () => !!state.hasChangedEmitSignature;
    builderProgram.getAllDependencies = sourceFile =>
        BuilderState.getAllDependencies(
            state,
            Debug.checkDefined(state.program),
            sourceFile,
        );
    builderProgram.getSemanticDiagnostics = getSemanticDiagnostics;
    builderProgram.emit = emit;
    builderProgram.releaseProgram = () => releaseCache(state);

    if (kind === BuilderProgramKind.SemanticDiagnosticsBuilderProgram) {
        (builderProgram as SemanticDiagnosticsBuilderProgram).getSemanticDiagnosticsOfNextAffectedFile = getSemanticDiagnosticsOfNextAffectedFile;
    }
    else if (kind === BuilderProgramKind.EmitAndSemanticDiagnosticsBuilderProgram) {
        (builderProgram as EmitAndSemanticDiagnosticsBuilderProgram).getSemanticDiagnosticsOfNextAffectedFile = getSemanticDiagnosticsOfNextAffectedFile;
        (builderProgram as EmitAndSemanticDiagnosticsBuilderProgram).emitNextAffectedFile = emitNextAffectedFile;
        builderProgram.emitBuildInfo = emitBuildInfo;
    }
    else {
        notImplemented();
    }
    return builderProgram;

    function emitBuildInfo(
        writeFile: WriteFileCallback | undefined,
        cancellationToken: CancellationToken | undefined,
    ): EmitResult {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        if (getBuildInfoEmitPending(state)) {
            const result = state.program.emitBuildInfo(
                writeFile || maybeBind(host, host.writeFile),
                cancellationToken,
            );
            state.buildInfoEmitPending = false;
            return result;
        }
        return emitSkippedWithNoDiagnostics;
    }

    /**
     * Emits the next affected file's emit result (EmitResult and sourceFiles emitted) or returns undefined if iteration is complete
     * The first of writeFile if provided, writeFile of BuilderProgramHost if provided, writeFile of compiler host
     * in that order would be used to write the files
     */
    function emitNextAffectedFile(
        writeFile: WriteFileCallback | undefined,
        cancellationToken: CancellationToken | undefined,
        emitOnlyDtsFiles: boolean | undefined,
        customTransformers: CustomTransformers | undefined,
    ): AffectedFileResult<EmitResult> {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        let affected = getNextAffectedFile(state, cancellationToken, host);
        const programEmitKind = getBuilderFileEmit(state.compilerOptions);
        let emitKind: BuilderFileEmit = emitOnlyDtsFiles ?
            programEmitKind & BuilderFileEmit.AllDts : programEmitKind;
        if (!affected) {
            if (!state.compilerOptions.outFile) {
                const pendingAffectedFile = getNextAffectedFilePendingEmit(state, emitOnlyDtsFiles);
                if (pendingAffectedFile) {
                    // Emit pending affected file
                    ({ affectedFile: affected, emitKind } = pendingAffectedFile);
                }
                else {
                    const pendingForDiagnostics = getNextPendingEmitDiagnosticsFile(state);
                    if (pendingForDiagnostics) {
                        (state.seenEmittedFiles ??= new Map()).set(pendingForDiagnostics.affectedFile.resolvedPath, pendingForDiagnostics.seenKind | BuilderFileEmit.AllDts);
                        return {
                            result: { emitSkipped: true, diagnostics: pendingForDiagnostics.diagnostics },
                            affected: pendingForDiagnostics.affectedFile,
                        };
                    }
                }
            }
            else {
                // Emit program if it was pending emit
                if (state.programEmitPending) {
                    emitKind = state.programEmitPending;
                    if (emitOnlyDtsFiles) emitKind = emitKind & BuilderFileEmit.AllDts;
                    if (emitKind) affected = state.program!;
                }
                // Pending emit diagnostics
                if (!affected && state.emitDiagnosticsPerFile?.size) {
                    const seenKind = state.seenProgramEmit || BuilderFileEmit.None;
                    if (!(seenKind & BuilderFileEmit.AllDts)) {
                        state.seenProgramEmit = BuilderFileEmit.AllDts | seenKind;
                        const diagnostics: Diagnostic[] = [];
                        state.emitDiagnosticsPerFile.forEach(d => addRange(diagnostics, d));
                        return {
                            result: { emitSkipped: true, diagnostics },
                            affected: state.program,
                        };
                    }
                }
            }

            if (!affected) {
                // Emit buildinfo if pending
                if (!getBuildInfoEmitPending(state)) return undefined;
                const affected = state.program;
                const result = affected.emitBuildInfo(
                    writeFile || maybeBind(host, host.writeFile),
                    cancellationToken,
                );
                state.buildInfoEmitPending = false;
                return { result, affected };
            }
        }
        // Determine if we can do partial emit
        let emitOnly: EmitOnly | undefined;
        if (emitKind & BuilderFileEmit.AllJs) emitOnly = EmitOnly.Js;
        if (emitKind & BuilderFileEmit.AllDts) emitOnly = emitOnly === undefined ? EmitOnly.Dts : undefined;
        // Actual emit without buildInfo as we want to emit it later so the state is updated
        const result = state.program.emit(
            affected === state.program ? undefined : affected as SourceFile,
            getWriteFileCallback(writeFile, customTransformers),
            cancellationToken,
            emitOnly,
            customTransformers,
            /*forceDtsEmit*/ undefined,
            /*skipBuildInfo*/ true,
        );
        if (affected !== state.program) {
            // update affected files
            const affectedSourceFile = affected as SourceFile;
            state.seenAffectedFiles!.add(affectedSourceFile.resolvedPath);
            if (state.affectedFilesIndex !== undefined) state.affectedFilesIndex++;
            // Change in changeSet/affectedFilesPendingEmit, buildInfo needs to be emitted
            state.buildInfoEmitPending = true;
            // Update the pendingEmit for the file
            const existing = state.seenEmittedFiles?.get(affectedSourceFile.resolvedPath) || BuilderFileEmit.None;
            (state.seenEmittedFiles ??= new Map()).set(affectedSourceFile.resolvedPath, emitKind | existing);
            const existingPending = state.affectedFilesPendingEmit?.get(affectedSourceFile.resolvedPath) || programEmitKind;
            const pendingKind = getPendingEmitKind(existingPending, emitKind | existing);
            if (pendingKind) (state.affectedFilesPendingEmit ??= new Map()).set(affectedSourceFile.resolvedPath, pendingKind);
            else state.affectedFilesPendingEmit?.delete(affectedSourceFile.resolvedPath);
            if (result.diagnostics.length) (state.emitDiagnosticsPerFile ??= new Map()).set(affectedSourceFile.resolvedPath, result.diagnostics);
        }
        else {
            // No more changes remaining to emit
            state.changedFilesSet.clear();
            // Update program emit kind
            state.programEmitPending = state.changedFilesSet.size ?
                getPendingEmitKind(programEmitKind, emitKind) :
                state.programEmitPending ?
                getPendingEmitKind(state.programEmitPending, emitKind) :
                undefined;
            state.seenProgramEmit = emitKind | (state.seenProgramEmit || BuilderFileEmit.None);
            // Update the d.ts diagnostics since they always come with Location, skip diagnsotics without file,
            // they could be semantic diagnsotic with noEmitOnError or other kind of diagnostics
            let emitDiagnosticsPerFile: Map<Path, Diagnostic[]> | undefined;
            result.diagnostics.forEach(d => {
                if (!d.file) return; // Dont cache without fileName
                let diagnostics = emitDiagnosticsPerFile?.get(d.file.resolvedPath);
                if (!diagnostics) (emitDiagnosticsPerFile ??= new Map()).set(d.file.resolvedPath, diagnostics = []);
                diagnostics.push(d);
            });
            if (emitDiagnosticsPerFile) state.emitDiagnosticsPerFile = emitDiagnosticsPerFile;
            state.buildInfoEmitPending = true;
        }
        return { result, affected };
    }

    function getWriteFileCallback(
        writeFile: WriteFileCallback | undefined,
        customTransformers: CustomTransformers | undefined,
    ): WriteFileCallback | undefined {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        if (!getEmitDeclarations(state.compilerOptions)) return writeFile || maybeBind(host, host.writeFile);
        return (fileName, text, writeByteOrderMark, onError, sourceFiles, data) => {
            if (isDeclarationFileName(fileName)) {
                if (!state.compilerOptions.outFile) {
                    Debug.assert(sourceFiles?.length === 1);
                    let emitSignature;
                    if (!customTransformers) {
                        const file = sourceFiles[0];
                        const info = state.fileInfos.get(file.resolvedPath)!;
                        if (info.signature === file.version) {
                            const signature = computeSignatureWithDiagnostics(
                                state.program,
                                file,
                                text,
                                host,
                                data,
                            );
                            // With d.ts diagnostics they are also part of the signature so emitSignature will be different from it since its just hash of d.ts
                            if (!data?.diagnostics?.length) emitSignature = signature;
                            if (signature !== file.version) { // Update it
                                if (host.storeSignatureInfo) (state.signatureInfo ??= new Map()).set(file.resolvedPath, SignatureInfo.StoredSignatureAtEmit);
                                if (state.affectedFiles) {
                                    // Keep old signature so we know what to undo if cancellation happens
                                    const existing = state.oldSignatures?.get(file.resolvedPath);
                                    if (existing === undefined) (state.oldSignatures ??= new Map()).set(file.resolvedPath, info.signature || false);
                                    info.signature = signature;
                                }
                                else {
                                    // These are directly committed
                                    info.signature = signature;
                                }
                            }
                        }
                    }

                    // Store d.ts emit hash so later can be compared to check if d.ts has changed.
                    // Currently we do this only for composite projects since these are the only projects that can be referenced by other projects
                    // and would need their d.ts change time in --build mode
                    if (state.compilerOptions.composite) {
                        const filePath = sourceFiles[0].resolvedPath;
                        emitSignature = handleNewSignature(state.emitSignatures?.get(filePath), emitSignature);
                        if (!emitSignature) return data!.skippedDtsWrite = true;
                        (state.emitSignatures ??= new Map()).set(filePath, emitSignature);
                    }
                }
                else if (state.compilerOptions.composite) {
                    const newSignature = handleNewSignature(state.outSignature, /*newSignature*/ undefined);
                    if (!newSignature) return data!.skippedDtsWrite = true;
                    state.outSignature = newSignature;
                }
            }
            if (writeFile) writeFile(fileName, text, writeByteOrderMark, onError, sourceFiles, data);
            else if (host.writeFile) host.writeFile(fileName, text, writeByteOrderMark, onError, sourceFiles, data);
            else state.program.writeFile(fileName, text, writeByteOrderMark, onError, sourceFiles, data);

            /**
             * Compare to existing computed signature and store it or handle the changes in d.ts map option from before
             * returning undefined means that, we dont need to emit this d.ts file since its contents didnt change
             */
            function handleNewSignature(oldSignatureFormat: EmitSignature | undefined, newSignature: string | undefined) {
                const oldSignature = !oldSignatureFormat || isString(oldSignatureFormat) ? oldSignatureFormat : oldSignatureFormat[0];
                newSignature ??= computeSignature(text, host, data);
                // Dont write dts files if they didn't change
                if (newSignature === oldSignature) {
                    // If the signature was encoded as string the dts map options match so nothing to do
                    if (oldSignatureFormat === oldSignature) return undefined;
                    // Mark as differsOnlyInMap so that --build can reverse the timestamp so that
                    // the downstream projects dont detect this as change in d.ts file
                    else if (data) data.differsOnlyInMap = true;
                    else data = { differsOnlyInMap: true };
                }
                else {
                    state.hasChangedEmitSignature = true;
                    state.latestChangedDtsFile = fileName;
                }
                return newSignature;
            }
        };
    }

    /**
     * Emits the JavaScript and declaration files.
     * When targetSource file is specified, emits the files corresponding to that source file,
     * otherwise for the whole program.
     * In case of EmitAndSemanticDiagnosticsBuilderProgram, when targetSourceFile is specified,
     * it is assumed that that file is handled from affected file list. If targetSourceFile is not specified,
     * it will only emit all the affected files instead of whole program
     *
     * The first of writeFile if provided, writeFile of BuilderProgramHost if provided, writeFile of compiler host
     * in that order would be used to write the files
     */
    function emit(
        targetSourceFile: SourceFile | undefined,
        writeFile: WriteFileCallback | undefined,
        cancellationToken: CancellationToken | undefined,
        emitOnlyDtsFiles: boolean | undefined,
        customTransformers: CustomTransformers | undefined,
    ): EmitResult {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        if (kind === BuilderProgramKind.EmitAndSemanticDiagnosticsBuilderProgram) {
            assertSourceFileOkWithoutNextAffectedCall(state, targetSourceFile);
        }
        const result = handleNoEmitOptions(builderProgram, targetSourceFile, writeFile, cancellationToken);
        if (result) return result;

        // Emit only affected files if using builder for emit
        if (!targetSourceFile) {
            if (kind === BuilderProgramKind.EmitAndSemanticDiagnosticsBuilderProgram) {
                // Emit and report any errors we ran into.
                let sourceMaps: SourceMapEmitResult[] = [];
                let emitSkipped = false;
                let diagnostics: Diagnostic[] | undefined;
                let emittedFiles: string[] = [];

                let affectedEmitResult: AffectedFileResult<EmitResult>;
                while (
                    affectedEmitResult = emitNextAffectedFile(
                        writeFile,
                        cancellationToken,
                        emitOnlyDtsFiles,
                        customTransformers,
                    )
                ) {
                    emitSkipped = emitSkipped || affectedEmitResult.result.emitSkipped;
                    diagnostics = addRange(diagnostics, affectedEmitResult.result.diagnostics);
                    emittedFiles = addRange(emittedFiles, affectedEmitResult.result.emittedFiles);
                    sourceMaps = addRange(sourceMaps, affectedEmitResult.result.sourceMaps);
                }
                return {
                    emitSkipped,
                    diagnostics: diagnostics || emptyArray,
                    emittedFiles,
                    sourceMaps,
                };
            }
            // In non Emit builder, clear affected files pending emit
            else {
                clearAffectedFilesPendingEmit(state, emitOnlyDtsFiles);
            }
        }
        return state.program.emit(
            targetSourceFile,
            getWriteFileCallback(writeFile, customTransformers),
            cancellationToken,
            emitOnlyDtsFiles,
            customTransformers,
        );
    }

    /**
     * Return the semantic diagnostics for the next affected file or undefined if iteration is complete
     * If provided ignoreSourceFile would be called before getting the diagnostics and would ignore the sourceFile if the returned value was true
     */
    function getSemanticDiagnosticsOfNextAffectedFile(
        cancellationToken: CancellationToken | undefined,
        ignoreSourceFile?: (sourceFile: SourceFile) => boolean,
    ): AffectedFileResult<readonly Diagnostic[]> {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        while (true) {
            const affected = getNextAffectedFile(state, cancellationToken, host);
            let result;
            if (!affected) {
                if (state.checkPending && !state.compilerOptions.noCheck) {
                    state.checkPending = undefined;
                    state.buildInfoEmitPending = true;
                }
                return undefined; // Done
            }
            else if (affected !== state.program) {
                // Get diagnostics for the affected file if its not ignored
                const affectedSourceFile = affected as SourceFile;
                if (!ignoreSourceFile || !ignoreSourceFile(affectedSourceFile)) {
                    result = getSemanticDiagnosticsOfFile(state, affectedSourceFile, cancellationToken);
                }
                state.seenAffectedFiles!.add(affectedSourceFile.resolvedPath);
                state.affectedFilesIndex!++;
                // Change in changeSet, buildInfo needs to be emitted
                state.buildInfoEmitPending = true;
                if (!result) continue;
            }
            else {
                // When whole program is affected, get all semantic diagnostics (eg when --out or --outFile is specified)
                let diagnostics: Diagnostic[] | undefined;
                const semanticDiagnosticsPerFile: BuilderProgramState["semanticDiagnosticsPerFile"] = new Map();
                state.program.getSourceFiles().forEach(sourceFile =>
                    diagnostics = addRange(
                        diagnostics,
                        getSemanticDiagnosticsOfFile(
                            state,
                            sourceFile,
                            cancellationToken,
                            semanticDiagnosticsPerFile,
                        ),
                    )
                );
                state.semanticDiagnosticsPerFile = semanticDiagnosticsPerFile;
                result = diagnostics || emptyArray;
                state.changedFilesSet.clear();
                state.programEmitPending = getBuilderFileEmit(state.compilerOptions);
                if (!state.compilerOptions.noCheck) state.checkPending = undefined;
                state.buildInfoEmitPending = true;
            }
            return { result, affected };
        }
    }

    /**
     * Gets the semantic diagnostics from the program corresponding to this state of file (if provided) or whole program
     * The semantic diagnostics are cached and managed here
     * Note that it is assumed that when asked about semantic diagnostics through this API,
     * the file has been taken out of affected files so it is safe to use cache or get from program and cache the diagnostics
     * In case of SemanticDiagnosticsBuilderProgram if the source file is not provided,
     * it will iterate through all the affected files, to ensure that cache stays valid and yet provide a way to get all semantic diagnostics
     */
    function getSemanticDiagnostics(
        sourceFile: SourceFile | undefined,
        cancellationToken: CancellationToken | undefined,
    ): readonly Diagnostic[] {
        Debug.assert(isBuilderProgramStateWithDefinedProgram(state));
        assertSourceFileOkWithoutNextAffectedCall(state, sourceFile);
        if (sourceFile) {
            return getSemanticDiagnosticsOfFile(state, sourceFile, cancellationToken);
        }

        // When semantic builder asks for diagnostics of the whole program,
        // ensure that all the affected files are handled
        while (true) {
            const affectedResult = getSemanticDiagnosticsOfNextAffectedFile(cancellationToken);
            if (!affectedResult) break;
            // If we already calculated diagnostics for all files, return them
            if (affectedResult.affected === state.program) return affectedResult.result;
        }

        let diagnostics: Diagnostic[] | undefined;
        for (const sourceFile of state.program.getSourceFiles()) {
            diagnostics = addRange(diagnostics, getSemanticDiagnosticsOfFile(state, sourceFile, cancellationToken));
        }
        if (state.checkPending && !state.compilerOptions.noCheck) {
            state.checkPending = undefined;
            state.buildInfoEmitPending = true;
        }
        return diagnostics || emptyArray;
    }
}

function addToAffectedFilesPendingEmit(
    state: BuilderProgramState,
    affectedFilePendingEmit: Path,
    kind: BuilderFileEmit,
) {
    const existingKind = state.affectedFilesPendingEmit?.get(affectedFilePendingEmit) || BuilderFileEmit.None;
    (state.affectedFilesPendingEmit ??= new Map()).set(affectedFilePendingEmit, existingKind | kind);
    state.emitDiagnosticsPerFile?.delete(affectedFilePendingEmit);
}

/** @internal */
export function toBuilderStateFileInfoForMultiEmit(fileInfo: IncrementalMultiFileEmitBuildInfoFileInfo): BuilderState.FileInfo {
    return isString(fileInfo) ?
        { version: fileInfo, signature: fileInfo, affectsGlobalScope: undefined, impliedFormat: undefined } :
        isString(fileInfo.signature) ?
        fileInfo as BuilderState.FileInfo :
        { version: fileInfo.version, signature: fileInfo.signature === false ? undefined : fileInfo.version, affectsGlobalScope: fileInfo.affectsGlobalScope, impliedFormat: fileInfo.impliedFormat };
}

/** @internal */
export function toBuilderFileEmit(
    value: IncrementalBuildInfoFilePendingEmit,
    fullEmitForOptions: BuilderFileEmit,
): BuilderFileEmit {
    return isNumber(value) ? fullEmitForOptions : value[1] || BuilderFileEmit.Dts;
}

/** @internal */
export function toProgramEmitPending(
    value: IncrementalBuildInfoBundlePendingEmit,
    options: CompilerOptions | undefined,
): BuilderFileEmit | undefined {
    return !value ? getBuilderFileEmit(options || {}) : value;
}

/** @internal */
export function createBuilderProgramUsingIncrementalBuildInfo(
    buildInfo: IncrementalBuildInfo,
    buildInfoPath: string,
    host: ReadBuildProgramHost,
): EmitAndSemanticDiagnosticsBuilderProgram {
    const buildInfoDirectory = getDirectoryPath(getNormalizedAbsolutePath(buildInfoPath, host.getCurrentDirectory()));
    const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames());

    let state: ReusableBuilderProgramState;
    const filePaths = buildInfo.fileNames?.map(toPathInBuildInfoDirectory);
    let filePathsSetList: Set<Path>[] | undefined;
    const latestChangedDtsFile = buildInfo.latestChangedDtsFile ? toAbsolutePath(buildInfo.latestChangedDtsFile) : undefined;
    const fileInfos = new Map<Path, BuilderState.FileInfo>();
    if (isIncrementalBundleEmitBuildInfo(buildInfo)) {
        buildInfo.fileInfos.forEach((fileInfo, index) => {
            const path = toFilePath(index + 1 as IncrementalBuildInfoFileId);
            fileInfos.set(path, isString(fileInfo) ? { version: fileInfo, signature: undefined, affectsGlobalScope: undefined, impliedFormat: undefined } : fileInfo);
        });
        state = {
            fileInfos,
            compilerOptions: buildInfo.options ? convertToOptionsWithAbsolutePaths(buildInfo.options, toAbsolutePath) : {},
            semanticDiagnosticsPerFile: toPerFileSemanticDiagnostics(buildInfo.semanticDiagnosticsPerFile),
            emitDiagnosticsPerFile: toPerFileEmitDiagnostics(buildInfo.emitDiagnosticsPerFile),
            hasReusableDiagnostic: true,
            latestChangedDtsFile,
            outSignature: buildInfo.outSignature,
            programEmitPending: buildInfo.pendingEmit === undefined ? undefined : toProgramEmitPending(buildInfo.pendingEmit, buildInfo.options),
            hasErrors: buildInfo.errors,
            checkPending: buildInfo.checkPending,
        };
    }
    else {
        filePathsSetList = buildInfo.fileIdsList?.map(fileIds => new Set(fileIds.map(toFilePath)));
        const emitSignatures = buildInfo.options?.composite && !buildInfo.options.outFile ? new Map<Path, EmitSignature>() : undefined;
        buildInfo.fileInfos.forEach((fileInfo, index) => {
            const path = toFilePath(index + 1 as IncrementalBuildInfoFileId);
            const stateFileInfo = toBuilderStateFileInfoForMultiEmit(fileInfo);
            fileInfos.set(path, stateFileInfo);
            if (emitSignatures && stateFileInfo.signature) emitSignatures.set(path, stateFileInfo.signature);
        });
        buildInfo.emitSignatures?.forEach(value => {
            if (isNumber(value)) emitSignatures!.delete(toFilePath(value));
            else {
                const key = toFilePath(value[0]);
                emitSignatures!.set(
                    key,
                    !isString(value[1]) && !value[1].length ?
                        // File signature is emit signature but differs in map
                        [emitSignatures!.get(key)! as string] :
                        value[1],
                );
            }
        });
        const fullEmitForOptions = buildInfo.affectedFilesPendingEmit ? getBuilderFileEmit(buildInfo.options || {}) : undefined;
        state = {
            fileInfos,
            compilerOptions: buildInfo.options ? convertToOptionsWithAbsolutePaths(buildInfo.options, toAbsolutePath) : {},
            referencedMap: toManyToManyPathMap(buildInfo.referencedMap, buildInfo.options ?? {}),
            semanticDiagnosticsPerFile: toPerFileSemanticDiagnostics(buildInfo.semanticDiagnosticsPerFile),
            emitDiagnosticsPerFile: toPerFileEmitDiagnostics(buildInfo.emitDiagnosticsPerFile),
            hasReusableDiagnostic: true,
            affectedFilesPendingEmit: buildInfo.affectedFilesPendingEmit && arrayToMap(buildInfo.affectedFilesPendingEmit, value => toFilePath(isNumber(value) ? value : value[0]), value => toBuilderFileEmit(value, fullEmitForOptions!)),
            latestChangedDtsFile,
            emitSignatures: emitSignatures?.size ? emitSignatures : undefined,
            hasErrors: buildInfo.errors,
            checkPending: buildInfo.checkPending,
        };
    }

    return {
        state,
        getProgram: notImplemented,
        getProgramOrUndefined: returnUndefined,
        releaseProgram: noop,
        getCompilerOptions: () => state.compilerOptions,
        getSourceFile: notImplemented,
        getSourceFiles: notImplemented,
        getOptionsDiagnostics: notImplemented,
        getGlobalDiagnostics: notImplemented,
        getConfigFileParsingDiagnostics: notImplemented,
        getSyntacticDiagnostics: notImplemented,
        getDeclarationDiagnostics: notImplemented,
        getSemanticDiagnostics: notImplemented,
        emit: notImplemented,
        getAllDependencies: notImplemented,
        getCurrentDirectory: notImplemented,
        emitNextAffectedFile: notImplemented,
        getSemanticDiagnosticsOfNextAffectedFile: notImplemented,
        emitBuildInfo: notImplemented,
        close: noop,
        hasChangedEmitSignature: returnFalse,
    };

    function toPathInBuildInfoDirectory(path: string) {
        return toPath(path, buildInfoDirectory, getCanonicalFileName);
    }

    function toAbsolutePath(path: string) {
        return getNormalizedAbsolutePath(path, buildInfoDirectory);
    }

    function toFilePath(fileId: IncrementalBuildInfoFileId) {
        return filePaths[fileId - 1];
    }

    function toFilePathsSet(fileIdsListId: IncrementalBuildInfoFileIdListId) {
        return filePathsSetList![fileIdsListId - 1];
    }

    function toManyToManyPathMap(referenceMap: IncrementalBuildInfoReferencedMap | undefined, options: CompilerOptions): BuilderState.ManyToManyPathMap | undefined {
        const map = BuilderState.createReferencedMap(options);
        if (!map || !referenceMap) return map;
        referenceMap.forEach(([fileId, fileIdListId]) => map.set(toFilePath(fileId), toFilePathsSet(fileIdListId)));
        return map;
    }

    function toPerFileSemanticDiagnostics(
        diagnostics: readonly IncrementalBuildInfoDiagnostic[] | undefined,
    ) {
        const semanticDiagnostics = new Map<Path, readonly ReusableDiagnostic[]>(
            mapDefinedIterator(
                fileInfos.keys(),
                key => [key, emptyArray],
            ),
        );
        diagnostics?.forEach(value => {
            if (isNumber(value)) semanticDiagnostics.delete(toFilePath(value));
            else semanticDiagnostics.set(toFilePath(value[0]), value[1]);
        });
        return semanticDiagnostics;
    }

    function toPerFileEmitDiagnostics(diagnostics: readonly IncrementalBuildInfoEmitDiagnostic[] | undefined): Map<Path, readonly ReusableDiagnostic[]> | undefined {
        return diagnostics && arrayToMap(diagnostics, value => toFilePath(value[0]), value => value[1]);
    }
}

/** @internal */
export function getBuildInfoFileVersionMap(
    program: IncrementalBuildInfo,
    buildInfoPath: string,
    host: Pick<ReadBuildProgramHost, "useCaseSensitiveFileNames" | "getCurrentDirectory">,
) {
    const buildInfoDirectory = getDirectoryPath(getNormalizedAbsolutePath(buildInfoPath, host.getCurrentDirectory()));
    const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames());
    const fileInfos = new Map<Path, string>();
    let rootIndex = 0;
    // Root name to resolved
    const roots = new Map<Path, Path | undefined>();
    const resolvedRoots = new Map(program.resolvedRoot);
    program.fileInfos.forEach((fileInfo, index) => {
        const path = toPath(program.fileNames[index], buildInfoDirectory, getCanonicalFileName);
        const version = isString(fileInfo) ? fileInfo : fileInfo.version;
        fileInfos.set(path, version);
        if (rootIndex < program.root.length) {
            const current = program.root[rootIndex];
            const fileId = (index + 1) as IncrementalBuildInfoFileId;
            if (isArray(current)) {
                if (current[0] <= fileId && fileId <= current[1]) {
                    addRoot(fileId, path);
                    if (current[1] === fileId) rootIndex++;
                }
            }
            else if (current === fileId) {
                addRoot(fileId, path);
                rootIndex++;
            }
        }
    });
    return { fileInfos, roots };

    function addRoot(fileId: IncrementalBuildInfoFileId, path: Path) {
        const root = resolvedRoots.get(fileId);
        if (root) {
            roots.set(toPath(program.fileNames[root - 1], buildInfoDirectory, getCanonicalFileName), path);
        }
        else {
            roots.set(path, undefined);
        }
    }
}

/** @internal */
export function getNonIncrementalBuildInfoRoots(
    buildInfo: BuildInfo,
    buildInfoPath: string,
    host: Pick<ReadBuildProgramHost, "useCaseSensitiveFileNames" | "getCurrentDirectory">,
) {
    if (!isNonIncrementalBuildInfo(buildInfo)) return undefined;
    const buildInfoDirectory = getDirectoryPath(getNormalizedAbsolutePath(buildInfoPath, host.getCurrentDirectory()));
    const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames());
    return buildInfo.root.map(r => toPath(r, buildInfoDirectory, getCanonicalFileName));
}

/** @internal */
export function createRedirectedBuilderProgram(
    state: Pick<ReusableBuilderProgramState, "program" | "compilerOptions">,
    configFileParsingDiagnostics: readonly Diagnostic[],
): BuilderProgram {
    return {
        state: undefined!,
        getProgram,
        getProgramOrUndefined: () => state.program,
        releaseProgram: () => state.program = undefined,
        getCompilerOptions: () => state.compilerOptions,
        getSourceFile: fileName => getProgram().getSourceFile(fileName),
        getSourceFiles: () => getProgram().getSourceFiles(),
        getOptionsDiagnostics: cancellationToken => getProgram().getOptionsDiagnostics(cancellationToken),
        getGlobalDiagnostics: cancellationToken => getProgram().getGlobalDiagnostics(cancellationToken),
        getConfigFileParsingDiagnostics: () => configFileParsingDiagnostics,
        getSyntacticDiagnostics: (sourceFile, cancellationToken) => getProgram().getSyntacticDiagnostics(sourceFile, cancellationToken),
        getDeclarationDiagnostics: (sourceFile, cancellationToken) => getProgram().getDeclarationDiagnostics(sourceFile, cancellationToken),
        getSemanticDiagnostics: (sourceFile, cancellationToken) => getProgram().getSemanticDiagnostics(sourceFile, cancellationToken),
        emit: (sourceFile, writeFile, cancellationToken, emitOnlyDts, customTransformers) => getProgram().emit(sourceFile, writeFile, cancellationToken, emitOnlyDts, customTransformers),
        emitBuildInfo: (writeFile, cancellationToken) => getProgram().emitBuildInfo(writeFile, cancellationToken),
        getAllDependencies: notImplemented,
        getCurrentDirectory: () => getProgram().getCurrentDirectory(),
        close: noop,
    };

    function getProgram() {
        return Debug.checkDefined(state.program);
    }
}