Port import type declaration updates

src/compiler/checker.ts

@@ -4092,7 +4092,15 @@ namespace ts {
                         // ambient module, just use declaration/symbol name (fallthrough)
                     }
                     else {
-                        return `"${getResolvedExternalModuleName(context.tracker.moduleResolverHost, file, getSourceFileOfNode(getOriginalNode(context.enclosingDeclaration)))}"`;
+                        const contextFile = getSourceFileOfNode(getOriginalNode(context!.enclosingDeclaration))!;
+                        return `"${file.moduleName || moduleSpecifiers.getModuleSpecifiers(
+                            symbol,
+                            compilerOptions,
+                            contextFile,
+                            context!.tracker.moduleResolverHost!,
+                            context!.tracker.moduleResolverHost!.getSourceFiles!(),
+                            { importModuleSpecifierPreference: "non-relative" }
+                        )[0]}"`;
                     }
                 }
                 const declaration = symbol.declarations[0];

src/compiler/moduleNameResolver.ts

@@ -132,10 +132,6 @@ namespace ts {
         }
     }
 
-    export interface GetEffectiveTypeRootsHost {
-        directoryExists?(directoryName: string): boolean;
-        getCurrentDirectory?(): string;
-    }
     export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffectiveTypeRootsHost): string[] | undefined {
         if (options.typeRoots) {
             return options.typeRoots;

src/services/codefixes/moduleSpecifiers.ts → src/compiler/moduleSpecifiers.ts

@@ -1,28 +1,34 @@
 // Used by importFixes to synthesize import module specifiers.
 /* @internal */
 namespace ts.moduleSpecifiers {
+    export interface ModuleSpecifierPreferences {
+        importModuleSpecifierPreference?: "relative" | "non-relative";
+    }
+
     // Note: fromSourceFile is just for usesJsExtensionOnImports
-    export function getModuleSpecifier(program: Program, fromSourceFile: SourceFile, fromSourceFileName: string, toFileName: string, host: LanguageServiceHost, preferences: UserPreferences) {
-        const info = getInfo(program.getCompilerOptions(), fromSourceFile, fromSourceFileName, host);
-        const compilerOptions = program.getCompilerOptions();
+    export function getModuleSpecifier(compilerOptions: CompilerOptions, fromSourceFile: SourceFile, fromSourceFileName: string, toFileName: string, host: ModuleSpecifierResolutionHost, preferences: ModuleSpecifierPreferences = {}) {
+        const info = getInfo(compilerOptions, fromSourceFile, fromSourceFileName, host);
         return getGlobalModuleSpecifier(toFileName, info, host, compilerOptions) ||
             first(getLocalModuleSpecifiers(toFileName, info, compilerOptions, preferences));
     }
 
     // For each symlink/original for a module, returns a list of ways to import that file.
     export function getModuleSpecifiers(
         moduleSymbol: Symbol,
-        program: Program,
+        compilerOptions: CompilerOptions,
         importingSourceFile: SourceFile,
-        host: LanguageServiceHost,
-        preferences: UserPreferences,
+        host: ModuleSpecifierResolutionHost,
+        files: ReadonlyArray<SourceFile>,
+        preferences: ModuleSpecifierPreferences,
     ): ReadonlyArray<ReadonlyArray<string>> {
         const ambient = tryGetModuleNameFromAmbientModule(moduleSymbol);
         if (ambient) return [[ambient]];
 
-        const compilerOptions = program.getCompilerOptions();
-        const info = getInfo(compilerOptions, importingSourceFile, importingSourceFile.fileName, host);
-        const modulePaths = getAllModulePaths(program, moduleSymbol.valueDeclaration.getSourceFile());
+        const info = getInfo(compilerOptions, importingSourceFile, importingSourceFile.path, host);
+        if (!files) {
+            return Debug.fail("Files list must be present to resolve symlinks in specifier resolution");
+        }
+        const modulePaths = getAllModulePaths(files, getSourceFileOfNode(moduleSymbol.valueDeclaration), info.getCanonicalFileName, host);
 
         const global = mapDefined(modulePaths, moduleFileName => getGlobalModuleSpecifier(moduleFileName, info, host, compilerOptions));
         return global.length ? global.map(g => [g]) : modulePaths.map(moduleFileName =>
@@ -36,18 +42,18 @@ namespace ts.moduleSpecifiers {
         readonly sourceDirectory: string;
     }
     // importingSourceFileName is separate because getEditsForFileRename may need to specify an updated path
-    function getInfo(compilerOptions: CompilerOptions, importingSourceFile: SourceFile, importingSourceFileName: string, host: LanguageServiceHost): Info {
+    function getInfo(compilerOptions: CompilerOptions, importingSourceFile: SourceFile, importingSourceFileName: string, host: ModuleSpecifierResolutionHost): Info {
         const moduleResolutionKind = getEmitModuleResolutionKind(compilerOptions);
         const addJsExtension = usesJsExtensionOnImports(importingSourceFile);
-        const getCanonicalFileName = hostGetCanonicalFileName(host);
+        const getCanonicalFileName = createGetCanonicalFileName(host.useCaseSensitiveFileNames ? host.useCaseSensitiveFileNames() : true);
         const sourceDirectory = getDirectoryPath(importingSourceFileName);
         return { moduleResolutionKind, addJsExtension, getCanonicalFileName, sourceDirectory };
     }
 
     function getGlobalModuleSpecifier(
         moduleFileName: string,
         { addJsExtension, getCanonicalFileName, sourceDirectory }: Info,
-        host: LanguageServiceHost,
+        host: ModuleSpecifierResolutionHost,
         compilerOptions: CompilerOptions,
     ) {
         return tryGetModuleNameFromTypeRoots(compilerOptions, host, getCanonicalFileName, moduleFileName, addJsExtension)
@@ -59,7 +65,7 @@ namespace ts.moduleSpecifiers {
         moduleFileName: string,
         { moduleResolutionKind, addJsExtension, getCanonicalFileName, sourceDirectory }: Info,
         compilerOptions: CompilerOptions,
-        preferences: UserPreferences,
+        preferences: ModuleSpecifierPreferences,
     ) {
         const { baseUrl, paths } = compilerOptions;
 
@@ -127,15 +133,57 @@ namespace ts.moduleSpecifiers {
         return firstDefined(imports, ({ text }) => pathIsRelative(text) ? fileExtensionIs(text, Extension.Js) : undefined) || false;
     }
 
+    function discoverProbableSymlinks(files: ReadonlyArray<SourceFile>) {
+        const symlinks = mapDefined(files, sf =>
+            sf.resolvedModules && firstDefinedIterator(sf.resolvedModules.values(), res =>
+                res && res.originalPath && res.resolvedFileName !== res.originalPath ? [res.resolvedFileName, res.originalPath] : undefined));
+        const result = createMap<string>();
+        if (symlinks) {
+            for (const [resolvedPath, originalPath] of symlinks) {
+                const resolvedParts = getPathComponents(resolvedPath);
+                const originalParts = getPathComponents(originalPath);
+                while (resolvedParts[resolvedParts.length - 1] === originalParts[originalParts.length - 1]) {
+                    resolvedParts.pop();
+                    originalParts.pop();
+                }
+                result.set(getPathFromPathComponents(originalParts), getPathFromPathComponents(resolvedParts));
+            }
+        }
+        return result;
+    }
+
+    function getAllModulePathsUsingIndirectSymlinks(files: ReadonlyArray<SourceFile>, target: string, getCanonicalFileName: (file: string) => string, host: ModuleSpecifierResolutionHost) {
+        const links = discoverProbableSymlinks(files);
+        const paths = arrayFrom(links.keys());
+        let options: string[] | undefined;
+        for (const path of paths) {
+            const resolved = links.get(path)!;
+            if (startsWith(target, resolved + "/")) {
+                const relative = getRelativePathFromDirectory(resolved, target, getCanonicalFileName);
+                const option = resolvePath(path, relative);
+                if (!host.fileExists || host.fileExists(option)) {
+                    if (!options) options = [];
+                    options.push(option);
+                }
+            }
+        }
+        const resolvedtarget = host.getCurrentDirectory ? resolvePath(host.getCurrentDirectory(), target) : target;
+        if (options) {
+            options.push(resolvedtarget); // Since these are speculative, we also include the original resolved name as a possibility
+            return options;
+        }
+        return [resolvedtarget];
+    }
+
     /**
      * Looks for a existing imports that use symlinks to this module.
      * Only if no symlink is available, the real path will be used.
      */
-    function getAllModulePaths(program: Program, { fileName }: SourceFile): ReadonlyArray<string> {
-        const symlinks = mapDefined(program.getSourceFiles(), sf =>
+    function getAllModulePaths(files: ReadonlyArray<SourceFile>, { fileName }: SourceFile, getCanonicalFileName: (file: string) => string, host: ModuleSpecifierResolutionHost): ReadonlyArray<string> {
+        const symlinks = mapDefined(files, sf =>
             sf.resolvedModules && firstDefinedIterator(sf.resolvedModules.values(), res =>
                 res && res.resolvedFileName === fileName ? res.originalPath : undefined));
-        return symlinks.length === 0 ? [fileName] : symlinks;
+        return symlinks.length === 0 ? getAllModulePathsUsingIndirectSymlinks(files, fileName, getCanonicalFileName, host) : symlinks;
     }
 
     function getRelativePathNParents(relativePath: string): number {
@@ -210,7 +258,7 @@ namespace ts.moduleSpecifiers {
     function tryGetModuleNameAsNodeModule(
         options: CompilerOptions,
         moduleFileName: string,
-        host: LanguageServiceHost,
+        host: ModuleSpecifierResolutionHost,
         getCanonicalFileName: (file: string) => string,
         sourceDirectory: string,
     ): string | undefined {
@@ -255,7 +303,8 @@ namespace ts.moduleSpecifiers {
             const fullModulePathWithoutExtension = removeFileExtension(path);
 
             // If the file is /index, it can be imported by its directory name
-            if (getCanonicalFileName(fullModulePathWithoutExtension.substring(parts.fileNameIndex)) === "/index") {
+            // IFF there is not _also_ a file by the same name
+            if (getCanonicalFileName(fullModulePathWithoutExtension.substring(parts.fileNameIndex)) === "/index" && !tryGetAnyFileFromPath(host, fullModulePathWithoutExtension.substring(0, parts.fileNameIndex))) {
                 return fullModulePathWithoutExtension.substring(0, parts.fileNameIndex);
             }
 
@@ -274,6 +323,17 @@ namespace ts.moduleSpecifiers {
         }
     }
 
+    function tryGetAnyFileFromPath(host: ModuleSpecifierResolutionHost, path: string) {
+        // We check all js, `node` and `json` extensions in addition to TS, since node module resolution would also choose those over the directory
+        const extensions = getSupportedExtensions({ allowJs: true }, [{ extension: "node", isMixedContent: false }, { extension: "json", isMixedContent: false, scriptKind: ScriptKind.JSON }]);
+        for (const e of extensions) {
+            const fullPath = path + e;
+            if (host.fileExists!(fullPath)) { // TODO: GH#18217
+                return fullPath;
+            }
+        }
+    }
+
     function getNodeModulePathParts(fullPath: string) {
         // If fullPath can't be valid module file within node_modules, returns undefined.
         // Example of expected pattern: /base/path/node_modules/[@scope/otherpackage/@otherscope/node_modules/]package/[subdirectory/]file.js

src/compiler/program.ts

@@ -1168,6 +1168,9 @@ namespace ts {
                 writeFile: writeFileCallback || (
                     (fileName, data, writeByteOrderMark, onError, sourceFiles) => host.writeFile(fileName, data, writeByteOrderMark, onError, sourceFiles)),
                 isEmitBlocked,
+                readFile: f => host.readFile(f),
+                fileExists: f => host.fileExists(f),
+                ...(host.directoryExists ? { directoryExists: f => host.directoryExists!(f) } : {}),
             };
         }
 

src/compiler/tsconfig.json

@@ -44,6 +44,7 @@
         "builderState.ts",
         "builder.ts",
         "resolutionCache.ts",
+        "moduleSpecifiers.ts",
         "watch.ts",
         "commandLineParser.ts",
         "tsc.ts"

src/compiler/types.ts

@@ -5011,8 +5011,9 @@ namespace ts {
     }
 
     /* @internal */
-    export interface EmitHost extends ScriptReferenceHost {
+    export interface EmitHost extends ScriptReferenceHost, ModuleSpecifierResolutionHost {
         getSourceFiles(): ReadonlyArray<SourceFile>;
+        getCurrentDirectory(): string;
 
         /* @internal */
         isSourceFileFromExternalLibrary(file: SourceFile): boolean;
@@ -5274,11 +5275,16 @@ namespace ts {
         isAtStartOfLine(): boolean;
     }
 
-    /* @internal */
-    export interface ModuleNameResolverHost {
-        getCanonicalFileName(f: string): string;
-        getCommonSourceDirectory(): string;
-        getCurrentDirectory(): string;
+    export interface GetEffectiveTypeRootsHost {
+        directoryExists?(directoryName: string): boolean;
+        getCurrentDirectory?(): string;
+    }
+    /** @internal */
+    export interface ModuleSpecifierResolutionHost extends GetEffectiveTypeRootsHost {
+        useCaseSensitiveFileNames?(): boolean;
+        fileExists?(path: string): boolean;
+        readFile?(path: string): string | undefined;
+        getSourceFiles?(): ReadonlyArray<SourceFile>; // Used for cached resolutions to find symlinks without traversing the fs (again)
     }
 
     /** @deprecated See comment on SymbolWriter */
@@ -5292,7 +5298,7 @@ namespace ts {
         reportPrivateInBaseOfClassExpression?(propertyName: string): void;
         reportInaccessibleUniqueSymbolError?(): void;
         /* @internal */
-        moduleResolverHost?: ModuleNameResolverHost;
+        moduleResolverHost?: ModuleSpecifierResolutionHost;
         /* @internal */
         trackReferencedAmbientModule?(decl: ModuleDeclaration): void;
     }

src/compiler/utilities.ts

@@ -2893,11 +2893,11 @@ namespace ts {
         };
     }
 
-    export function getResolvedExternalModuleName(host: ModuleNameResolverHost, file: SourceFile, referenceFile?: SourceFile): string {
+    export function getResolvedExternalModuleName(host: EmitHost, file: SourceFile, referenceFile?: SourceFile): string {
         return file.moduleName || getExternalModuleNameFromPath(host, file.fileName, referenceFile && referenceFile.fileName);
     }
 
-    export function getExternalModuleNameFromDeclaration(host: ModuleNameResolverHost, resolver: EmitResolver, declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration | ModuleDeclaration | ImportTypeNode): string {
+    export function getExternalModuleNameFromDeclaration(host: EmitHost, resolver: EmitResolver, declaration: ImportEqualsDeclaration | ImportDeclaration | ExportDeclaration | ModuleDeclaration | ImportTypeNode): string | undefined {
         const file = resolver.getExternalModuleFileFromDeclaration(declaration);
         if (!file || file.isDeclarationFile) {
             return undefined;
@@ -2908,7 +2908,7 @@ namespace ts {
     /**
      * Resolves a local path to a path which is absolute to the base of the emit
      */
-    export function getExternalModuleNameFromPath(host: ModuleNameResolverHost, fileName: string, referencePath?: string): string {
+    export function getExternalModuleNameFromPath(host: EmitHost, fileName: string, referencePath?: string): string {
         const getCanonicalFileName = (f: string) => host.getCanonicalFileName(f);
         const dir = toPath(referencePath ? getDirectoryPath(referencePath) : host.getCommonSourceDirectory(), host.getCurrentDirectory(), getCanonicalFileName);
         const filePath = getNormalizedAbsolutePath(fileName, host.getCurrentDirectory());

src/harness/compilerRunner.ts

@@ -187,7 +187,9 @@ class CompilerTest {
             this.otherFiles,
             this.harnessSettings,
             /*options*/ tsConfigOptions,
-            /*currentDirectory*/ this.harnessSettings.currentDirectory);
+            /*currentDirectory*/ this.harnessSettings.currentDirectory,
+            testCaseContent.symlinks
+        );
 
         this.options = this.result.options;
     }