use CompilerHost.realpath to resolve actual location for symlinks

src/compiler/diagnosticMessages.json

@@ -2752,6 +2752,10 @@
         "category": "Error",
         "code": 6129
     },
+    "Resolving real path for '{0}', result '{1}'": {
+        "category": "Message",
+        "code": 6130
+    },    
     "Variable '{0}' implicitly has an '{1}' type.": {
         "category": "Error",
         "code": 7005

src/compiler/program.ts

@@ -570,22 +570,29 @@ namespace ts {
         let resolvedFileName = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, nodeLoadModuleByRelativeName,
             failedLookupLocations, supportedExtensions, state);
 
-        if (resolvedFileName) {
-            return createResolvedModule(resolvedFileName, /*isExternalLibraryImport*/false, failedLookupLocations);
+        let isExternalLibraryImport = false;
+        if (!resolvedFileName)  {
+            if (moduleHasNonRelativeName(moduleName)) {
+                if (traceEnabled) {
+                    trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
+                }
+                resolvedFileName = loadModuleFromNodeModules(moduleName, containingDirectory, failedLookupLocations, state);
+                isExternalLibraryImport = resolvedFileName !== undefined;
+            }
+            else {
+                const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
+                resolvedFileName = nodeLoadModuleByRelativeName(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
+            }
         }
 
-        let isExternalLibraryImport = false;
-        if (moduleHasNonRelativeName(moduleName)) {
+        if (resolvedFileName && host.realpath) {
+            const originalFileName = resolvedFileName;
+            resolvedFileName = normalizePath(host.realpath(resolvedFileName));
             if (traceEnabled) {
-                trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
+                trace(host, Diagnostics.Resolving_real_path_for_0_result_1, originalFileName, resolvedFileName);
             }
-            resolvedFileName = loadModuleFromNodeModules(moduleName, containingDirectory, failedLookupLocations, state);
-            isExternalLibraryImport = resolvedFileName !== undefined;
-        }
-        else {
-            const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
-            resolvedFileName = nodeLoadModuleByRelativeName(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
         }
+
         return createResolvedModule(resolvedFileName, isExternalLibraryImport, failedLookupLocations);
     }
 
@@ -873,6 +880,7 @@ namespace ts {
         }
 
         const newLine = getNewLineCharacter(options);
+        const realpath = sys.realpath && ((path: string) => sys.realpath(path));
 
         return {
             getSourceFile,
@@ -886,7 +894,8 @@ namespace ts {
             fileExists: fileName => sys.fileExists(fileName),
             readFile: fileName => sys.readFile(fileName),
             trace: (s: string) => sys.write(s + newLine),
-            directoryExists: directoryName => sys.directoryExists(directoryName)
+            directoryExists: directoryName => sys.directoryExists(directoryName),
+            realpath
         };
     }
 

src/compiler/sys.ts

@@ -29,6 +29,7 @@ namespace ts {
         createHash?(data: string): string;
         getMemoryUsage?(): number;
         exit(exitCode?: number): void;
+        realpath?(path: string): string;
     }
 
     export interface FileWatcher {
@@ -73,6 +74,7 @@ namespace ts {
         readDirectory(path: string, extension?: string, exclude?: string[]): string[];
         watchFile?(path: string, callback: FileWatcherCallback): FileWatcher;
         watchDirectory?(path: string, callback: DirectoryWatcherCallback, recursive?: boolean): FileWatcher;
+        realpath(path: string): string;
     };
 
     export var sys: System = (function () {
@@ -527,12 +529,15 @@ namespace ts {
                 },
                 exit(exitCode?: number): void {
                     process.exit(exitCode);
+                },
+                realpath(path: string): string {
+                    return _fs.realpathSync(path);
                 }
             };
         }
 
         function getChakraSystem(): System {
-
+            const realpath = ChakraHost.realpath && ((path: string) => ChakraHost.realpath(path));
             return {
                 newLine: ChakraHost.newLine || "\r\n",
                 args: ChakraHost.args,
@@ -558,6 +563,7 @@ namespace ts {
                 getCurrentDirectory: () => ChakraHost.currentDirectory,
                 readDirectory: ChakraHost.readDirectory,
                 exit: ChakraHost.quit,
+                realpath
             };
         }
 

src/compiler/types.ts

@@ -2779,6 +2779,7 @@ namespace ts {
         readFile(fileName: string): string;
         trace?(s: string): void;
         directoryExists?(directoryName: string): boolean;
+        realpath?(path: string): string;
     }
 
     export interface ResolvedModule {

src/harness/compilerRunner.ts

@@ -89,16 +89,16 @@ class CompilerBaselineRunner extends RunnerBase {
                 otherFiles = [];
 
                 if (testCaseContent.settings["noImplicitReferences"] || /require\(/.test(lastUnit.content) || /reference\spath/.test(lastUnit.content)) {
-                    toBeCompiled.push({ unitName: this.makeUnitName(lastUnit.name, rootDir), content: lastUnit.content });
+                    toBeCompiled.push({ unitName: this.makeUnitName(lastUnit.name, rootDir), content: lastUnit.content, fileOptions: lastUnit.fileOptions });
                     units.forEach(unit => {
                         if (unit.name !== lastUnit.name) {
-                            otherFiles.push({ unitName: this.makeUnitName(unit.name, rootDir), content: unit.content });
+                            otherFiles.push({ unitName: this.makeUnitName(unit.name, rootDir), content: unit.content, fileOptions: unit.fileOptions });
                         }
                     });
                 }
                 else {
                     toBeCompiled = units.map(unit => {
-                        return { unitName: this.makeUnitName(unit.name, rootDir), content: unit.content };
+                        return { unitName: this.makeUnitName(unit.name, rootDir), content: unit.content, fileOptions: unit.fileOptions };
                     });
                 }
 

src/harness/harness.ts

@@ -855,21 +855,31 @@ namespace Harness {
             // Local get canonical file name function, that depends on passed in parameter for useCaseSensitiveFileNames
             const getCanonicalFileName = ts.createGetCanonicalFileName(useCaseSensitiveFileNames);
 
-            const fileMap: ts.FileMap<ts.SourceFile> = ts.createFileMap<ts.SourceFile>();
+            let realPathMap: ts.FileMap<string>;
+            const fileMap: ts.FileMap<() => ts.SourceFile> = ts.createFileMap<() => ts.SourceFile>();
             for (const file of inputFiles) {
                 if (file.content !== undefined) {
                     const fileName = ts.normalizePath(file.unitName);
-                    const sourceFile = createSourceFileAndAssertInvariants(fileName, file.content, scriptTarget);
                     const path = ts.toPath(file.unitName, currentDirectory, getCanonicalFileName);
-                    fileMap.set(path, sourceFile);
+                    if (file.fileOptions && file.fileOptions["symlink"]) {
+                        const link = file.fileOptions["symlink"];
+                        const linkPath = ts.toPath(link, currentDirectory, getCanonicalFileName);
+                        if (!realPathMap) {
+                            realPathMap = ts.createFileMap<string>();
+                        }
+                        realPathMap.set(linkPath, fileName);
+                        fileMap.set(path, (): ts.SourceFile => { throw new Error("Symlinks should always be resolved to a realpath first"); });
+                    }
+                    const sourceFile = createSourceFileAndAssertInvariants(fileName, file.content, scriptTarget);
+                    fileMap.set(path, () => sourceFile);
                 }
             }
 
             function getSourceFile(fileName: string, languageVersion: ts.ScriptTarget) {
                 fileName = ts.normalizePath(fileName);
                 const path = ts.toPath(fileName, currentDirectory, getCanonicalFileName);
                 if (fileMap.contains(path)) {
-                    return fileMap.get(path);
+                    return fileMap.get(path)();
                 }
                 else if (fileName === fourslashFileName) {
                     const tsFn = "tests/cases/fourslash/" + fourslashFileName;
@@ -898,11 +908,16 @@ namespace Harness {
                 useCaseSensitiveFileNames: () => useCaseSensitiveFileNames,
                 getNewLine: () => newLine,
                 fileExists: fileName => {
-                    return fileMap.contains(ts.toPath(fileName, currentDirectory, getCanonicalFileName));
+                    const path = ts.toPath(fileName, currentDirectory, getCanonicalFileName);
+                    return fileMap.contains(path) || (realPathMap && realPathMap.contains(path));
                 },
                 readFile: (fileName: string): string => {
-                    return fileMap.get(ts.toPath(fileName, currentDirectory, getCanonicalFileName)).getText();
-                }
+                    return fileMap.get(ts.toPath(fileName, currentDirectory, getCanonicalFileName))().getText();
+                },
+                realpath: realPathMap && ((f: string) => {
+                    const path = ts.toPath(f, currentDirectory, getCanonicalFileName);
+                    return realPathMap.contains(path) ? realPathMap.get(path) : path;
+                })
             };
         }
 
@@ -923,7 +938,8 @@ namespace Harness {
             { name: "libFiles", type: "string" },
             { name: "noErrorTruncation", type: "boolean" },
             { name: "suppressOutputPathCheck", type: "boolean" },
-            { name: "noImplicitReferences", type: "boolean" }
+            { name: "noImplicitReferences", type: "boolean" },
+            { name: "symlink", type: "string" }
         ];
 
         let optionsIndex: ts.Map<ts.CommandLineOption>;
@@ -978,6 +994,7 @@ namespace Harness {
         export interface TestFile {
             unitName: string;
             content: string;
+            fileOptions?: any;
         }
 
         export interface CompilationOutput {
@@ -1415,10 +1432,8 @@ namespace Harness {
                     // Comment line, check for global/file @options and record them
                     optionRegex.lastIndex = 0;
                     const metaDataName = testMetaData[1].toLowerCase();
-                    if (metaDataName === "filename") {
-                        currentFileOptions[testMetaData[1]] = testMetaData[2];
-                    }
-                    else {
+                    currentFileOptions[testMetaData[1]] = testMetaData[2];
+                    if (metaDataName !== "filename") {
                         continue;
                     }
 

src/services/shims.ts

@@ -431,11 +431,15 @@ namespace ts {
     export class CoreServicesShimHostAdapter implements ParseConfigHost, ModuleResolutionHost {
 
         public directoryExists: (directoryName: string) => boolean;
+        public realpath: (path: string) => string;
 
         constructor(private shimHost: CoreServicesShimHost) {
             if ("directoryExists" in this.shimHost) {
                 this.directoryExists = directoryName => this.shimHost.directoryExists(directoryName);
             }
+            if ("realpath" in this.shimHost) {
+                this.realpath = path => this.shimHost.realpath(path);
+            }
         }
 
         public readDirectory(rootDir: string, extension: string, exclude: string[], depth?: number): string[] {

tests/baselines/reference/moduleResolutionWithSymlinks.js

@@ -0,0 +1,37 @@
+//// [tests/cases/compiler/moduleResolutionWithSymlinks.ts] ////
+
+//// [index.ts]
+
+export class MyClass{}
+
+//// [index.ts]
+import {MyClass} from "library-a";
+export { MyClass as MyClass2 }
+
+//// [app.ts]
+import { MyClass } from "./library-a";
+import { MyClass2 } from "./library-b";
+
+let x: MyClass;
+let y: MyClass2;
+x = y;
+y = x;
+
+//// [index.js]
+"use strict";
+var MyClass = (function () {
+    function MyClass() {
+    }
+    return MyClass;
+}());
+exports.MyClass = MyClass;
+//// [index.js]
+"use strict";
+var library_a_1 = require("library-a");
+exports.MyClass2 = library_a_1.MyClass;
+//// [app.js]
+"use strict";
+var x;
+var y;
+x = y;
+y = x;

tests/baselines/reference/moduleResolutionWithSymlinks.symbols

@@ -0,0 +1,36 @@
+=== /src/app.ts ===
+import { MyClass } from "./library-a";
+>MyClass : Symbol(MyClass, Decl(app.ts, 0, 8))
+
+import { MyClass2 } from "./library-b";
+>MyClass2 : Symbol(MyClass2, Decl(app.ts, 1, 8))
+
+let x: MyClass;
+>x : Symbol(x, Decl(app.ts, 3, 3))
+>MyClass : Symbol(MyClass, Decl(app.ts, 0, 8))
+
+let y: MyClass2;
+>y : Symbol(y, Decl(app.ts, 4, 3))
+>MyClass2 : Symbol(MyClass2, Decl(app.ts, 1, 8))
+
+x = y;
+>x : Symbol(x, Decl(app.ts, 3, 3))
+>y : Symbol(y, Decl(app.ts, 4, 3))
+
+y = x;
+>y : Symbol(y, Decl(app.ts, 4, 3))
+>x : Symbol(x, Decl(app.ts, 3, 3))
+
+=== /src/library-a/index.ts ===
+
+export class MyClass{}
+>MyClass : Symbol(MyClass, Decl(index.ts, 0, 0))
+
+=== /src/library-b/index.ts ===
+import {MyClass} from "library-a";
+>MyClass : Symbol(MyClass, Decl(index.ts, 0, 8))
+
+export { MyClass as MyClass2 }
+>MyClass : Symbol(MyClass2, Decl(index.ts, 1, 8))
+>MyClass2 : Symbol(MyClass2, Decl(index.ts, 1, 8))
+

tests/baselines/reference/moduleResolutionWithSymlinks.trace.json

@@ -0,0 +1,32 @@
+[
+    "======== Resolving module './library-a' from '/src/app.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/src/library-a'.",
+    "File '/src/library-a.ts' does not exist.",
+    "File '/src/library-a.tsx' does not exist.",
+    "File '/src/library-a.d.ts' does not exist.",
+    "File '/src/library-a/package.json' does not exist.",
+    "File '/src/library-a/index.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/src/library-a/index.ts', result '/src/library-a/index.ts'",
+    "======== Module name './library-a' was successfully resolved to '/src/library-a/index.ts'. ========",
+    "======== Resolving module './library-b' from '/src/app.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module as file / folder, candidate module location '/src/library-b'.",
+    "File '/src/library-b.ts' does not exist.",
+    "File '/src/library-b.tsx' does not exist.",
+    "File '/src/library-b.d.ts' does not exist.",
+    "File '/src/library-b/package.json' does not exist.",
+    "File '/src/library-b/index.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/src/library-b/index.ts', result '/src/library-b/index.ts'",
+    "======== Module name './library-b' was successfully resolved to '/src/library-b/index.ts'. ========",
+    "======== Resolving module 'library-a' from '/src/library-b/index.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'library-a' from 'node_modules' folder.",
+    "File '/src/library-b/node_modules/library-a.ts' does not exist.",
+    "File '/src/library-b/node_modules/library-a.tsx' does not exist.",
+    "File '/src/library-b/node_modules/library-a.d.ts' does not exist.",
+    "File '/src/library-b/node_modules/library-a/package.json' does not exist.",
+    "File '/src/library-b/node_modules/library-a/index.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/src/library-b/node_modules/library-a/index.ts', result '/src/library-a/index.ts'",
+    "======== Module name 'library-a' was successfully resolved to '/src/library-a/index.ts'. ========"
+]

tests/baselines/reference/moduleResolutionWithSymlinks.types

@@ -0,0 +1,38 @@
+=== /src/app.ts ===
+import { MyClass } from "./library-a";
+>MyClass : typeof MyClass
+
+import { MyClass2 } from "./library-b";
+>MyClass2 : typeof MyClass
+
+let x: MyClass;
+>x : MyClass
+>MyClass : MyClass
+
+let y: MyClass2;
+>y : MyClass
+>MyClass2 : MyClass
+
+x = y;
+>x = y : MyClass
+>x : MyClass
+>y : MyClass
+
+y = x;
+>y = x : MyClass
+>y : MyClass
+>x : MyClass
+
+=== /src/library-a/index.ts ===
+
+export class MyClass{}
+>MyClass : MyClass
+
+=== /src/library-b/index.ts ===
+import {MyClass} from "library-a";
+>MyClass : typeof MyClass
+
+export { MyClass as MyClass2 }
+>MyClass : typeof MyClass
+>MyClass2 : typeof MyClass
+