Handle auto import scenarios when using project references

src/compiler/checker.ts

@@ -4070,6 +4070,9 @@ namespace ts {
                         getProbableSymlinks: maybeBind(host, host.getProbableSymlinks),
                         useCaseSensitiveFileNames: maybeBind(host, host.useCaseSensitiveFileNames),
                         redirectTargetsMap: host.redirectTargetsMap,
+                        getProjectReferenceRedirect: fileName => host.getProjectReferenceRedirect(fileName),
+                        isSourceOfProjectReferenceRedirect: fileName => host.isSourceOfProjectReferenceRedirect(fileName),
+                        fileExists: fileName => host.fileExists(fileName),
                     } : undefined },
                     encounteredError: false,
                     visitedTypes: undefined,

src/compiler/emitter.ts

@@ -759,6 +759,7 @@ namespace ts {
             getLibFileFromReference: notImplemented,
             isSourceFileFromExternalLibrary: returnFalse,
             getResolvedProjectReferenceToRedirect: returnUndefined,
+            getProjectReferenceRedirect: returnUndefined,
             isSourceOfProjectReferenceRedirect: returnFalse,
             writeFile: (name, text, writeByteOrderMark) => {
                 switch (name) {

src/compiler/moduleSpecifiers.ts

@@ -177,8 +177,9 @@ namespace ts.moduleSpecifiers {
     ): T | undefined {
         const getCanonicalFileName = hostGetCanonicalFileName(host);
         const cwd = host.getCurrentDirectory();
+        const referenceRedirect = host.isSourceOfProjectReferenceRedirect(importedFileName) ? host.getProjectReferenceRedirect(importedFileName) : undefined;
         const redirects = host.redirectTargetsMap.get(toPath(importedFileName, cwd, getCanonicalFileName)) || emptyArray;
-        const importedFileNames = [importedFileName, ...redirects];
+        const importedFileNames = [...(referenceRedirect ? [referenceRedirect] : emptyArray), importedFileName, ...redirects];
         const targets = importedFileNames.map(f => getNormalizedAbsolutePath(f, cwd));
         if (!preferSymlinks) {
             const result = forEach(targets, cb);

src/compiler/program.ts

@@ -809,7 +809,7 @@ namespace ts {
 
         const useSourceOfProjectReferenceRedirect = !!host.useSourceOfProjectReferenceRedirect?.() &&
             !options.disableSourceOfProjectReferenceRedirect;
-        const onProgramCreateComplete = updateHostForUseSourceOfProjectReferenceRedirect({
+        const { onProgramCreateComplete, fileExists } = updateHostForUseSourceOfProjectReferenceRedirect({
             compilerHost: host,
             useSourceOfProjectReferenceRedirect,
             toPath,
@@ -970,6 +970,7 @@ namespace ts {
             forEachResolvedProjectReference,
             isSourceOfProjectReferenceRedirect,
             emitBuildInfo,
+            fileExists,
             getProbableSymlinks,
             useCaseSensitiveFileNames: () => host.useCaseSensitiveFileNames(),
         };
@@ -1479,6 +1480,7 @@ namespace ts {
                 getLibFileFromReference: program.getLibFileFromReference,
                 isSourceFileFromExternalLibrary,
                 getResolvedProjectReferenceToRedirect,
+                getProjectReferenceRedirect,
                 isSourceOfProjectReferenceRedirect,
                 getProbableSymlinks,
                 writeFile: writeFileCallback || (
@@ -3482,20 +3484,9 @@ namespace ts {
         const originalGetDirectories = host.compilerHost.getDirectories;
         const originalRealpath = host.compilerHost.realpath;
 
+        if (!host.useSourceOfProjectReferenceRedirect) return { onProgramCreateComplete: noop, fileExists };
 
-        if (!host.useSourceOfProjectReferenceRedirect) return noop;
-
-        // This implementation of fileExists checks if the file being requested is
-        // .d.ts file for the referenced Project.
-        // If it is it returns true irrespective of whether that file exists on host
-        host.compilerHost.fileExists = (file) => {
-            if (originalFileExists.call(host.compilerHost, file)) return true;
-            if (!host.getResolvedProjectReferences()) return false;
-            if (!isDeclarationFileName(file)) return false;
-
-            // Project references go to source file instead of .d.ts file
-            return fileOrDirectoryExistsUsingSource(file, /*isFile*/ true);
-        };
+        host.compilerHost.fileExists = fileExists;
 
         if (originalDirectoryExists) {
             // This implementation of directoryExists checks if the directory being requested is
@@ -3547,8 +3538,7 @@ namespace ts {
                 originalRealpath.call(host.compilerHost, s);
         }
 
-        return onProgramCreateComplete;
-
+        return { onProgramCreateComplete, fileExists };
 
         function onProgramCreateComplete() {
             host.compilerHost.fileExists = originalFileExists;
@@ -3557,6 +3547,18 @@ namespace ts {
             // DO not revert realpath as it could be used later
         }
 
+        // This implementation of fileExists checks if the file being requested is
+        // .d.ts file for the referenced Project.
+        // If it is it returns true irrespective of whether that file exists on host
+        function fileExists(file: string) {
+            if (originalFileExists.call(host.compilerHost, file)) return true;
+            if (!host.getResolvedProjectReferences()) return false;
+            if (!isDeclarationFileName(file)) return false;
+
+            // Project references go to source file instead of .d.ts file
+            return fileOrDirectoryExistsUsingSource(file, /*isFile*/ true);
+        }
+
         function fileExistsIfProjectReferenceDts(file: string) {
             const source = host.getSourceOfProjectReferenceRedirect(file);
             return source !== undefined ?

src/compiler/types.ts

@@ -3287,6 +3287,10 @@ namespace ts {
         /*@internal*/ getProgramBuildInfo?(): ProgramBuildInfo | undefined;
         /*@internal*/ emitBuildInfo(writeFile?: WriteFileCallback, cancellationToken?: CancellationToken): EmitResult;
         /*@internal*/ getProbableSymlinks(): ReadonlyMap<string>;
+        /**
+         * This implementation handles file exists to be true if file is source of project reference redirect when program is created using useSourceOfProjectReferenceRedirect
+         */
+        /*@internal*/ fileExists(fileName: string): boolean;
     }
 
     /*@internal*/
@@ -6428,16 +6432,16 @@ namespace ts {
     /*@internal*/
     export interface ModuleSpecifierResolutionHost {
         useCaseSensitiveFileNames?(): boolean;
-        fileExists?(path: string): boolean;
+        fileExists(path: string): boolean;
         getCurrentDirectory(): string;
         readFile?(path: string): string | undefined;
-        /* @internal */
         getProbableSymlinks?(files: readonly SourceFile[]): ReadonlyMap<string>;
-        /* @internal */
         getGlobalTypingsCacheLocation?(): string | undefined;
 
         getSourceFiles(): readonly SourceFile[];
         readonly redirectTargetsMap: RedirectTargetsMap;
+        getProjectReferenceRedirect(fileName: string): string | undefined;
+        isSourceOfProjectReferenceRedirect(fileName: string): boolean;
     }
 
     // Note: this used to be deprecated in our public API, but is still used internally

src/services/utilities.ts

@@ -1705,14 +1705,16 @@ namespace ts {
         // Mix in `getProbableSymlinks` from Program when host doesn't have it
         // in order for non-Project hosts to have a symlinks cache.
         return {
-            fileExists: maybeBind(host, host.fileExists),
+            fileExists: fileName => program.fileExists(fileName),
             getCurrentDirectory: () => host.getCurrentDirectory(),
             readFile: maybeBind(host, host.readFile),
             useCaseSensitiveFileNames: maybeBind(host, host.useCaseSensitiveFileNames),
             getProbableSymlinks: maybeBind(host, host.getProbableSymlinks) || (() => program.getProbableSymlinks()),
             getGlobalTypingsCacheLocation: maybeBind(host, host.getGlobalTypingsCacheLocation),
             getSourceFiles: () => program.getSourceFiles(),
-            redirectTargetsMap: program.redirectTargetsMap
+            redirectTargetsMap: program.redirectTargetsMap,
+            getProjectReferenceRedirect: fileName => program.getProjectReferenceRedirect(fileName),
+            isSourceOfProjectReferenceRedirect: fileName => program.isSourceOfProjectReferenceRedirect(fileName),
         };
     }
 

src/testRunner/unittests/tsserver/projectReferenceErrors.ts

@@ -353,7 +353,7 @@ fnErr();
                             { line: 4, offset: 5 },
                             { line: 4, offset: 10 },
                             Diagnostics.Module_0_has_no_exported_member_1,
-                            [`"../dependency/fns"`, "fnErr"],
+                            [`"../decls/fns"`, "fnErr"],
                             "error",
                         )
                     ],

src/testRunner/unittests/tsserver/projectReferences.ts

@@ -2173,5 +2173,114 @@ foo;`
                 });
             });
         });
+
+        describe("auto import with referenced project", () => {
+            function verifyAutoImport(built: boolean, disableSourceOfProjectReferenceRedirect?: boolean) {
+                const solnConfig: File = {
+                    path: `${tscWatch.projectRoot}/tsconfig.json`,
+                    content: JSON.stringify({
+                        files: [],
+                        references: [
+                            { path: "shared/src/library" },
+                            { path: "app/src/program" }
+                        ]
+                    })
+                };
+                const sharedConfig: File = {
+                    path: `${tscWatch.projectRoot}/shared/src/library/tsconfig.json`,
+                    content: JSON.stringify({
+                        compilerOptions: {
+                            composite: true,
+                            outDir: "../../bld/library"
+                        }
+                    })
+                };
+                const sharedIndex: File = {
+                    path: `${tscWatch.projectRoot}/shared/src/library/index.ts`,
+                    content: `export function foo() {}`
+                };
+                const sharedPackage: File = {
+                    path: `${tscWatch.projectRoot}/shared/package.json`,
+                    content: JSON.stringify({
+                        name: "shared",
+                        version: "1.0.0",
+                        main: "bld/library/index.js",
+                        types: "bld/library/index.d.ts"
+                    })
+                };
+                const appConfig: File = {
+                    path: `${tscWatch.projectRoot}/app/src/program/tsconfig.json`,
+                    content: JSON.stringify({
+                        compilerOptions: {
+                            composite: true,
+                            outDir: "../../bld/program",
+                            disableSourceOfProjectReferenceRedirect
+                        },
+                        references: [
+                            { path: "../../../shared/src/library" }
+                        ]
+                    })
+                };
+                const appBar: File = {
+                    path: `${tscWatch.projectRoot}/app/src/program/bar.ts`,
+                    content: `import {foo} from "shared";`
+                };
+                const appIndex: File = {
+                    path: `${tscWatch.projectRoot}/app/src/program/index.ts`,
+                    content: `foo`
+                };
+                const sharedSymlink: SymLink = {
+                    path: `${tscWatch.projectRoot}/node_modules/shared`,
+                    symLink: `${tscWatch.projectRoot}/shared`
+                };
+                const files = [solnConfig, sharedConfig, sharedIndex, sharedPackage, appConfig, appBar, appIndex, sharedSymlink, libFile];
+                const host = createServerHost(files);
+                if (built) {
+                    const solutionBuilder = tscWatch.createSolutionBuilder(host, [solnConfig.path], {});
+                    solutionBuilder.build();
+                    host.clearOutput();
+                }
+                const session = createSession(host);
+                openFilesForSession([appIndex], session);
+                const response = session.executeCommandSeq<protocol.CodeFixRequest>({
+                    command: protocol.CommandTypes.GetCodeFixes,
+                    arguments: {
+                        file: appIndex.path,
+                        startLine: 1,
+                        startOffset: 1,
+                        endLine: 1,
+                        endOffset: 4,
+                        errorCodes: [Diagnostics.Cannot_find_name_0.code],
+                    }
+                }).response as protocol.CodeFixAction[];
+                assert.deepEqual(response, [
+                    {
+                        fixName: "import",
+                        description: `Import 'foo' from module "shared"`,
+                        changes: [{
+                            fileName: appIndex.path,
+                            textChanges: [{
+                                start: { line: 1, offset: 1 },
+                                end: { line: 1, offset: 1 },
+                                newText: 'import { foo } from "shared";\n\n',
+                            }],
+                        }],
+                        commands: undefined,
+                        fixAllDescription: undefined,
+                        fixId: undefined
+                    }
+                ]);
+            }
+
+            it("when project is built", () => {
+                verifyAutoImport(/*built*/ true);
+            });
+            it("when project is not built", () => {
+                verifyAutoImport(/*built*/ false);
+            });
+            it("when disableSourceOfProjectReferenceRedirect is true", () => {
+                verifyAutoImport(/*built*/ true, /*disableSourceOfProjectReferenceRedirect*/ true);
+            });
+        });
     });
 }