Always include parent folder failed lookup locations

Author: RyanCavanaugh

src/compiler/moduleNameResolver.ts

@@ -1118,7 +1118,7 @@ namespace ts {
         const perModuleNameCache = cache && cache.getOrCreateCacheForModuleName(moduleName);
         return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
             if (getBaseFileName(ancestorDirectory) !== "node_modules") {
-                const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, ancestorDirectory, state.traceEnabled, state.host);
+                const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, ancestorDirectory, state.traceEnabled, state.host, failedLookupLocations);
                 if (resolutionFromCache) {
                     return resolutionFromCache;
                 }
@@ -1196,12 +1196,13 @@ namespace ts {
             typesPackageName;
     }
 
-    function tryFindNonRelativeModuleNameInCache(cache: PerModuleNameCache | undefined, moduleName: string, containingDirectory: string, traceEnabled: boolean, host: ModuleResolutionHost): SearchResult<Resolved> {
+    function tryFindNonRelativeModuleNameInCache(cache: PerModuleNameCache | undefined, moduleName: string, containingDirectory: string, traceEnabled: boolean, host: ModuleResolutionHost, failedLookupLocations: Push<string>): SearchResult<Resolved> {
         const result = cache && cache.get(containingDirectory);
         if (result) {
             if (traceEnabled) {
                 trace(host, Diagnostics.Resolution_for_module_0_was_found_in_cache_from_location_1, moduleName, containingDirectory);
             }
+            failedLookupLocations.push(...result.failedLookupLocations);
             return { value: result.resolvedModule && { path: result.resolvedModule.resolvedFileName, extension: result.resolvedModule.extension, packageId: result.resolvedModule.packageId } };
         }
     }
@@ -1226,7 +1227,7 @@ namespace ts {
             if (!isExternalModuleNameRelative(moduleName)) {
                 // Climb up parent directories looking for a module.
                 const resolved = forEachAncestorDirectory(containingDirectory, directory => {
-                    const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, directory, traceEnabled, host);
+                    const resolutionFromCache = tryFindNonRelativeModuleNameInCache(perModuleNameCache, moduleName, directory, traceEnabled, host, failedLookupLocations);
                     if (resolutionFromCache) {
                         return resolutionFromCache;
                     }

src/harness/unittests/moduleResolution.ts

@@ -16,7 +16,7 @@ namespace ts {
     export function checkResolvedModuleWithFailedLookupLocations(actual: ResolvedModuleWithFailedLookupLocations, expectedResolvedModule: ResolvedModuleFull, expectedFailedLookupLocations: string[]): void {
         assert.isTrue(actual.resolvedModule !== undefined, "module should be resolved");
         checkResolvedModule(actual.resolvedModule, expectedResolvedModule);
-        assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations);
+        assert.deepEqual(actual.failedLookupLocations, expectedFailedLookupLocations, `Failed lookup locations should match - expected has ${expectedFailedLookupLocations.length}, actual has ${actual.failedLookupLocations.length}`);
     }
 
     export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport = false): ResolvedModuleFull {

src/harness/unittests/tsserverProjectSystem.ts

@@ -6045,6 +6045,47 @@ namespace ts.projectSystem {
             });
         });
 
+        describe("Subfolder invalidations correctly include parent folder failed lookup locations QJWOP", () => {
+            it("Includes the parent folder FLLs", () => {
+                const projectLocation = "/proj";
+                const file1: FileOrFolder = {
+                    path: `${projectLocation}/foo/boo/app.ts`,
+                    content: `import * as debug from "debug"`
+                };
+                const file2: FileOrFolder = {
+                    path: `${projectLocation}/foo/boo/moo/app.ts`,
+                    content: `import * as debug from "debug"`
+                };
+                const tsconfig: FileOrFolder = {
+                    path: `${projectLocation}/tsconfig.json`,
+                    content: JSON.stringify({
+                        files: ["foo/boo/app.ts", "foo/boo/moo/app.ts"]
+                    })
+                };
+
+                const files = [file1, file2, tsconfig, libFile];
+                const host = createServerHost(files);
+                const service = createProjectService(host);
+                service.openClientFile(file1.path);
+
+                const project = service.configuredProjects.get(tsconfig.path);
+                checkProjectActualFiles(project, files.map(f => f.path));
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file1.path).map(diag => diag.messageText), ["Cannot find module 'debug'."]);
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file2.path).map(diag => diag.messageText), ["Cannot find module 'debug'."]);
+
+                const debugTypesFile: FileOrFolder = {
+                    path: `${projectLocation}/node_modules/debug/index.d.ts`,
+                    content: "export {}"
+                };
+                files.push(debugTypesFile);
+                host.reloadFS(files);
+                host.runQueuedTimeoutCallbacks();
+                checkProjectActualFiles(project, files.map(f => f.path));
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file1.path).map(diag => diag.messageText), []);
+                assert.deepEqual(project.getLanguageService().getSemanticDiagnostics(file2.path).map(diag => diag.messageText), []);
+            });
+        });
+
         describe("Verify npm install in directory with tsconfig file works when", () => {
             function verifyNpmInstall(timeoutDuringPartialInstallation: boolean) {
                 const root = "/user/username/rootfolder/otherfolder";