Fix the invalid file/directory location when getting file system entry for caching read directory results

Fixes #20607

Author: sheetalkamat

src/compiler/core.ts

@@ -20,6 +20,7 @@ namespace ts {
 
 /* @internal */
 namespace ts {
+    export const emptyArray: never[] = [] as never[];
     /** Create a MapLike with good performance. */
     function createDictionaryObject<T>(): MapLike<T> {
         const map = Object.create(/*prototype*/ null); // tslint:disable-line:no-null-keyword
@@ -3069,6 +3070,10 @@ namespace ts {
         readonly directories: string[];
     }
 
+    export const emptyFileSystemEntries: FileSystemEntries = {
+        files: emptyArray,
+        directories: emptyArray
+    };
     export function createCachedDirectoryStructureHost(host: DirectoryStructureHost): CachedDirectoryStructureHost {
         const cachedReadDirectoryResult = createMap<MutableFileSystemEntries>();
         const getCurrentDirectory = memoize(() => host.getCurrentDirectory());
@@ -3210,7 +3215,7 @@ namespace ts {
                 if (path === rootDirPath) {
                     return result;
                 }
-                return getCachedFileSystemEntries(path) || createCachedFileSystemEntries(dir, path);
+                return tryReadDirectory(dir, path) || emptyFileSystemEntries;
             }
         }
 

src/compiler/sys.ts

@@ -398,7 +398,7 @@ namespace ts {
                     return { files, directories };
                 }
                 catch (e) {
-                    return { files: [], directories: [] };
+                    return emptyFileSystemEntries;
                 }
             }
 

src/compiler/utilities.ts

@@ -2,7 +2,6 @@
 
 /* @internal */
 namespace ts {
-    export const emptyArray: never[] = [] as never[];
     export const resolvingEmptyArray: never[] = [] as never[];
     export const emptyMap: ReadonlyMap<never> = createMap<never>();
     export const emptyUnderscoreEscapedMap: ReadonlyUnderscoreEscapedMap<never> = emptyMap as ReadonlyUnderscoreEscapedMap<never>;

src/harness/unittests/tsserverProjectSystem.ts

@@ -4168,6 +4168,32 @@ namespace ts.projectSystem {
             // Since no file from the configured project is open, it would be closed immediately
             projectService.checkNumberOfProjects({ configuredProjects: 0, inferredProjects: 1 });
         });
+
+        it("should tolerate invalid include files that start in subDirectory", () => {
+            const projectFolder = "/user/username/projects/myproject";
+            const f = {
+                path: `${projectFolder}/src/server/index.ts`,
+                content: "let x = 1"
+            };
+            const config = {
+                path: `${projectFolder}/src/server/tsconfig.json`,
+                content: JSON.stringify({
+                    compiler: {
+                        module: "commonjs",
+                        outDir: "../../build"
+                    },
+                    include: [
+                        "../src/**/*.ts"
+                    ]
+                })
+            };
+            const host = createServerHost([f, config, libFile], { useCaseSensitiveFileNames: true });
+            const projectService = createProjectService(host);
+
+            projectService.openClientFile(f.path);
+            // Since no file from the configured project is open, it would be closed immediately
+            projectService.checkNumberOfProjects({ configuredProjects: 0, inferredProjects: 1 });
+        });
     });
 
     describe("tsserverProjectSystem reload", () => {