Fix missing file name of extended source file in synchronizeProjectList when it is missing on disk (#41222)

Fixes #40136

Author: sheetalkamat

src/compiler/commandLineParser.ts

@@ -1578,7 +1578,7 @@ namespace ts {
      */
     export function readJsonConfigFile(fileName: string, readFile: (path: string) => string | undefined): TsConfigSourceFile {
         const textOrDiagnostic = tryReadFile(fileName, readFile);
-        return isString(textOrDiagnostic) ? parseJsonText(fileName, textOrDiagnostic) : <TsConfigSourceFile>{ parseDiagnostics: [textOrDiagnostic] };
+        return isString(textOrDiagnostic) ? parseJsonText(fileName, textOrDiagnostic) : <TsConfigSourceFile>{ fileName, parseDiagnostics: [textOrDiagnostic] };
     }
 
     /*@internal*/

src/testRunner/unittests/tsserver/projects.ts

@@ -1481,6 +1481,48 @@ namespace ts.projectSystem {
             ]);
         });
 
+        it("synchronizeProjectList returns correct information when base configuration file cannot be resolved", () => {
+            const file: File = {
+                path: `${tscWatch.projectRoot}/index.ts`,
+                content: "export const foo = 5;"
+            };
+            const config: File = {
+                path: `${tscWatch.projectRoot}/tsconfig.json`,
+                content: JSON.stringify({ extends: "./tsconfig_base.json" })
+            };
+            const host = createServerHost([file, config, libFile]);
+            const projectService = createProjectService(host);
+            projectService.openClientFile(file.path);
+            const knownProjects = projectService.synchronizeProjectList([], /*includeProjectReferenceRedirectInfo*/ false);
+            assert.deepEqual(knownProjects[0].files, [
+                libFile.path,
+                file.path,
+                config.path,
+                `${tscWatch.projectRoot}/tsconfig_base.json`,
+            ]);
+        });
+
+        it("synchronizeProjectList returns correct information when base configuration file cannot be resolved and redirect info is requested", () => {
+            const file: File = {
+                path: `${tscWatch.projectRoot}/index.ts`,
+                content: "export const foo = 5;"
+            };
+            const config: File = {
+                path: `${tscWatch.projectRoot}/tsconfig.json`,
+                content: JSON.stringify({ extends: "./tsconfig_base.json" })
+            };
+            const host = createServerHost([file, config, libFile]);
+            const projectService = createProjectService(host);
+            projectService.openClientFile(file.path);
+            const knownProjects = projectService.synchronizeProjectList([], /*includeProjectReferenceRedirectInfo*/ true);
+            assert.deepEqual(knownProjects[0].files, [
+                { fileName: libFile.path, isSourceOfProjectReferenceRedirect: false },
+                { fileName: file.path, isSourceOfProjectReferenceRedirect: false },
+                { fileName: config.path, isSourceOfProjectReferenceRedirect: false },
+                { fileName: `${tscWatch.projectRoot}/tsconfig_base.json`, isSourceOfProjectReferenceRedirect: false },
+            ]);
+        });
+
         it("handles delayed directory watch invoke on file creation", () => {
             const projectRootPath = "/users/username/projects/project";
             const fileB: File = {