fix(compiler-cli): diagnostics should respect "newLine" compiler option (#28352)

PR Close #28352

packages/compiler-cli/src/main.ts

@@ -166,17 +166,32 @@ export function readCommandLineAndConfiguration(
   };
 }
 
+function getFormatDiagnosticsHost(options?: api.CompilerOptions): ts.FormatDiagnosticsHost {
+  const basePath = options ? options.basePath : undefined;
+  return {
+    getCurrentDirectory: () => basePath || ts.sys.getCurrentDirectory(),
+    // We need to normalize the path separators here because by default, TypeScript
+    // compiler hosts use posix canonical paths. In order to print consistent diagnostics,
+    // we also normalize the paths.
+    getCanonicalFileName: fileName => fileName.replace(/\\/g, '/'),
+    getNewLine: () => {
+      // Manually determine the proper new line string based on the passed compiler
+      // options. There is no public TypeScript function that returns the corresponding
+      // new line string. see: https://github.com/Microsoft/TypeScript/issues/29581
+      if (options && options.newLine !== undefined) {
+        return options.newLine === ts.NewLineKind.LineFeed ? '\n' : '\r\n';
+      }
+      return ts.sys.newLine;
+    },
+  };
+}
+
 function reportErrorsAndExit(
     allDiagnostics: Diagnostics, options?: api.CompilerOptions,
     consoleError: (s: string) => void = console.error): number {
   const errorsAndWarnings = filterErrorsAndWarnings(allDiagnostics);
   if (errorsAndWarnings.length) {
-    let currentDir = options ? options.basePath : undefined;
+    const formatHost = getFormatDiagnosticsHost(options);
-    const formatHost: ts.FormatDiagnosticsHost = {
-      getCurrentDirectory: () => currentDir || ts.sys.getCurrentDirectory(),
-      getCanonicalFileName: fileName => fileName,
-      getNewLine: () => ts.sys.newLine
-    };
     if (options && (options.enableIvy === true || options.enableIvy === 'ngtsc')) {
       const ngDiagnostics = errorsAndWarnings.filter(api.isNgDiagnostic);
       const tsDiagnostics = errorsAndWarnings.filter(api.isTsDiagnostic);
@@ -193,7 +208,7 @@ function reportErrorsAndExit(
 export function watchMode(
     project: string, options: api.CompilerOptions, consoleError: (s: string) => void) {
   return performWatchCompilation(createPerformWatchHost(project, diagnostics => {
-    consoleError(formatDiagnostics(diagnostics));
+    consoleError(formatDiagnostics(diagnostics, getFormatDiagnosticsHost(options)));
   }, options, options => createEmitCallback(options)));
 }
 

packages/compiler-cli/test/ngc_spec.ts

@@ -99,6 +99,25 @@ describe('ngc transformer command-line', () => {
     expect(exitCode).toBe(0);
   });
 
+  it('should respect the "newLine" compiler option when printing diagnostics', () => {
+    writeConfig(`{
+      "extends": "./tsconfig-base.json",
+      "compilerOptions": {
+        "newLine": "CRLF",
+      }
+    }`);
+    write('test.ts', 'export NOT_VALID = true;');
+
+    // Stub the error spy because we don't want to call through and print the
+    // expected error diagnostic.
+    errorSpy.and.stub();
+
+    const exitCode = main(['-p', basePath], errorSpy);
+    expect(errorSpy).toHaveBeenCalledWith(
+        `test.ts(1,1): error TS1128: Declaration or statement expected.\r\n`);
+    expect(exitCode).toBe(1);
+  });
+
   describe('errors', () => {
 
     beforeEach(() => { errorSpy.and.stub(); });