fix(compiler-cli): Show template syntax errors in local compilation m…

…odified (#55855)

Currently the template syntax errors are extracted in the template type check phase. But in local compilation mode we skip the type check phase. As a result template syntax errors are not displayed. With this change we show the template syntax diagnostics in local mode.

PR Close #55855

packages/compiler-cli/src/ngtsc/annotations/component/BUILD.bazel

@@ -25,6 +25,7 @@ ts_library(
         "//packages/compiler-cli/src/ngtsc/reflection",
         "//packages/compiler-cli/src/ngtsc/scope",
         "//packages/compiler-cli/src/ngtsc/transform",
+        "//packages/compiler-cli/src/ngtsc/typecheck",
         "//packages/compiler-cli/src/ngtsc/typecheck/api",
         "//packages/compiler-cli/src/ngtsc/typecheck/extended/api",
         "//packages/compiler-cli/src/ngtsc/typecheck/template_semantics/api",

packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts

@@ -114,7 +114,7 @@ import {
   HandlerPrecedence,
   ResolveResult,
 } from '../../../transform';
-import {TypeCheckableDirectiveMeta, TypeCheckContext} from '../../../typecheck/api';
+import {TemplateId, TypeCheckableDirectiveMeta, TypeCheckContext} from '../../../typecheck/api';
 import {ExtendedTemplateChecker} from '../../../typecheck/extended/api';
 import {TemplateSemanticsChecker} from '../../../typecheck/template_semantics/api/api';
 import {getSourceFile} from '../../../util/src/typescript';
@@ -176,6 +176,7 @@ import {
   collectAnimationNames,
   validateAndFlattenComponentImports,
 } from './util';
+import {getTemplateDiagnostics} from '../../../typecheck';
 
 const EMPTY_ARRAY: any[] = [];
 
@@ -624,6 +625,25 @@ export class ComponentDecoratorHandler
         },
         this.compilationMode,
       );
+
+      if (
+        this.compilationMode === CompilationMode.LOCAL &&
+        template.errors &&
+        template.errors.length > 0
+      ) {
+        // Template errors are handled at the type check phase. But we skip this phase in local compilation mode. As a result we need to handle the errors now and add them to the diagnostics.
+        if (diagnostics === undefined) {
+          diagnostics = [];
+        }
+
+        diagnostics.push(
+          ...getTemplateDiagnostics(
+            template.errors,
+            '' as TemplateId, // Template ID is required as part of the template type check, mainly for mapping the template to its component class. But here we are generating the diagnostic outside of the type check context, and so we skip the template ID.
+            template.sourceMapping,
+          ),
+        );
+      }
     }
     const templateResource = template.declaration.isInline
       ? {path: null, expression: component.get('template')!}
@@ -1578,10 +1598,6 @@ export class ComponentDecoratorHandler
     resolution: Readonly<Partial<ComponentResolutionData>>,
     pool: ConstantPool,
   ): CompileResult[] {
-    if (analysis.template.errors !== null && analysis.template.errors.length > 0) {
-      return [];
-    }
-
     // In the local compilation mode we can only rely on the information available
     // within the `@Component.deferredImports` array, because in this mode compiler
     // doesn't have information on which dependencies belong to which defer blocks.

packages/compiler-cli/src/ngtsc/typecheck/index.ts

@@ -7,6 +7,6 @@
  */
 
 export {FileTypeCheckingData, TemplateTypeCheckerImpl} from './src/checker';
-export {TypeCheckContextImpl} from './src/context';
+export {TypeCheckContextImpl, getTemplateDiagnostics} from './src/context';
 export {TypeCheckShimGenerator} from './src/shim';
 export {typeCheckFilePath} from './src/type_check_file';

packages/compiler-cli/src/ngtsc/typecheck/src/context.ts

@@ -250,9 +250,7 @@ export class TypeCheckContextImpl implements TypeCheckContext {
     const templateDiagnostics: TemplateDiagnostic[] = [];
 
     if (parseErrors !== null) {
-      templateDiagnostics.push(
-        ...this.getTemplateDiagnostics(parseErrors, templateId, sourceMapping),
-      );
+      templateDiagnostics.push(...getTemplateDiagnostics(parseErrors, templateId, sourceMapping));
     }
 
     const boundTarget = binder.bind({template});
@@ -559,33 +557,33 @@ export class TypeCheckContextImpl implements TypeCheckContext {
 
     return this.fileMap.get(sfPath)!;
   }
+}
 
-  private getTemplateDiagnostics(
-    parseErrors: ParseError[],
-    templateId: TemplateId,
-    sourceMapping: TemplateSourceMapping,
-  ): TemplateDiagnostic[] {
-    return parseErrors.map((error) => {
-      const span = error.span;
-
-      if (span.start.offset === span.end.offset) {
-        // Template errors can contain zero-length spans, if the error occurs at a single point.
-        // However, TypeScript does not handle displaying a zero-length diagnostic very well, so
-        // increase the ending offset by 1 for such errors, to ensure the position is shown in the
-        // diagnostic.
-        span.end.offset++;
-      }
+export function getTemplateDiagnostics(
+  parseErrors: ParseError[],
+  templateId: TemplateId,
+  sourceMapping: TemplateSourceMapping,
+): TemplateDiagnostic[] {
+  return parseErrors.map((error) => {
+    const span = error.span;
+
+    if (span.start.offset === span.end.offset) {
+      // Template errors can contain zero-length spans, if the error occurs at a single point.
+      // However, TypeScript does not handle displaying a zero-length diagnostic very well, so
+      // increase the ending offset by 1 for such errors, to ensure the position is shown in the
+      // diagnostic.
+      span.end.offset++;
+    }
 
-      return makeTemplateDiagnostic(
-        templateId,
-        sourceMapping,
-        span,
-        ts.DiagnosticCategory.Error,
-        ngErrorCode(ErrorCode.TEMPLATE_PARSE_ERROR),
-        error.msg,
-      );
-    });
-  }
+    return makeTemplateDiagnostic(
+      templateId,
+      sourceMapping,
+      span,
+      ts.DiagnosticCategory.Error,
+      ngErrorCode(ErrorCode.TEMPLATE_PARSE_ERROR),
+      error.msg,
+    );
+  });
 }
 
 /**

packages/compiler-cli/test/ngtsc/local_compilation_spec.ts

@@ -2623,5 +2623,67 @@ runInEachFileSystem(() => {
         );
       });
     });
+
+    describe('template diagnostics', () => {
+      it('should show correct error message for syntatic template errors - case of inline template', () => {
+        env.write(
+          'test.ts',
+          `
+          import {Component} from '@angular/core';
+  
+          @Component({
+            template: '<span Hello! </span>',
+          })
+          export class Main {
+          }
+          `,
+        );
+
+        const errors = env.driveDiagnostics();
+
+        expect(errors.length).toBeGreaterThanOrEqual(1);
+
+        const {code, messageText} = errors[0];
+
+        expect(code).toBe(ngErrorCode(ErrorCode.TEMPLATE_PARSE_ERROR));
+
+        const text = ts.flattenDiagnosticMessageText(messageText, '\n');
+
+        expect(text).toContain('Opening tag "span" not terminated');
+      });
+
+      it('should show correct error message for syntatic template errors - case of external template', () => {
+        env.write(
+          'test.ts',
+          `
+          import {Component} from '@angular/core';
+  
+          @Component({
+            templateUrl: 'test.ng.html',
+          })
+          export class Main {
+          }
+          `,
+        );
+        env.write(
+          'test.ng.html',
+          `
+          <span Hello! </span>
+          `,
+        );
+
+        const errors = env.driveDiagnostics();
+
+        expect(errors.length).toBeGreaterThanOrEqual(1);
+
+        const {code, messageText} = errors[0];
+
+        expect(code).toBe(ngErrorCode(ErrorCode.TEMPLATE_PARSE_ERROR));
+
+        const text = ts.flattenDiagnosticMessageText(messageText, '\n');
+
+        expect(text).toContain('Opening tag "span" not terminated');
+      });
+    });
   });
 });