fix(language-service): diagnostic and definition should work for absolute url (#40406)

This commit fixes a bug in the **View Engine** implementation of
`getSemanticDiagnostics` and `getDefinitionAndBoundSpan` for node in the
decorator metadata that represents an external URL
(`templateUrl` or `styleUrls`).

The URL could be either relative or absolute, but the latter was not taken
into account.

Fix https://github.com/angular/vscode-ng-language-service/issues/1055

PR Close #40406

packages/language-service/src/definitions.ts

@@ -6,12 +6,12 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import * as path from 'path';
 import * as ts from 'typescript';  // used as value and is provided at runtime
 
 import {locateSymbols} from './locate_symbol';
 import {findTightestNode, getClassDeclFromDecoratorProp, getPropertyAssignmentFromValue} from './ts_utils';
 import {AstResult, Span} from './types';
+import {extractAbsoluteFilePath} from './utils';
 
 /**
  * Convert Angular Span to TypeScript TextSpan. Angular Span has 'start' and
@@ -59,10 +59,9 @@ function getUrlFromProperty(
     return;
   }
 
-  const sf = urlNode.getSourceFile();
   // Extract url path specified by the url node, which is relative to the TypeScript source file
   // the url node is defined in.
-  const url = path.join(path.dirname(sf.fileName), urlNode.text);
+  const url = extractAbsoluteFilePath(urlNode);
 
   // If the file does not exist, bail. It is possible that the TypeScript language service host
   // does not have a `fileExists` method, in which case optimistically assume the file exists.

packages/language-service/src/diagnostics.ts

@@ -7,7 +7,6 @@
  */
 
 import {NgAnalyzedModules} from '@angular/compiler';
-import * as path from 'path';
 import * as ts from 'typescript';
 
 import {createDiagnostic, Diagnostic} from './diagnostic_messages';
@@ -15,7 +14,7 @@ import {getTemplateExpressionDiagnostics} from './expression_diagnostics';
 import {findPropertyValueOfType, findTightestNode} from './ts_utils';
 import * as ng from './types';
 import {TypeScriptServiceHost} from './typescript_host';
-import {offsetSpan, spanOf} from './utils';
+import {extractAbsoluteFilePath, offsetSpan, spanOf} from './utils';
 
 /**
  * Return diagnostic information for the parsed AST of the template.
@@ -161,8 +160,8 @@ function validateUrls(
       // picked up by the TS Language Server.
       continue;
     }
-    const curPath = urlNode.getSourceFile().fileName;
-    const url = path.join(path.dirname(curPath), urlNode.text);
+
+    const url = extractAbsoluteFilePath(urlNode);
     if (tsLsHost.fileExists(url)) continue;
 
     // Exclude opening and closing quotes in the url span.

packages/language-service/src/utils.ts

@@ -7,7 +7,8 @@
  */
 
 import {AstPath, BoundEventAst, CompileDirectiveSummary, CompileTypeMetadata, CssSelector, DirectiveAst, ElementAst, EmbeddedTemplateAst, HtmlAstPath, identifierName, Identifiers, Node, ParseSourceSpan, RecursiveTemplateAstVisitor, RecursiveVisitor, TemplateAst, TemplateAstPath, templateVisitAll, visitAll} from '@angular/compiler';
-import {getClassDeclFromDecoratorProp, getPropertyAssignmentFromValue} from './ts_utils';
+import * as path from 'path';
+
 import {AstResult, DiagnosticTemplateInfo, SelectorInfo, Span, Symbol, SymbolQuery} from './types';
 
 interface SpanHolder {
@@ -204,3 +205,13 @@ export function findOutputBinding(
     }
   }
 }
+
+/**
+ * Returns an absolute path from the text in `node`. If the text is already
+ * an absolute path, return it as is, otherwise join the path with the filename
+ * of the source file.
+ */
+export function extractAbsoluteFilePath(node: ts.StringLiteralLike) {
+  const url = node.text;
+  return path.isAbsolute(url) ? url : path.join(path.dirname(node.getSourceFile().fileName), url);
+}

packages/language-service/test/definitions_spec.ts

@@ -420,6 +420,19 @@ describe('definitions', () => {
     expect(def.textSpan).toEqual({start: 0, length: 0});
   });
 
+  it('should be able to find a template from an absolute url', () => {
+    const fileName = mockHost.addCode(`
+      @Component({
+        templateUrl: '${TEST_TEMPLATE}',
+      })
+      export class MyComponent {}`);
+
+    const marker = mockHost.readFile(fileName)!.indexOf(TEST_TEMPLATE);
+    const result = ngService.getDefinitionAndBoundSpan(fileName, marker);
+
+    expect(result?.definitions?.[0].fileName).toBe(TEST_TEMPLATE);
+  });
+
   it('should be able to find a stylesheet from a url', () => {
     const fileName = mockHost.addCode(`
 	      @Component({

packages/language-service/test/diagnostics_spec.ts

@@ -89,6 +89,19 @@ describe('diagnostics', () => {
     }
   });
 
+  it('should not produce diagnostics for absolute template url', () => {
+    mockHost.override(APP_COMPONENT, `
+      import {Component} from '@angular/core';
+
+      @Component({
+        templateUrl: '${TEST_TEMPLATE}',
+      })
+      export class AppComponent {}
+    `);
+    const diags = ngLS.getSemanticDiagnostics(APP_COMPONENT);
+    expect(diags).toEqual([]);
+  });
+
   it('should not produce diagnostics for slice pipe with arguments', () => {
     mockHost.override(TEST_TEMPLATE, `
       <div *ngFor="let h of heroes | slice:0:1">