fix(compiler-cli): do not persist component analysis if template/styles are missing (#49184)

devversion · AndrewKushnir · commit b6c6dfd27818 · 2023-02-24T08:24:07.000-08:00
Consider the following scenario: 1. A TS file with a component and templateUrl exists 2. The template file does not exist. 3. First build: ngtsc will properly report the error, via a FatalDiagnosticError 4. The template file is now created 5. Second build: ngtsc still reports the same errror. ngtsc persists the analysis data of the component and never invalidates it when the template/style file becomes available later. This breaks incremental builds and potentially common workflows where resource files are added later after the TS file is created. This did surface as an issue in the Angular CLI yet because Webpack requires users to re-start the process when a new file is added. With ESBuild this will change and this also breaks incremental builds with Bazel/Blaze workers. To fix this, we have a few options: * Invalidate the analysis when e.g. the template file is missing. Never caching it means that it will be re-analyzed on every build iteration. * Add the resource dependency to ngtsc's incremental file graph. ngtsc will then know via `host.getModifiedResources` when the file becomes available- and fresh analysis of component would occur. The first approach is straightforward to implement and was chosen here. The second approach would allow ngtsc to re-use more of the analysis when we know that e.g. the template file still not there, but it increases complexity unnecessarily because there is no **single** obvious resource path for e.g. a `templateUrl`. The URL is attempted to be resolved using multiple strategies, such as TS program root dirs, or there is support for a custom resolution through `host.resourceNameToFileName`. It would be possible to determine some candidate paths and add them to the dependency tracker, but it seems incomplete given possible external resolvers like `resourceNameToFileName` and also would likely not have a sufficient-enough impact given that a broken component decorator is not expected to remain for too long between N incremental build iterations. PR Close #49184
diff --git a/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts b/packages/compiler-cli/src/ngtsc/annotations/component/src/handler.ts
@@ -318,8 +318,8 @@ export class ComponentDecoratorHandler implements
       template = preanalyzed;
     } else {
       const templateDecl = parseTemplateDeclaration(
-          decorator, component, containingFile, this.evaluator, this.resourceLoader,
-          this.defaultPreserveWhitespaces);
+          node, decorator, component, containingFile, this.evaluator, this.depTracker,
+          this.resourceLoader, this.defaultPreserveWhitespaces);
       template = extractTemplate(
           node, templateDecl, this.evaluator, this.depTracker, this.resourceLoader, {
             enableI18nLegacyMessageIdFormat: this.enableI18nLegacyMessageIdFormat,
@@ -353,6 +353,13 @@ export class ComponentDecoratorHandler implements
           this.depTracker.addResourceDependency(node.getSourceFile(), absoluteFrom(resourceUrl));
         }
       } catch {
+        if (this.depTracker !== null) {
+          // The analysis of this file cannot be re-used if one of the style URLs could
+          // not be resolved or loaded. Future builds should re-analyze and re-attempt
+          // resolution/loading.
+          this.depTracker.recordDependencyAnalysisFailure(node.getSourceFile());
+        }
+
         if (diagnostics === undefined) {
           diagnostics = [];
         }
diff --git a/packages/compiler-cli/src/ngtsc/annotations/component/src/resources.ts b/packages/compiler-cli/src/ngtsc/annotations/component/src/resources.ts
@@ -262,9 +262,9 @@ function parseExtractedTemplate(
 }
 
 export function parseTemplateDeclaration(
-    decorator: Decorator, component: Map<string, ts.Expression>, containingFile: string,
-    evaluator: PartialEvaluator, resourceLoader: ResourceLoader,
-    defaultPreserveWhitespaces: boolean): TemplateDeclaration {
+    node: ClassDeclaration, decorator: Decorator, component: Map<string, ts.Expression>,
+    containingFile: string, evaluator: PartialEvaluator, depTracker: DependencyTracker|null,
+    resourceLoader: ResourceLoader, defaultPreserveWhitespaces: boolean): TemplateDeclaration {
   let preserveWhitespaces: boolean = defaultPreserveWhitespaces;
   if (component.has('preserveWhitespaces')) {
     const expr = component.get('preserveWhitespaces')!;
@@ -305,6 +305,12 @@ export function parseTemplateDeclaration(
         resolvedTemplateUrl: resourceUrl,
       };
     } catch (e) {
+      if (depTracker !== null) {
+        // The analysis of this file cannot be re-used if the template URL could
+        // not be resolved. Future builds should re-analyze and re-attempt resolution.
+        depTracker.recordDependencyAnalysisFailure(node.getSourceFile());
+      }
+
       throw makeResourceNotFoundError(
           templateUrl, templateUrlExpr, ResourceTypeForDiagnostics.Template);
     }
@@ -348,7 +354,7 @@ export function preloadAndParseTemplate(
       if (templatePromise !== undefined) {
         return templatePromise.then(() => {
           const templateDecl = parseTemplateDeclaration(
-              decorator, component, containingFile, evaluator, resourceLoader,
+              node, decorator, component, containingFile, evaluator, depTracker, resourceLoader,
               defaultPreserveWhitespaces);
           const template =
               extractTemplate(node, templateDecl, evaluator, depTracker, resourceLoader, options);
@@ -359,12 +365,18 @@ export function preloadAndParseTemplate(
         return Promise.resolve(null);
       }
     } catch (e) {
+      if (depTracker !== null) {
+        // The analysis of this file cannot be re-used if the template URL could
+        // not be resolved. Future builds should re-analyze and re-attempt resolution.
+        depTracker.recordDependencyAnalysisFailure(node.getSourceFile());
+      }
+
       throw makeResourceNotFoundError(
           templateUrl, templateUrlExpr, ResourceTypeForDiagnostics.Template);
     }
   } else {
     const templateDecl = parseTemplateDeclaration(
-        decorator, component, containingFile, evaluator, resourceLoader,
+        node, decorator, component, containingFile, evaluator, depTracker, resourceLoader,
         defaultPreserveWhitespaces);
     const template =
         extractTemplate(node, templateDecl, evaluator, depTracker, resourceLoader, options);
diff --git a/packages/compiler-cli/test/ngtsc/incremental_spec.ts b/packages/compiler-cli/test/ngtsc/incremental_spec.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
+import {ErrorCode, ngErrorCode} from '../../src/ngtsc/diagnostics';
 import {runInEachFileSystem} from '../../src/ngtsc/file_system/testing';
 import {loadStandardTestFiles} from '../../src/ngtsc/testing';
 
@@ -945,6 +946,50 @@ runInEachFileSystem(() => {
         });
       });
     });
+
+    describe('missing resource files', () => {
+      it('should re-analyze a component if a template file becomes available later', () => {
+        env.write('app.ts', `
+        import {Component} from '@angular/core';
+
+        @Component({
+          selector: 'app',
+          templateUrl: './some-template.html',
+        })
+        export class AppComponent {}
+      `);
+
+        const firstDiagnostics = env.driveDiagnostics();
+        expect(firstDiagnostics.length).toBe(1);
+        expect(firstDiagnostics[0].code).toBe(ngErrorCode(ErrorCode.COMPONENT_RESOURCE_NOT_FOUND));
+
+        env.write('some-template.html', `
+          <span>Test</span>
+        `);
+
+        env.driveMain();
+      });
+
+      it('should re-analyze if component style file becomes available later', () => {
+        env.write('app.ts', `
+        import {Component} from '@angular/core';
+
+        @Component({
+          selector: 'app',
+          template: 'Works',
+          styleUrls: ['./some-style.css'],
+        })
+        export class AppComponent {}
+      `);
+
+        const firstDiagnostics = env.driveDiagnostics();
+        expect(firstDiagnostics.length).toBe(1);
+        expect(firstDiagnostics[0].code).toBe(ngErrorCode(ErrorCode.COMPONENT_RESOURCE_NOT_FOUND));
+
+        env.write('some-style.css', `body {}`);
+        env.driveMain();
+      });
+    });
   });
 
   function setupFooBarProgram(env: NgtscTestEnvironment) {
