fix(@angular/cli): update zoneless migration tool to handle ChangeDetectionStrategy.Eager

`ChangeDetectionStrategy.Default` is deprecated. This update ensures the zoneless migration tool correctly identifies, handles, and prompts for the new `ChangeDetectionStrategy.Eager` strategy in component metadata.

Author: alan-agius4

packages/angular/cli/src/commands/mcp/tools/onpush-zoneless-migration/migrate-single-file.ts

@@ -16,6 +16,8 @@ import { sendDebugMessage } from './send-debug-message';
 import { getImportSpecifier, loadTypescript } from './ts-utils';
 import type { MigrationResponse } from './types';
 
+const supportedStrategies: ReadonlySet<string> = new Set(['OnPush', 'Default', 'Eager']);
+
 export async function migrateSingleFile(
   sourceFile: SourceFile,
   extras: RequestHandlerExtra<ServerRequest, ServerNotification>,
@@ -31,7 +33,7 @@ export async function migrateSingleFile(
     return unsupportedZoneUseResponse;
   }
 
-  let detectedStrategy: 'OnPush' | 'Default' | undefined;
+  let detectedStrategy: string | undefined;
   let hasComponentDecorator = false;
 
   const componentSpecifier = await getImportSpecifier(sourceFile, '@angular/core', 'Component');
@@ -63,7 +65,7 @@ export async function migrateSingleFile(
                 prop.initializer.expression.getText(sourceFile) === 'ChangeDetectionStrategy'
               ) {
                 const strategy = prop.initializer.name.text;
-                if (strategy === 'OnPush' || strategy === 'Default') {
+                if (supportedStrategies.has(strategy)) {
                   detectedStrategy = strategy;
 
                   return;
@@ -77,13 +79,7 @@ export async function migrateSingleFile(
     ts.forEachChild(node, visit);
   });
 
-  if (
-    !hasComponentDecorator ||
-    // component uses OnPush. We don't have anything more to do here.
-    detectedStrategy === 'OnPush' ||
-    // Explicit default strategy, assume there's a reason for it (already migrated, or is a library that hosts Default components) and skip.
-    detectedStrategy === 'Default'
-  ) {
+  if (!hasComponentDecorator || (detectedStrategy && supportedStrategies.has(detectedStrategy))) {
     sendDebugMessage(
       `Component decorator found with strategy: ${detectedStrategy} in file: ${sourceFile.fileName}. Skipping migration for file.`,
       extras,

packages/angular/cli/src/commands/mcp/tools/onpush-zoneless-migration/migrate-single-file_spec.ts

@@ -85,15 +85,15 @@ describe('migrateSingleFile', () => {
     expect(result).toBeNull();
   });
 
-  it('should return null if component has ChangeDetectionStrategy.Default', async () => {
+  it('should return null if component has ChangeDetectionStrategy.Eager', async () => {
     const fileName = 'app.component.ts';
     const content = `
       import { Component, ChangeDetectionStrategy } from '@angular/core';
 
       @Component({
         selector: 'app-root',
         template: 'Hello',
-        changeDetection: ChangeDetectionStrategy.Default,
+        changeDetection: ChangeDetectionStrategy.Eager,
       })
       export class AppComponent {}
     `;

packages/angular/cli/src/commands/mcp/tools/onpush-zoneless-migration/prompts.ts

@@ -130,11 +130,11 @@ export function generateZonelessMigrationInstructionsForComponent(
     *   **(Preferred) Convert to Signal**: The best approach is to convert the property to an Angular Signal. This is the most idiomatic and future-proof way to handle state in zoneless applications.
     *   **(Alternative) Use \`markForCheck()\`**: If converting to a signal is too complex or would require extensive refactoring, you can instead inject \`ChangeDetectorRef\` and call \`this.cdr.markForCheck()\` immediately after the property is updated.
 
-  #### Step 2: Add \`ChangeDetectionStrategy.Default\`
+  #### Step 2: Add \`ChangeDetectionStrategy.Eager\`
   After you have refactored all necessary properties, you must update the component's decorator to explicitly set the change detection strategy.
 
   1.  Add \`ChangeDetectionStrategy\` to the import from \`@angular/core\`.
-  2.  In the \`@Component\` decorator, add the property \`changeDetection: ChangeDetectionStrategy.Default\`.
+  2.  In the \`@Component\` decorator, add the property \`changeDetection: ChangeDetectionStrategy.Eager\`.
   3.  Add a \`// TODO\` comment above this line explaining that the component should be fully migrated to \`OnPush\` after the application has been tested with these changes.
 
   Example:
@@ -143,14 +143,14 @@ export function generateZonelessMigrationInstructionsForComponent(
     ...
     // TODO: This component has been partially migrated to be zoneless-compatible.
     // After testing, this should be updated to ChangeDetectionStrategy.OnPush.
-    changeDetection: ChangeDetectionStrategy.Default,
+    changeDetection: ChangeDetectionStrategy.Eager,
   })
   \`\`\`
 
   ### IMPORTANT: Rules and Constraints
   You must follow these rules without exception:
   1.  **DO** apply one of the two refactoring strategies (signals or \`markForCheck()\`) for all relevant component properties.
-  2.  **DO** add \`changeDetection: ChangeDetectionStrategy.Default\` with the specified TODO comment as the final code change.
+  2.  **DO** add \`changeDetection: ChangeDetectionStrategy.Eager\` with the specified TODO comment as the final code change.
   3.  **DO NOT** use \`ChangeDetectionStrategy.OnPush\`. This will be the next step in the migration, but it is not part of this task.
   4.  **DO NOT** modify properties that are already signals or are used with the \`async\` pipe in the template, as they are already zoneless-compatible.
   5.  **DO NOT** make any changes to files other than the component file at \`${filePath}\` and its direct template/style files if necessary.

packages/angular/cli/src/commands/mcp/tools/onpush-zoneless-migration/zoneless-migration.ts

@@ -204,8 +204,7 @@ async function categorizeFile(
     componentTestFiles.add(sourceFile);
   } else if (componentSpecifier) {
     if (
-      !content.includes('changeDetectionStrategy: ChangeDetectionStrategy.OnPush') &&
-      !content.includes('changeDetectionStrategy: ChangeDetectionStrategy.Default')
+      !/changeDetectionStrategy:\s*ChangeDetectionStrategy\.(?:OnPush|Default|Eager)/.test(content)
     ) {
       filesWithComponents.add(sourceFile);
     } else {