angular
diff --git a/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/karma-processor.ts‎
Lines changed: 28 additions & 22 deletions b/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/karma-processor.ts‎
Lines changed: 28 additions & 22 deletions
diff --git a/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/migration.ts‎
Lines changed: 10 additions & 3 deletions b/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/migration.ts‎
Lines changed: 10 additions & 3 deletions
diff --git a/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/migration_spec.ts‎
Lines changed: 60 additions & 0 deletions b/‎packages/schematics/angular/migrations/migrate-karma-to-vitest/migration_spec.ts‎
Lines changed: 60 additions & 0 deletions
@@ -119,42 +119,47 @@ function extractCoverageSettings(
   }
 }
 
+export interface KarmaConfigProcessingResult {
+  analysis: KarmaConfigAnalysis;
+  isRemovable: boolean;
+}
+
 export async function processKarmaConfig(
   karmaConfig: string,
   options: Record<string, json.JsonValue | undefined>,
   projectName: string,
   context: SchematicContext,
   tree: Tree,
-  removableKarmaConfigs: Map<string, boolean>,
+  cache: Map<string, KarmaConfigProcessingResult>,
   needDevkitPlugin: boolean,
   manualMigrationFiles: string[],
 ): Promise<void> {
-  if (tree.exists(karmaConfig)) {
+  let cachedResult = cache.get(karmaConfig);
+
+  if (!cachedResult && tree.exists(karmaConfig)) {
     const content = tree.readText(karmaConfig);
     const analysis = analyzeKarmaConfig(content);
 
-    extractReporters(analysis, options, projectName, context);
-    extractCoverageSettings(analysis, options, projectName, context);
-
-    let isRemovable = removableKarmaConfigs.get(karmaConfig);
-    if (isRemovable === undefined) {
-      if (analysis.hasUnsupportedValues) {
-        isRemovable = false;
-      } else {
-        const diff = await compareKarmaConfigToDefault(
-          analysis,
-          projectName,
-          karmaConfig,
-          needDevkitPlugin,
-        );
-        isRemovable = !hasDifferences(diff) && diff.isReliable;
-      }
-      removableKarmaConfigs.set(karmaConfig, isRemovable);
+    let isRemovable = false;
+    if (!analysis.hasUnsupportedValues) {
+      const diff = await compareKarmaConfigToDefault(
+        analysis,
+        projectName,
+        karmaConfig,
+        needDevkitPlugin,
+      );
+      isRemovable = !hasDifferences(diff) && diff.isReliable;
     }
 
-    if (isRemovable) {
-      tree.delete(karmaConfig);
-    } else {
+    cachedResult = { analysis, isRemovable };
+    cache.set(karmaConfig, cachedResult);
+  }
+
+  if (cachedResult) {
+    extractReporters(cachedResult.analysis, options, projectName, context);
+    extractCoverageSettings(cachedResult.analysis, options, projectName, context);
+
+    if (!cachedResult.isRemovable) {
       context.logger.warn(
         `Project "${projectName}" uses a custom Karma configuration file "${karmaConfig}". ` +
           `Tests have been migrated to use Vitest, but you may need to manually migrate custom settings ` +
@@ -164,5 +169,6 @@ export async function processKarmaConfig(
       manualMigrationFiles.push(karmaConfig);
     }
   }
+
   delete options['karmaConfig'];
 }
@@ -14,14 +14,14 @@ import { latestVersions } from '../../utility/latest-versions';
 import { TargetDefinition, allTargetOptions, updateWorkspace } from '../../utility/workspace';
 import { Builders } from '../../utility/workspace-models';
 import { BUILD_OPTIONS_KEYS } from './constants';
-import { processKarmaConfig } from './karma-processor';
+import { KarmaConfigProcessingResult, processKarmaConfig } from './karma-processor';
 
 async function processTestTargetOptions(
   testTarget: TargetDefinition,
   projectName: string,
   context: SchematicContext,
   tree: Tree,
-  removableKarmaConfigs: Map<string, boolean>,
+  removableKarmaConfigs: Map<string, KarmaConfigProcessingResult>,
   customBuildOptions: Record<string, Record<string, json.JsonValue | undefined>>,
   needDevkitPlugin: boolean,
   manualMigrationFiles: string[],
@@ -122,7 +122,7 @@ async function processTestTargetOptions(
 function updateProjects(tree: Tree, context: SchematicContext): Rule {
   return updateWorkspace(async (workspace) => {
     let needsCoverage = false;
-    const removableKarmaConfigs = new Map<string, boolean>();
+    const removableKarmaConfigs = new Map<string, KarmaConfigProcessingResult>();
     const migratedProjects: string[] = [];
     const skippedNonApplications: string[] = [];
     const skippedMissingAppBuilder: string[] = [];
@@ -235,6 +235,13 @@ function updateProjects(tree: Tree, context: SchematicContext): Rule {
       migratedProjects.push(projectName);
     }
 
+    // Perform cleanup of removable karma config files
+    for (const [configPath, result] of removableKarmaConfigs) {
+      if (result.isRemovable && tree.exists(configPath)) {
+        tree.delete(configPath);
+      }
+    }
+
     // Log summary
     context.logger.info('\n--- Karma to Vitest Migration Summary ---');
     context.logger.info(`Projects migrated: ${migratedProjects.length}`);
 
@@ -322,6 +322,7 @@ module.exports = function (config) {
     const newTree = await schematicRunner.runSchematic('migrate-karma-to-vitest', {}, tree);
     expect(newTree.exists('karma.conf.js')).toBeFalse();
   });
+
   it('should shift main compilation entry file directly into setupFiles array', async () => {
     const { projects } = tree.readJson('/angular.json') as any;
     projects.app.targets.test.options.main = 'src/test.ts';
@@ -333,6 +334,7 @@ module.exports = function (config) {
     expect(newProjects.app.targets.test.options.setupFiles).toEqual(['src/test.ts']);
     expect(newProjects.app.targets.test.options.main).toBeUndefined();
   });
+
   it('should generate unique testing configuration name preventing collision overwrites', async () => {
     const { projects } = tree.readJson('/angular.json') as any;
     projects.app.targets.build.configurations = {
@@ -350,6 +352,7 @@ module.exports = function (config) {
     ]);
     expect(newProjects.app.targets.test.options.buildTarget).toBe(':build:testing-2');
   });
+
   it('should inject @vitest/coverage-v8 whenever coverage presence is detected', async () => {
     const { projects } = tree.readJson('/angular.json') as any;
     projects.app.targets.test.options.codeCoverage = true;
@@ -360,4 +363,61 @@ module.exports = function (config) {
 
     expect(devDependencies['@vitest/coverage-v8']).toBe(latestVersions['@vitest/coverage-v8']);
   });
+
+  it('should successfully extract settings across multiple projects sharing the same removable karma config', async () => {
+    const { projects } = tree.readJson('/angular.json') as any;
+    projects.app.targets.test.builder = '@angular-devkit/build-angular:karma';
+
+    // Add a second project sharing the exact same configuration
+    projects.app2 = {
+      ...JSON.parse(JSON.stringify(projects.app)),
+      root: 'app2',
+    };
+
+    tree.overwrite('/angular.json', JSON.stringify({ version: 1, projects }));
+
+    const DEFAULT_KARMA_CONFIG = `
+module.exports = function (config) {
+  config.set({
+    basePath: '',
+    frameworks: ['jasmine', '@angular-devkit/build-angular'],
+    plugins: [
+      require('karma-jasmine'),
+      require('karma-chrome-launcher'),
+      require('karma-jasmine-html-reporter'),
+      require('karma-coverage'),
+      require('@angular-devkit/build-angular/plugins/karma')
+    ],
+    client: {
+      jasmine: {},
+    },
+    jasmineHtmlReporter: {
+      suppressAll: true
+    },
+    coverageReporter: {
+      dir: require('path').join(__dirname, './coverage/app'),
+      subdir: '.',
+      reporters: [
+        { type: 'html' },
+        { type: 'text-summary' }
+      ]
+    },
+    reporters: ['progress', 'kjhtml'],
+    browsers: ['Chrome'],
+    restartOnFileChange: true
+  });
+};
+`;
+    tree.create('karma.conf.js', DEFAULT_KARMA_CONFIG);
+
+    const newTree = await schematicRunner.runSchematic('migrate-karma-to-vitest', {}, tree);
+    const { projects: newProjects } = newTree.readJson('/angular.json') as any;
+
+    // Assert BOTH projects got the extraction logic mapped correctly
+    expect(newProjects.app.targets.test.options.reporters).toEqual(['default']);
+    expect(newProjects.app2.targets.test.options.reporters).toEqual(['default']);
+
+    // Assert that the deletion deferred successfully until BOTH extracted the data
+    expect(newTree.exists('karma.conf.js')).toBeFalse();
+  });
 });