From 4493d7833a336acfa5d6c4671e1d649318e876d0 Mon Sep 17 00:00:00 2001
From: Raashish Aggarwal <94279692+raashish1601@users.noreply.github.com>
Date: Fri, 27 Mar 2026 18:24:39 +0530
Subject: [PATCH 1/3] fix(@schematics/angular): preserve workspace build
 version

---
 .../use-application-builder/migration.ts        |  6 +++++-
 .../use-application-builder/migration_spec.ts   | 17 +++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/packages/schematics/angular/migrations/use-application-builder/migration.ts b/packages/schematics/angular/migrations/use-application-builder/migration.ts
index b481c4f30034..9a0040ad9f1d 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration.ts
@@ -15,6 +15,7 @@ import {
   externalSchematic,
 } from '@angular-devkit/schematics';
 import { dirname, join } from 'node:path/posix';
+import { getPackageJsonDependency } from '../../utility/dependencies';
 import {
   DependencyType,
   ExistingBehavior,
@@ -270,8 +271,11 @@ function updateProjects(tree: Tree, context: SchematicContext) {
       }
 
       // Add direct @angular/build dependencies and remove @angular-devkit/build-angular
+      const buildDependency =
+        getPackageJsonDependency(tree, '@angular-devkit/build-angular') ??
+        getPackageJsonDependency(tree, '@angular/build');
       rules.push(
-        addDependency('@angular/build', latestVersions.DevkitBuildAngular, {
+        addDependency('@angular/build', buildDependency?.version ?? latestVersions.AngularBuild, {
           type: DependencyType.Dev,
           existing: ExistingBehavior.Replace,
         }),
diff --git a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
index fd10352c6eac..70730d73de5e 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
@@ -450,6 +450,23 @@ describe(`Migration to use the application builder`, () => {
     expect(devDependencies['postcss']).toBeUndefined();
   });
 
+  it('should reuse the installed builder version when migrating to "@angular/build"', async () => {
+    tree.overwrite(
+      '/package.json',
+      JSON.stringify({
+        devDependencies: {
+          '@angular-devkit/build-angular': '~18.2.20',
+        },
+      }),
+    );
+
+    const newTree = await schematicRunner.runSchematic(schematicName, {}, tree);
+
+    const { devDependencies } = JSON.parse(newTree.readContent('/package.json'));
+    expect(devDependencies['@angular/build']).toBe('~18.2.20');
+    expect(devDependencies['@angular-devkit/build-angular']).toBeUndefined();
+  });
+
   it('it should not add esModuleInterop and moduleResolution when module is preserve', async () => {
     tree.overwrite(
       'tsconfig.json',

From 60392dd84e863bc09754a34efccca53a82d4173c Mon Sep 17 00:00:00 2001
From: Raashish Aggarwal <94279692+raashish1601@users.noreply.github.com>
Date: Fri, 27 Mar 2026 19:04:08 +0530
Subject: [PATCH 2/3] fix(@schematics/angular): keep existing build versions

---
 .../use-application-builder/migration.ts       | 12 ++++++------
 .../use-application-builder/migration_spec.ts  | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/packages/schematics/angular/migrations/use-application-builder/migration.ts b/packages/schematics/angular/migrations/use-application-builder/migration.ts
index 9a0040ad9f1d..ea7afb5beba8 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration.ts
@@ -15,11 +15,11 @@ import {
   externalSchematic,
 } from '@angular-devkit/schematics';
 import { dirname, join } from 'node:path/posix';
-import { getPackageJsonDependency } from '../../utility/dependencies';
 import {
   DependencyType,
   ExistingBehavior,
   addDependency,
+  getDependency,
   removeDependency,
 } from '../../utility/dependency';
 import { JSONFile } from '../../utility/json-file';
@@ -271,13 +271,13 @@ function updateProjects(tree: Tree, context: SchematicContext) {
       }
 
       // Add direct @angular/build dependencies and remove @angular-devkit/build-angular
-      const buildDependency =
-        getPackageJsonDependency(tree, '@angular-devkit/build-angular') ??
-        getPackageJsonDependency(tree, '@angular/build');
+      const buildAngularVersion =
+        getDependency(tree, '@angular-devkit/build-angular')?.version ??
+        latestVersions.DevkitBuildAngular;
       rules.push(
-        addDependency('@angular/build', buildDependency?.version ?? latestVersions.AngularBuild, {
+        addDependency('@angular/build', buildAngularVersion, {
           type: DependencyType.Dev,
-          existing: ExistingBehavior.Replace,
+          existing: ExistingBehavior.Skip,
         }),
         removeDependency('@angular-devkit/build-angular'),
       );
diff --git a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
index 70730d73de5e..72a29805c9e8 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
@@ -467,6 +467,24 @@ describe(`Migration to use the application builder`, () => {
     expect(devDependencies['@angular-devkit/build-angular']).toBeUndefined();
   });
 
+  it('should preserve an existing "@angular/build" version when migrating', async () => {
+    tree.overwrite(
+      '/package.json',
+      JSON.stringify({
+        devDependencies: {
+          '@angular-devkit/build-angular': '~18.2.20',
+          '@angular/build': '~18.2.10',
+        },
+      }),
+    );
+
+    const newTree = await schematicRunner.runSchematic(schematicName, {}, tree);
+
+    const { devDependencies } = JSON.parse(newTree.readContent('/package.json'));
+    expect(devDependencies['@angular/build']).toBe('~18.2.10');
+    expect(devDependencies['@angular-devkit/build-angular']).toBeUndefined();
+  });
+
   it('it should not add esModuleInterop and moduleResolution when module is preserve', async () => {
     tree.overwrite(
       'tsconfig.json',

From c82410d03d824d9a71adbbe962e11afd407b1618 Mon Sep 17 00:00:00 2001
From: Raashish Aggarwal <94279692+raashish1601@users.noreply.github.com>
Date: Sat, 28 Mar 2026 19:00:40 +0530
Subject: [PATCH 3/3] fix(@schematics/angular): use angular build fallback
 version

---
 .../migrations/use-application-builder/migration.ts      | 2 +-
 .../migrations/use-application-builder/migration_spec.ts | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/schematics/angular/migrations/use-application-builder/migration.ts b/packages/schematics/angular/migrations/use-application-builder/migration.ts
index ea7afb5beba8..9df1e7df0c44 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration.ts
@@ -273,7 +273,7 @@ function updateProjects(tree: Tree, context: SchematicContext) {
       // Add direct @angular/build dependencies and remove @angular-devkit/build-angular
       const buildAngularVersion =
         getDependency(tree, '@angular-devkit/build-angular')?.version ??
-        latestVersions.DevkitBuildAngular;
+        latestVersions.AngularBuild;
       rules.push(
         addDependency('@angular/build', buildAngularVersion, {
           type: DependencyType.Dev,
diff --git a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
index 72a29805c9e8..f5cc0002d534 100644
--- a/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
+++ b/packages/schematics/angular/migrations/use-application-builder/migration_spec.ts
@@ -9,6 +9,7 @@
 import { JsonObject } from '@angular-devkit/core';
 import { EmptyTree } from '@angular-devkit/schematics';
 import { SchematicTestRunner, UnitTestTree } from '@angular-devkit/schematics/testing';
+import { latestVersions } from '../../utility/latest-versions';
 import { Builders, ProjectType, WorkspaceSchema } from '../../utility/workspace-models';
 
 function createWorkSpaceConfig(tree: UnitTestTree) {
@@ -467,6 +468,14 @@ describe(`Migration to use the application builder`, () => {
     expect(devDependencies['@angular-devkit/build-angular']).toBeUndefined();
   });
 
+  it('should use the latest "@angular/build" version when no builder is installed', async () => {
+    const newTree = await schematicRunner.runSchematic(schematicName, {}, tree);
+
+    const { devDependencies } = JSON.parse(newTree.readContent('/package.json'));
+    expect(devDependencies['@angular/build']).toBe(latestVersions.AngularBuild);
+    expect(devDependencies['@angular-devkit/build-angular']).toBeUndefined();
+  });
+
   it('should preserve an existing "@angular/build" version when migrating', async () => {
     tree.overwrite(
       '/package.json',