From 745d777288a5ae0e79b4ecdf7b8483f242ba8e66 Mon Sep 17 00:00:00 2001
From: Alan Agius <alan.agius4@gmail.com>
Date: Fri, 22 Oct 2021 11:56:28 +0200
Subject: [PATCH] fix(@angular/cli): error when updating Angular packages
 across multi-major migrations

With this change we show an error message when users try to update `@angular/` and `@nguniversal/` packages across multiple major versions.

(cherry picked from commit d60d374389043174050c9f86a1c7aea4bab2cf1c)
---
 packages/angular/cli/commands/update-impl.ts  | 31 ++++++++++++++++++-
 .../tests/update/update-multiple-versions.ts  | 20 ++++++++++++
 2 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 tests/legacy-cli/e2e/tests/update/update-multiple-versions.ts

diff --git a/packages/angular/cli/commands/update-impl.ts b/packages/angular/cli/commands/update-impl.ts
index 6d972746a9ee..7002d4f8c8a4 100644
--- a/packages/angular/cli/commands/update-impl.ts
+++ b/packages/angular/cli/commands/update-impl.ts
@@ -629,11 +629,40 @@ export class UpdateCommand extends Command<UpdateCommandSchema> {
         return 1;
       }
 
-      if (manifest.version === node.package.version) {
+      if (manifest.version === node.package?.version) {
         this.logger.info(`Package '${packageName}' is already up to date.`);
         continue;
       }
 
+      if (node.package && /^@(?:angular|nguniversal)\//.test(node.package.name)) {
+        const { name, version } = node.package;
+        const toBeInstalledMajorVersion = +manifest.version.split('.')[0];
+        const currentMajorVersion = +version.split('.')[0];
+
+        if (toBeInstalledMajorVersion - currentMajorVersion > 1) {
+          // Only allow updating a single version at a time.
+          if (currentMajorVersion < 6) {
+            // Before version 6, the major versions were not always sequential.
+            // Example @angular/core skipped version 3, @angular/cli skipped versions 2-5.
+            this.logger.error(
+              `Updating multiple major versions of '${name}' at once is not supported. Please migrate each major version individually.\n` +
+                `For more information about the update process, see https://update.angular.io/.`,
+            );
+          } else {
+            const nextMajorVersionFromCurrent = currentMajorVersion + 1;
+
+            this.logger.error(
+              `Updating multiple major versions of '${name}' at once is not supported. Please migrate each major version individually.\n` +
+                `Run 'ng update ${name}@${nextMajorVersionFromCurrent}' in your workspace directory ` +
+                `to update to latest '${nextMajorVersionFromCurrent}.x' version of '${name}'.\n\n` +
+                `For more information about the update process, see https://update.angular.io/?v=${currentMajorVersion}.0-${nextMajorVersionFromCurrent}.0`,
+            );
+          }
+
+          return 1;
+        }
+      }
+
       packagesToUpdate.push(requestIdentifier.toString());
     }
 
diff --git a/tests/legacy-cli/e2e/tests/update/update-multiple-versions.ts b/tests/legacy-cli/e2e/tests/update/update-multiple-versions.ts
new file mode 100644
index 000000000000..1a5bbb2c4d4f
--- /dev/null
+++ b/tests/legacy-cli/e2e/tests/update/update-multiple-versions.ts
@@ -0,0 +1,20 @@
+import { createProjectFromAsset } from '../../utils/assets';
+import { ng } from '../../utils/process';
+import { expectToFail } from '../../utils/utils';
+
+export default async function () {
+  await createProjectFromAsset('7.0-project');
+
+  const extraArgs = ['--force'];
+  const { message } = await expectToFail(() =>
+    ng('update', '@angular/core', ...extraArgs),
+  );
+  if (
+    !message.includes(`Updating multiple major versions of '@angular/core' at once is not supported`)
+  ) {
+    console.error(message);
+    throw new Error(
+      `Expected error message to include "Updating multiple major versions of '@angular/core' at once is not supported" but didn't.`,
+    );
+  }
+}