Please backport PR #33285 to the `21.x` branch.

[jkoervers]

Command

add

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

PR #33285 fixes a bug that is currently affecting our project on Angular v21. Since the fix was merged into main (targeted for v22), projects staying on Angular v21 still experience this bug. I will support Angular v21 for years in our private library, so running ng add twice to make the schematic run is very unfortunate.

• Original PR: fix(@angular/cli): fallback to local package.json for schematic detection on first run #33285

Impact

This fix is necessary for teams using Angular v21 who need to support v21 alongside of v22. Backporting this to a 21.x patch release would resolve the issue for active v21 builds.

Minimal Reproduction

Please see issue #33060 for the description.

Exception or Error

Your Environment

Angular CLI       : 21.2.6
Angular           : 21.2.6
Node.js           : 22.13.0
Package Manager   : npm 10.9.2
Operating System  : win32 x64

┌───────────────────────────────────┬───────────────────┬───────────────────┐
│ Package                           │ Installed Version │ Requested Version │
├───────────────────────────────────┼───────────────────┼───────────────────┤
│ @angular-devkit/build-angular     │ 21.2.6            │ ^21.1.2           │
│ @angular/animations               │ 21.2.6            │ ^21.1.2           │
│ @angular/build                    │ 21.2.6            │ ^21.1.2           │
│ @angular/cdk                      │ 21.2.4            │ ^21.1.2           │
│ @angular/cli                      │ 21.2.6            │ ^21.1.2           │
│ @angular/common                   │ 21.2.6            │ ^21.1.2           │
│ @angular/compiler                 │ 21.2.6            │ ^21.1.2           │
│ @angular/compiler-cli             │ 21.2.6            │ ^21.1.2           │
│ @angular/core                     │ 21.2.6            │ ^21.1.2           │
│ @angular/forms                    │ 21.2.6            │ ^21.1.2           │
│ @angular/platform-browser         │ 21.2.6            │ ^21.1.2           │
│ @angular/platform-browser-dynamic │ 21.2.6            │ ^21.1.2           │
│ @angular/router                   │ 21.2.6            │ ^21.1.2           │
│ ng-packagr                        │ 21.2.2            │ ^21.2.2           │
│ rxjs                              │ 7.8.2             │ ~7.8.2            │
│ typescript                        │ 5.9.3             │ ~5.9.3            │
│ vitest                            │ 4.1.7             │ ^4.1.7            │
│ zone.js                           │ 0.15.1            │ ~0.15.0           │
└───────────────────────────────────┴───────────────────┴───────────────────┘

Anything else relevant?

No response

[alan-agius4]

Version 21 is currently in Long-Term Support (LTS) and receives only security-related updates.