`ng update` does not execute migrations for GitHub Packages packages although `--migrate-only` works and migration exists in build

[jkoervers]

Command

update

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

not working in v19, v20 and v21, cannot confirm for other versions

Description

I maintain an Angular library that provides migrations via ng update.

The library is published through two different registries:

• GitHub Packages
• Verdaccio

The package contains:

{
  "schematics": "./schematics/collection.json",
  "ng-update": {
    "migrations": "./schematics/migration.json"
  }
}

and the migration is registered in:

{
  "schematics": {
    "migration-rfc-001": {
      "version": "21.2.0",
      "factory": "./migrations/rfc-001-utilities-modular-import/index#addUtilitiesModularImport"
    }
  }
}

The migration can be executed successfully when:

ng generate @company/library-name:migration-rfc-001

and also when using:

ng update @company/library-name \
  --migrate-only \
  --from 21.1.0 \
  --to 21.2.0-next21.1

However, when performing a normal update from GitHub Packages:

ng update @company/library-name@21.2.0-next21.1

Angular updates the package but never executes the migration.

The exact same migration works correctly when the package is published to Verdaccio.

---

Expected behavior

Running:

ng update @company/library-name@21.2.0-next21.1

should:

1. Update the dependency.
2. Discover the migration.
3. Execute the migration automatically.

Expected output similar to:

** Executing migrations of package '@company/library-name' **

---

Actual behavior

Angular updates package.json and reinstalls packages but never executes migrations.

Output:

Updating package.json with dependency @company/library-name @ "21.2.0-next21.1" (was "21.1.0")...
UPDATE package.json

✔ Cleaning node modules directory
✔ Installing packages.

No migration execution follows.

---

Reproduction

Initial version

"@company/library-name": "21.1.0"

Target version

"@company/library-name": "21.2.0-next21.1"

Command

ng update @company/library-name@21.2.0-next21.1 --verbose

Result

Package is updated.

Migration is not executed.

---

Evidence that the migration itself is valid

The migration executes successfully when invoked explicitly:

ng update @company/library-name \
  --migrate-only \
  --from 21.1.0 \
  --to 21.2.0-next21.1 \
  --verbose

Output:

** Executing migrations of package '@company/library-name' **

❯ Automatically does xyz during 21.2.0-next21.1 upgrade.

UPDATE src/styles.scss
Migration completed (1 file modified).

This demonstrates that Angular can:

• locate the package
• read ng-update
• load migration.json
• execute the migration implementation

---

Package verification

The published package contains:

schematics/collection.json
schematics/migration.json
schematics/migrations/rfc-001-utilities-modular-import/index.js

The installed package contains:

{
  "schematics": "./schematics/collection.json",
  "ng-update": {
    "migrations": "./schematics/migration.json"
  }
}

Tarballs from both registries were compared and contain the migration files.

---

Interesting registry difference

When inspecting registry metadata:

GitHub Packages

npm view @company/library-name@21.2.0-next21.1 --json

The returned metadata does not contain:

"schematics"

or

"ng-update"

even though both entries exist inside the package's package.json.

Verdaccio

npm view @company/library-name@21.2.0-next21.1 --json --registry=http://localhost:4873

returns:

{
  "schematics": "./schematics/collection.json",
  "ng-update": {
    "migrations": "./schematics/migration.json"
  }
}

For packages published via Verdaccio, automatic migration execution works correctly.

---

Question

Does Angular CLI rely on registry metadata returned by the package registry when determining whether migrations should run during ng update?

If so, could a registry that does not expose the ng-update and schematics fields (while still shipping them inside the tarball) cause Angular CLI to skip migration execution during a normal update, even though:

ng update --migrate-only

works correctly?

Minimal Reproduction

See above.

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