Vitest: resolved.coverage.exclude is not iterable in v20.1.0-next.1

[cexbrayat]

Command

test

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

20.1.0-next.0

Description

Running ng test with the vitest runner in v20.1.0-next.1 throws resolved.coverage.exclude is not iterable even without code coverage.

Minimal Reproduction

Generate a new app:

npx @angular/cli@20.1.0-next.1 new vitest-coverage --no-routing --defaults
cd vitest-coverage
npm install vitest jsdom --save-dev

Use the unit-test builder:

"test": {
  "builder": "@angular/build:unit-test",
  "options": {
    "tsConfig": "tsconfig.spec.json",
    "buildTarget": "::development",
    "runner": "vitest"
  }
}

Run ng test

Exception or Error

NOTE: The "unit-test" builder is currently EXPERIMENTAL and not ready for production use.
Initial chunk files  | Names             |  Raw size
chunk-46DE7USU.js    | -                 |   1.96 MB | 
init-testbed.js      | init-testbed      | 236.22 kB | 
polyfills.js         | polyfills         | 156.69 kB | 
spec-app-app.spec.js | spec-app-app.spec |  47.18 kB | 
styles.css           | styles            |  56 bytes | 

                     | Initial total     |   2.40 MB

Application bundle generation complete. [2.017 seconds]

Watch mode enabled. Watching for file changes...
An unhandled exception occurred: resolved.coverage.exclude is not iterable
See "/private/var/folders/fl/sx8_jbfd1gg3gg04jb0lr_n00000gn/T/ng-bvwmWs/angular-errors.log" for further details.

Your Environment

Angular CLI: 20.1.0-next.1
Node: 22.14.0
Package Manager: npm 10.9.0
OS: darwin arm64

Angular: 20.1.0-next.1
... build, cli, common, compiler, compiler-cli, core, forms
... platform-browser, router

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.2001.0-next.1
@angular-devkit/core         20.1.0-next.1
@angular-devkit/schematics   20.1.0-next.1
@schematics/angular          20.1.0-next.1
rxjs                         7.8.2
typescript                   5.8.3
zone.js                      0.15.1

Anything else relevant?

Reverting to next.0 solves the issue