File replacements are ignored for web workers

Start with the linked StackBlitz reproduction and its angular.json, then compare how file replacements are applied to the component and web worker for both build and serve. Done means env.prod.ts is used by the worker as well as the component under the configured replacement, using either builder.

Command

build, serve

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

v18

Description

Hi, we recently updated to angular v19. During that we also migrated the builder to the recommended @angular/build builder, but in my tests the error also occured for the old devkit builder. After the update, we noticed that file replacements are ignored for web workers, see minimal reproduction. Before our upgrade, this was working without problems. I'm happy about any help :)

Minimal Reproduction

StackBlitz: https://stackblitz.com/edit/4gqtqodb

After everything was built, you will see in the console:

Component: production
Worker: development

However, as defined in the angular.json, the file env.ts should be replaced by env.prod.ts, which is done correctly in the component.

Exception or Error

Your Environment

_                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI: 19.0.7
Node: 18.20.3
Package Manager: npm 10.2.3
OS: linux x64

Angular: 19.0.6
... animations, common, compiler, compiler-cli, core, forms
... platform-browser

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.1900.7
@angular-devkit/core         19.0.7
@angular-devkit/schematics   19.0.7
@angular/build               19.0.7
@angular/cdk                 19.0.5
@angular/cli                 19.0.7
@angular/material            19.0.5
@schematics/angular          19.0.7
rxjs                         7.8.1
typescript                   5.6.3
zone.js                      0.15.0

Anything else relevant?

Seems to happen for both build and serve, local and on stackblitz and for both the devkit and the new builder.