Esbuild builder doesn't copy assets in watch mode

[PooSham]

Command

build

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

browser builder (webpack based)

Description

When running ng build --watch with either the build-esbuild or application builder, there is first a build step where everything is copied to the destination folder, including assets, but if a change is made to an asset after the initial bundle, then nothing happens. I'd expect the assets defined in the builders' "assets" option to also be updated during watch mode.

When I try the same in the webpack based "browser" builder, then everything is copied.

Minimal Reproduction

• In angular.json, put the following inside "architect":

"build": {
    "builder": "@angular-devkit/build-angular:application",
    "options": {
        "assets": ["src/assets"],
        "index": "src/index.html",
        "browser": "src/main.ts",
        "outputPath": "dist",
        "tsConfig": "tsconfig.app.json"
    }
}

• Make sure you have an index.html, main.ts and tsconfig.app.json.
• Put some text file inside of src/assets.
• Run ng build --watch.
• Make a change to the text file inside the assets folder
• Notice that the file hasn't been updated inside the dist folder

Exception or Error

No response

Your Environment

Angular CLI: 18.2.1
Node: 20.12.0
Package Manager: npm 10.5.0
OS: win32 x64

Angular: 18.2.1
... animations, cdk, cli, common, core, elements, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1802.1
@angular-devkit/build-angular   18.2.1
@angular-devkit/core            18.2.1
@angular-devkit/schematics      18.2.1
@schematics/angular             18.2.1
rxjs                            7.8.1
typescript                      5.5.4

Anything else relevant?

I have tried to dive into the Angular CLI source code, and I found that the watcher is given which files to watch here. I think the result comes from here, but it's a bit abstracted away and I can't easily find the source.