Ng serve does not rebuild after changes in library referenced in tsconfig paths

[antoine-carruana]

Command

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

18.2.12

Description

Hi,

I have recently migrated from an angular 18 project to the 20 version.

I have a custom library and an app. To gain time and avoid multiple builds and having to build both the lib and the app I have referenced the lib (which is a dependency in the app) with paths to the local project in the tsconfig of the app.

When doing this, I referenced my public_api.ts and doing so, I don't have to build watch the library, any changes made in the library is automatically picked up by the serve of the app and a rebuild is done as if it was a change in the app.

Doing the same thing in angular 20 does not work, I have made some researchand read somewhere that the paths cannot react if it's not in the same workspace.

Should we not have a property somewhere to activate this ?

I have recreated a small lib and small app in angular 18 it works, in angular 20 I cannot manage to make it happen.

Thank you in advance

Regards

Minimal Reproduction

Create a lib in a folder
Create an app in another folder
Install the lib as a dependency in the app
In the tsconfig add a path property and reference the multiple public_api.ts of your lib

Exception or Error

Your Environment

Angular CLI: 18.2.12
Node: 22.17.0
Package Manager: npm 11.6.0
OS: win32 x64

Angular: 18.2.12
... build, cli, common, compiler, compiler-cli, core, forms
... platform-browser, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1802.12
@angular-devkit/build-angular   18.2.12
@angular-devkit/core            18.2.12
@angular-devkit/schematics      18.2.12
@schematics/angular             18.2.12
ng-packagr                      18.2.1
rxjs                            7.8.1
typescript                      5.5.2
zone.js                         0.14.10

Anything else relevant?

No response

[alan-agius4]

This is working as intended. Please see: #27176 (comment). For library development, install of install the dependency, you could link it instead if the library is in another repository.