HMR updates triggers full page reload when SSR is enabled

[alan-agius4]

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

In version 19.1.0-rc.0, updating a component's stylesheet did not trigger a full page reload, whereas updates to component templates always did.

Description

When SSR is enabled in ng serve, HMR updates are always followed by a full page reload.

Minimal Reproduction

$ ng new --ssr --server-routing
$ ng s

Next, update the template or stylesheet of a component. In the console, you will see both Component update sent to client(s). and Page reload sent to client(s). being displayed.

Exception or Error

When SSR is enabled, hot module replacement (HMR) is executed but is immediately followed by a full page reload.

Your Environment

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

Angular CLI: 19.1.1
Node: 20.17.0
Package Manager: yarn 1.22.22
OS: linux x64

Angular: 19.1.1
... animations, cli, common, compiler, compiler-cli, core, forms
... platform-browser-dynamic, platform-server, router, ssr

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1901.1
@angular-devkit/build-angular   19.1.1
@angular-devkit/core            19.1.1
@angular-devkit/schematics      19.1.1
@angular/platform-browser       19.0.0
@schematics/angular             19.1.1
rxjs                            7.8.1
typescript                      5.7.3
zone.js                         0.15.0

Anything else relevant?

No response