Description

In bundled dev mode (experimental.bundledDev), when a file change breaks the build (for example an import path that cannot be resolved), the error is only shown in the browser overlay. The terminal prints nothing.

Expected behavior is the same as normal dev mode: every failed build prints the error in the terminal, and after the file is fixed the terminal shows the recovery (hmr update / page reload).

The cause is that the two dev engine callbacks handle errors differently:

• The onOutput error branch logs ✘ Build error to the terminal and sends the overlay.
• The onHmrUpdates error branch only sends the overlay.

With the default rebuild strategy, a file change only generates HMR updates, so a failed rebuild goes through onHmrUpdates and the terminal stays silent.

This PR adds the same ✘ Build error logging to the onHmrUpdates error branch.

Before:

(nothing is printed on a failed HMR rebuild)

After:

✘ Build error: Build failed with 1 error:

[UNRESOLVED_IMPORT] Could not resolve './src/components/HelloWorld.vue' in src/App.vue
   ╭─[ src/App.vue:2:24 ]
   │
 2 │ import HelloWorld from "./src/components/HelloWorld.vue";
   │                        ────────────────┬────────────────
   │                                        ╰────────────────── Module not found.
───╯

Also added a serverLogs assertion to the existing handle generate hmr patch error playground test. The assertion fails without this fix and passes with it.

closes rolldown/rolldown#10136