Watch mode (ng test, ng serve) stalls after "Watch mode enabled" when preserveSymlinks: true — chokidar scans entire workspace incl. node_modules (regression in 22.2.0) #34162

Command

• test
• 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

22.1.8

Description

(AI generated)

After updating @angular/build / @angular/cli from 22.1.8 to 22.2.0, ng test in watch mode (@angular/build:unit-test, Vitest runner) no longer starts running tests after the initial build when the build target has "preserveSymlinks": true. The output stops at:

Application bundle generation complete. [52.899 seconds]

Watch mode enabled. Watching for file changes...

With NG_TEST_LOG=1, VitestExecutor never logs Executing test run — the first build result is not handed to the executor. We stopped the process after more than 4 minutes of waiting. ng test --watch=false is unaffected (the full suite finishes in ~3 min including the build).

Setting "preserveSymlinks": false in the test build configuration makes Vitest start ~2 s after the build completes. Downgrading Vitest (5.0.1 → 4.1.11) makes no difference, so it is not Vitest-related.

Cause (from reading @angular/build 22.2.0 sources):

In src/builders/application/build-action.js, watch mode now calls setupWatcher() from src/utils/watcher.js before emitting the first build result:

1. createWatcher() uses chokidar instead of @parcel/watcher whenever followSymlinks (= preserveSymlinks) is true.
2. createChokidarWatcher() calls chokidar.watch(rootDir, …) on the entire workspace root (cwd: workspaceRoot), regardless of NG_BUILD_WATCH_ROOT.
3. The **/node_modules/** ignore pattern is only added when shouldWatchRoot && !preserveSymlinks, so with preserveSymlinks: true chokidar also walks all of node_modules (≈106 000 files in our workspace).
4. It then does await once(watcher, 'ready') (added in fix(@angular/build): ensure chokidar watcher is ready before returning #34122), i.e. it blocks until that full initial scan has completed — with followSymlinks: true on Windows.

In 22.1.8, build-action.js used tools/esbuild/watcher.js and only watched the files/directories from result.watchFiles (plus the project root only if NG_BUILD_WATCH_ROOT was set), with no wait for an initial scan, so startup was instant.

preserveSymlinks: true is a common setting for workspaces that npm link local libraries, so this effectively makes watch mode unusable for them.

Since ng serve and ng build --watch go through the same runEsBuildBuildAction / setupWatcher path, they are affected as well, see comment below.

Possible fixes:

• Keep watching only watchFiles (and the root only with NG_BUILD_WATCH_ROOT), as in 22.1.8, for the chokidar path; or
• ignore node_modules under the workspace root in the chokidar path as well — explicitly added watch files outside the root (e.g. npm link targets) would still be watched; or
• don't block the first build result on chokidar's ready when the initial scan is large.

Minimal Reproduction

Verified by me (human): https://github.com/reifi/angular-preserve-symlinks-watch-repro

Reproducible with a freshly generated project:

1. npx @angular/cli@22.2.0 new repro --defaults --test-runner=vitest
2. In angular.json, add "preserveSymlinks": true to projects.repro.architect.build.options.
3. Run ng test (watch mode; ng test --watch in a non-TTY shell).
4. Observe: output stops after "Watch mode enabled. Watching for file changes..." for about 2 minutes before Vitest starts.

Measured on Windows 11, fresh project (≈18 000 files in node_modules), time from "Watch mode enabled" to the Vitest test summary:

The delay scales with the number of files under the workspace root. In a large application workspace (≈106 000 files in node_modules) tests had still not started after more than 4 minutes, when we stopped the process. ng test --watch=false is not affected.

Exception or Error

No error — the process hangs silently after:

Watch mode enabled. Watching for file changes...

Your Environment

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


Angular CLI       : 22.2.0
Angular           : 22.2.0
Node.js           : 26.8.2
Package Manager   : npm 11.19.1
Operating System  : win32 x64

┌─────────────────────────────────┬───────────────────┬───────────────────┐
│ Package                         │ Installed Version │ Requested Version │
├─────────────────────────────────┼───────────────────┼───────────────────┤
│ @angular/build                  │ 22.2.0            │ ^22.2.0           │
│ @angular/cdk                    │ 22.2.0            │ ^22.2.0           │
│ @angular/cli                    │ 22.2.0            │ ^22.2.0           │
│ @angular/common                 │ 22.2.0            │ ^22.2.0           │
│ @angular/compiler               │ 22.2.0            │ ^22.2.0           │
│ @angular/compiler-cli           │ 22.2.0            │ ^22.2.0           │
│ @angular/core                   │ 22.2.0            │ ^22.2.0           │
│ @angular/forms                  │ 22.2.0            │ ^22.2.0           │
│ @angular/google-maps            │ 22.2.0            │ ^22.2.0           │
│ @angular/localize               │ 22.2.0            │ ^22.2.0           │
│ @angular/material               │ 22.2.0            │ ^22.2.0           │
│ @angular/material-luxon-adapter │ 22.2.0            │ ^22.2.0           │
│ @angular/platform-browser       │ 22.2.0            │ ^22.2.0           │
│ @angular/router                 │ 22.2.0            │ ^22.2.0           │
│ @angular/upgrade                │ 22.2.0            │ ^22.2.0           │
│ rxjs                            │ 7.8.2             │ ^7.8.2            │
│ typescript                      │ 6.0.3             │ ^6.0.3            │
│ vitest                          │ 5.0.1             │ ^5.0.1            │
│ zone.js                         │ 0.16.3            │ ^0.16.3           │
└─────────────────────────────────┴───────────────────┴───────────────────┘

Anything else relevant?

Workaround: override "preserveSymlinks": false in the build configuration referenced by the unit-test buildTarget, e.g.

"configurations": {
  "test": {
    "preserveSymlinks": false,
    …
  }
}

The unit-test builder reads preserveSymlinks from the build target options (unit-test/options.js), so this only affects tests; ng serve / ng build keep preserveSymlinks: true for npm link.