Angular 9/Ivy + i18n: Empty main.js.map when built in watch mode

[mkemmerling]

🐞 bug report

Affected Package

The issue is caused by Ivy.

Is this a regression?

Yes, the previous version in which this bug was not present was: Angular 8

Description

In Angular 9 when building a localized bundle in watch mode with, e.g., ng build --configuration=de --watch the created main.js.map SourceMap is just an empty object.

Not sure if this is a bug or just a missing feature, but I couldn't find any documentation about it.

When Ivy is disabled in tsconfig.json the SourceMap is built as expected. The problem also doesn't occur with ng serve.

🔬 Minimal Reproduction

See https://github.com/mkemmerling/angular9_i18n_build_watch

This is just a minimal 'repro-app' with i18n configuration as described in the Angular docs.

To reproduce the error run ng build --configuration=de --watch and inspect the empty main.js.map SourceMap in dist/repro-app/de.

🌍 Your Environment

Angular Version:

Angular CLI: 9.0.1
Node: 13.8.0
OS: darwin x64

Angular: 9.0.0
... animations, common, compiler, compiler-cli, core, forms
... language-service, localize, platform-browser
... platform-browser-dynamic, router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.900.1
@angular-devkit/build-angular     0.900.1
@angular-devkit/build-optimizer   0.900.1
@angular-devkit/build-webpack     0.900.1
@angular-devkit/core              9.0.1
@angular-devkit/schematics        9.0.1
@angular/cli                      9.0.1
@ngtools/webpack                  9.0.1
@schematics/angular               9.0.1
@schematics/update                0.900.1
rxjs                              6.5.4
typescript                        3.7.5
webpack                           4.41.2

[alan-agius4]

Thanks for reporting this issue. This issue is now obsolete due to changes in the recent releases. Please update to the most recent Angular CLI version.

If the problem persists after upgrading, please open a new issue, provide a simple repository reproducing the problem, and describe the difference between the expected and current behavior.

[mkemmerling]

I can confirm that the problem is gone in Angular 9.1.7. Thanks for fixing!

[angular-automatic-lock-bot[bot]]

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