"Sealing" phase is stuck on

[alexandis]

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

13.2.0

Description

Generating browser applicaiton bundles (phase: sealing) - never ends.

Minimal Reproduction

I've upgraded my solution from Angular 13.2.0 to 15.0.1...
I've successfully build all the projects both in Production and Development configurations. But I cannot get through "sealing" phase. I don't understand whose exactly this problem is and how to debug what is it stuck on?

Exception or Error

No response

Your Environment

Package Version
---------------------------------------------------------
@angular-devkit/architect 0.1502.0
@angular-devkit/build-angular 15.2.0
@angular-devkit/core 15.0.5
@angular-devkit/schematics 15.0.5
@schematics/angular 15.2.0
ng-packagr 15.2.2
rxjs 7.8.0
typescript 4.8.4

Anything else relevant?

No response

[alan-agius4]

You could generate a CPU profile.

See: https://github.com/angular/angular-cli/blob/main/docs/DEVELOPER.md#cpu-profiling

[alexandis]

UPDATE: after about 1.5 hour (!) of just stucking, it finally gave me the error:

[alexandis]

Moving on. It does not look like CPU is working at all during "sealing":

[alexandis]

I've tried to debug "ng serve" and here's what is happening while "stuck" on "sealing" phase. I pressed "Pause" in debugger and there are numerous parsing errors inside this method which seem to silently "swallowed":

1. If it it something of this sort - i.e. I need to include all such CSS into angular.json "styles" or "assets" section - i've tried it, but still getting the same error; 2) I suppose the sealing phase shouldn't stuck for 1.5 hour and the error message should be given to a user immediately. Or am I missing something?

Everything worked "as is" before upgrade.

[alan-agius4]

@alexandis, would please provide one of these error message in a gist?

[alexandis]

@alexandis, would please provide one of these error message in a gist?
Sure. Gist. Here are also configurations which might come handy.

[alan-agius4]

Thanks @alexandis, I did manage to get to the bottom of why the build is getting stuck and I have a PR to fix it. For the time being as a workaround you can run build/serve with the --verbose command line argument.

Now, to the error itself, I don't know what's the root problem as I don't have context of how this stylesheet is being used in the application. How is this CSS being used? Are you importing the CSS file in your JS? In that case, you are problem encountered one of the breaking changes in version 14.

We now issue a build time error since importing a CSS file as an ECMA module is non standard Webpack specific feature, which is not supported by the Angular CLI. This feature was never truly supported by the Angular CLI, but has as such for visibility.

See https://github.com/angular/angular-cli/releases/tag/14.0.0 for the full list of breaking changes in v14.

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By the way, well done into getting to the bottom of why the build is stuck.