Slow build: loadNgStructureAsync takes 73 secs

[vivainio]

🐞 Bug report

Command (mark with an x)

• new
• build
• serve
• test
• e2e
• generate
• add
• update
• lint
• xi18n
• run
• config
• help
• version
• doc

Is this a regression?

Yes, Angular 8 was not blocked here.

Description

• Enable benchmarking in:

....\node_modules/@ngtools\webpack\src\benchmark.js

(const benchmark = true)

Observe that there is a clear slow phase in the build:

NgccProcessor.processModule.ngcc.process+webpack-sources: 3.247ms
NgccProcessor.processModule.ngcc.process+yargs: 3.237ms
NgccProcessor.processModule.ngcc.process+source-map: 2.713ms
AngularCompilerPlugin._createOrUpdateProgram.ng.createProgram: 13105.799ms
30% building 13/13 modules 0 activeAngularCompilerPlugin._createOrUpdateProgram.ng.loadNgStructureAsync: 73171.067ms   <=== BOOOM
AngularCompilerPlugin._make.resolveEntryModuleFromMain: 21.720ms
AngularCompilerPlugin._listLazyRoutesFromProgram.listLazyRoutes: 77.186ms
AngularCompilerPlugin._emit.ng.getNgStructuralDiagnostics: 0.024ms

🔬 Minimal Reproduction

Not currently. This is our proprietary product.

🌍 Your Environment

Angular CLI: 9.0.7
Node: 10.16.0
OS: win32 x64

Angular: 9.0.7
... animations, cli, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... platform-server, router
Ivy Workspace: Yes

Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.901.7
@angular-devkit/build-angular      0.901.7
@angular-devkit/build-ng-packagr   0.901.7
@angular-devkit/build-optimizer    0.901.7
@angular-devkit/build-webpack      0.901.7
@angular-devkit/core               9.0.7
@angular-devkit/schematics         9.0.7
@angular/cdk                       9.2.4
@angular/material                  9.2.4
@ngtools/webpack                   9.1.7
@schematics/angular                9.0.7
@schematics/update                 0.900.7
ng-packagr                         9.0.0
rxjs                               6.5.4
typescript                         3.7.5
webpack                            4.42.0

Anything else relevant?

I downgraded to 9.0.7 as hinted by angular/angular#36272. Build time with 9.1.9 was even worse.

[alan-agius4]

What were the timings for loadNgStructureAsync in Angular 8?

[vivainio]

loadNgStructureAsyng is actually not there in Angular 8 output.

Here's the beginning of the profile from Angular 8.3.0:

AngularCompilerPlugin._setupOptions: 661.030ms
AngularCompilerPlugin._createOrUpdateProgram.ts.createProgram: 11604.765ms
AngularCompilerPlugin._make.resolveEntryModuleFromMain: 8.484ms
AngularCompilerPlugin._listLazyRoutesFromProgram.createProgram: 7.179ms
AngularCompilerPlugin._listLazyRoutesFromProgram.listLazyRoutes: 3217.039ms
AngularCompilerPlugin._emit.ts.getOptionsDiagnostics: 0.185ms
AngularCompilerPlugin._emit.ts.gatherDiagnostics.ts.getSyntacticDiagnostics: 1.966ms
AngularCompilerPlugin._emit.ts.gatherDiagnostics.ts.getSemanticDiagnostics: 11583.725ms
AngularCompilerPlugin._emit: 22501.209ms
AngularCompilerPlugin._update._emit: 22502.043ms
AngularCompilerPlugin._update: 38016.477ms
AngularCompilerPlugin._make: 38017.190ms

after _make, it stops "hanging" and starts quickly compiling ts files.

[vivainio]

For completeness, here's new snippet from Angular 9.0.7, showing getSemanticDiagnostics etc, and how loadNgStructruceAsyng looks like entirely new slow phase introduced in Angular 9.

AngularCompilerPlugin._createOrUpdateProgram.ng.createProgram: 13101.918ms
AngularCompilerPlugin._createOrUpdateProgram.ng.loadNgStructureAsync: 73200.319ms
AngularCompilerPlugin._make.resolveEntryModuleFromMain: 24.710ms
AngularCompilerPlugin._listLazyRoutesFromProgram.listLazyRoutes: 74.687ms
AngularCompilerPlugin._emit.ng.getNgStructuralDiagnostics: 0.167ms
AngularCompilerPlugin._emit.ng.getTsOptionDiagnostics: 0.286ms
AngularCompilerPlugin._emit.ng.getNgOptionDiagnostics: 0.057ms
AngularCompilerPlugin._emit.ng.gatherDiagnostics.ng.getTsSyntacticDiagnostics: 2.743ms
AngularCompilerPlugin._emit.ng.gatherDiagnostics.ng.getTsSemanticDiagnostics: 13985.054ms
AngularCompilerPlugin._emit.ng.gatherDiagnostics.ng.getNgSemanticDiagnostics: 3502.293ms

[vivainio]

Possibly related (based on git logs):

angular/angular#34792

cc @alxhub

[alan-agius4]

Hi @vivainio,

The main difference between version 8 and version 9. Is that AOT is turned on by default. Hence, that is why loadNgStructureAsync is not listed in the above version 8 logs, because with version 8 you are running a JIT build.

Indeed loadNgStructureAsync, is taking a lot of time in your case. However, to investigate this we'll be needing a reproduction. Can you please share a reproduction, even privately? thanks.

[vivainio]

@alan-agius4 I'll see if I can deliver a private repro. Where / how should I deliver that securely?

[alan-agius4]

You can share that via email.

[elvisbegovic]

Hi,
This should be related to angular/angular#35906 or this earlier angular/angular#34867 🤔 ?

[alan-agius4]

@elvisbegovic, the shared issues are related to incremental recompilations. The above looks like a cold build.

[vivainio]

Yes, this is a cold build.

At this time, I'm working around this problem by disabling aot compiler, i.e. passing "--aot false" to "ng build". Indeed there is no loadNgStructureAsync freeze anymore, and app seems to still work :).