Tests fail with `ɵmod` and `__ngAsyncComponentMetadataFn__` errors after migrating Karma builder to @angular/build:karma

[niwolf]

Command

test

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

with @angular-devkit/build-angular:karma

Description

Our project is a large enterprise application.
After migrating the test builder from @angular-devkit/build-angular:karma to esbuild-based @angular/build:karma, a significant number of our tests fail. The tests were all passing with the previous Webpack-based builder.

The primary errors are starting with TypeError: Cannot read properties of undefined (reading 'ɵmod') and are followed by TypeError: Cannot read properties of undefined (reading '__ngAsyncComponentMetadataFn__') which seems to be caused by stricter module and dependency resolution in the new builder.

This issue documents the patterns that were tolerated by the Webpack builder, but cause the esbuild builder to fail, making the migration very difficult for large-scale applications.

The production build of our app itself with ESBuild is working as expected with no issues after migration.

Minimal Reproduction

Have not been able to reproduce it in another repository

Exception or Error

1) Chrome Headless 138.0.0.0 (Mac OS 10.15.7) Component should do something FAILED
        TypeError: Cannot read properties of undefined (reading 'ɵmod')
            at getNgModuleDef (node_modules/@angular/core/fesm2022/core.mjs:1608:23)
            at isNgModule (node_modules/@angular/core/fesm2022/core.mjs:16500:12)
            at DepsTracker.computeNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16682:13)
            at DepsTracker.getNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16637:24)
            at DepsTracker.computeNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16657:36)
            at DepsTracker.getNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16637:24)
            at DepsTracker.computeNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16657:36)
            at DepsTracker.getNgModuleScope (node_modules/@angular/core/fesm2022/core.mjs:16637:24)
            at transitiveScopesFor (node_modules/@angular/core/fesm2022/core.mjs:33185:33)

2) TypeError: Cannot read properties of undefined (reading '__ngAsyncComponentMetadataFn__')
            at getAsyncClassMetadataFn (node_modules/@angular/core/fesm2022/core.mjs:20777:10)
            at TestBedCompiler.maybeRegisterComponentWithAsyncMetadata (node_modules/@angular/core/fesm2022/testing.mjs:1235:29)
            at TestBedCompiler.queueType (node_modules/@angular/core/fesm2022/testing.mjs:1243:10)
            at TestBedCompiler.queueTypeArray (node_modules/@angular/core/fesm2022/testing.mjs:1224:14)
            at queueTypesFromModulesArrayRecur (node_modules/@angular/core/fesm2022/testing.mjs:1305:16)
            at queueTypesFromModulesArrayRecur (node_modules/@angular/core/fesm2022/testing.mjs:1306:11)
            at queueTypesFromModulesArrayRecur (node_modules/@angular/core/fesm2022/testing.mjs:1306:11)
            at TestBedCompiler.queueTypesFromModulesArray (node_modules/@angular/core/fesm2022/testing.mjs:1332:5)
            at TestBedCompiler.configureTestingModule (node_modules/@angular/core/fesm2022/testing.mjs:839:12)
            at _TestBedImpl.configureTestingModule (node_modules/@angular/core/fesm2022/testing.mjs:1955:19)

Your Environment

Angular CLI: 19.2.15
Node: 22.17.1
Package Manager: npm 10.9.2
OS: darwin arm64

Angular: 19.2.14
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.1902.15
@angular-devkit/core               19.2.15
@angular-devkit/schematics         19.2.15
@angular-devkit/schematics-cli     19.2.15
@angular/build                     19.2.15
@angular/cdk                       19.2.18
@angular/cdk-experimental          19.2.18
@angular/cli                       19.2.15
@angular/material                  19.2.18
@angular/material-experimental     19.2.18
@angular/material-moment-adapter   19.2.18
@schematics/angular                19.2.15
ng-packagr                         19.2.2
rxjs                               7.8.2
typescript                         5.8.3
zone.js                            0.15.1

Anything else relevant?

No response

[JoostK]

This seems like there's import cycles in the ECMAScript module graph, for which the exact execution order should not be depended upon. Without reproduction we can't really tell, though.

[niwolf]

Thanks for your quick reply! We'll investigate this ourselves for now.