@angular/build:karma ignores overrides in karma.conf.js

Clone the linked karma-coverage reproduction and inspect app.ts and karma.conf.js, then run the listed ng test command to reproduce the coverage failure. Trace how @angular/build:karma handles the configuration and verify that the per-file coverage override is honored while the global threshold remains effective.

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

No response

Description

Using the new @angular/build:karma builder, coverage overrides defined in the karma.conf.js are ignored.

Minimal Reproduction

• clone https://github.com/fynnfeldpausch/karma-coverage
• take a look at app.ts - there is an additional method
• take a look at karma.conf.js and the defined coverage
  • global coverage is set to 80%
  • local coverage is set to 0% for app.ts
• run ng test -- --no-watch --no-progress --browsers=ChromeHeadless --code-coverage

Exception or Error

Test run fails with coverage errors:


19 08 2025 15:57:46.079:ERROR [coverage]: Chrome Headless 139.0.0.0 (Mac OS 10.15.7): Coverage for statements (75%) does not meet per-file (/repro-app/src/app/app.ts)  threshold (80%)
19 08 2025 15:57:46.079:ERROR [coverage]: Chrome Headless 139.0.0.0 (Mac OS 10.15.7): Coverage for lines (66.66%) does not meet per-file (/repro-app/src/app/app.ts)  threshold (80%)
19 08 2025 15:57:46.079:ERROR [coverage]: Chrome Headless 139.0.0.0 (Mac OS 10.15.7): Coverage for functions (0%) does not meet per-file (/repro-app/src/app/app.ts)  threshold (80%)

Your Environment

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

Angular CLI: 20.1.6
Node: 24.2.0
Package Manager: npm 11.3.0
OS: darwin arm64

Angular: 20.1.7
... common, compiler, compiler-cli, core, forms
... platform-browser, router

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.2001.6
@angular-devkit/core         20.1.6
@angular-devkit/schematics   20.1.6
@angular/build               20.1.6
@angular/cli                 20.1.6
@schematics/angular          20.1.6
rxjs                         7.8.2
typescript                   5.8.3
zone.js                      0.15.1

Anything else relevant?

No response