Custom `tsconfig.json` generates an exception

[martindotpy]

When adding a custom tsconfig.json to the project, Quarkus fails to start in dev mode with a Duplicate key exception.

The issue appears when a tsconfig.json file is placed under src/main/resources/web.

Steps to reproduce

1. Add a custom tsconfig.json under: src/main/resources/web/tsconfig.json
2. Start Quarkus in dev mode.
3. The application fails during startup with the following exception. Exception

2026-03-11 00:44:22,682 ERROR [io.quarkus.deployment.dev.IsolatedDevModeMain] (main) Failed to start quarkus: java.lang.RuntimeException: io.quarkus.builder.BuildException: Build failure: Build failed due to errors
        [error]: Build step io.quarkiverse.web.bundler.deployment.DevWatcherProcessor#startWatch threw an exception: java.lang.IllegalStateException: Duplicate key src/main/resources/web/tsconfig.json (attempted merging values Link[target=target/web-bundler/dev/tsconfig.json, symbolic=true] and Link[target=target/web-bundler/dev/web/tsconfig.json, symbolic=true])

Expected behavior

Quarkus dev mode should start normally when a custom tsconfig.json is present in src/main/resources/web.

Actual behavior

Startup fails with a Duplicate key exception coming from DevWatcherProcessor#startWatch.

Additional context

The project is also integrating the Tailwind and Svelte plugins. The same issue occurs on both Windows and macOS environments.

[ia3andy]

Thanks for reporting ! Do you want to have a look on the fix?

[martindotpy]

Yes, of course :D. I had a question, the problem is in this line:

quarkus-web-bundler/common/deployment/src/main/java/io/quarkiverse/web/bundler/deployment/BundleWebAssetsScannerProcessor.java

Line 129 in f6e39e4

bundleConfigAssetsScanners.add(new Scanner("glob:tsconfig.json", config.getEffectiveIgnoredFiles(), config.charset()));

Is there any specific reason why it needs to be kept? I ran the full test suite without that line and everything passed. I also added a test case with a custom tsconfig.json, and it still works correctly.