Missing Accept-Language header results in an empty list with getAcceptableLanguages()

[koplas]

Describe the bug

The Reactive Resteasy implementation of jakarta.ws.rs.core.HttpHeaders differs from the documentation. If a request contains no Accept-Language header and HttpHeaders.getAcceptableLangauges() is called, it will return an empty list.

The documentation specifies that a wildcard locale is returned, if no acceptable languages are specified: https://jakarta.ee/specifications/platform/10/apidocs/jakarta/ws/rs/core/httpheaders#getAcceptableLanguages().

Expected behavior

Calling HttpHeaders.getAcceptableLangauges() returns a list with a single wildcard locale, if no acceptable language header is given.

Actual behavior

Calling HttpHeaders.getAcceptableLangauges() returns an empty list, if no acceptable language header is given.

How to Reproduce?

No response

Output of uname -a or ver

No response

Output of java -version

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Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

The reason for this issue is here:

quarkus/independent-projects/resteasy-reactive/common/runtime/src/main/java/org/jboss/resteasy/reactive/common/headers/HeaderUtil.java

Line 296 in e158abc

return Collections.emptyList();

Instead of returning an empty list, it should return a wildcard locale, like it is done here: https://github.com/resteasy/resteasy/blob/91f23fff5eca4b45fba4f45b938dca2fe5c0d16d/resteasy-core/src/main/java/org/jboss/resteasy/specimpl/ResteasyHttpHeaders.java#L232

[quarkus-bot]

/cc @FroMage (rest), @stuartwdouglas (rest)

[geoand]

You are free to try it and we can see what CI says :)