Qute I18N should support standard Java resource bundle filenames

[vagelis-savvas]

Describe the bug

The I18N part of Qute does not allow someone to use the standard filename convention of Java resource bundle files, meaning we can't have e.g. msg.properties, msg_en.properties and msg_en_US.properties files. I believe it is related to the fact that quarkus.default-locale accepts values in IETF BCP 47 such as en-US, where a hyphen separates the locale components instead of an underscore.

Expected behavior

Qute should take into account standard Java resource bundle filenames, i.e. ones that separate the locale components with an underscore.

Actual behavior

Qute only considers resource bundle filenames where the locale components are separated with hyphens.

How to Reproduce?

No response

Output of uname -a or ver

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Output of java -version

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GraalVM version (if different from Java)

No response

Quarkus version or git rev

No response

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

No response

Additional information

No response

[quarkus-bot]

/cc @mkouba (qute)

[mkouba]

I believe it is related to the fact that quarkus.default-locale accepts values in IETF BCP 47 such as en-US, where a hyphen separates the locale components instead of an underscore.

Yes, this is documented in https://quarkus.io/guides/qute-reference#localization: "The file name consists of the relevant bundle name (e.g. msg) and underscore followed by the locate language tag (IETF)". (note that there's a typo: locate -> language ;-)

[mkouba]

@vagelis-savvas In fact, we don't require/validate the IETF language tag. I've just verified message_cs_CZ.properties in this draft PR #30391 and it works as expected. Of course, you need to use the same locale string when selecting the current locale, i.e. @Localized("cs_CZ") and templateInstance.setAttribute("locale", "cs_CZ").

What kind of error did you get in your application?

[vagelis-savvas]

@mkouba Hello, I've created a MCVE here https://github.com/vagelis-savvas/code-with-qute-mcve which I bootstrapped from code.quarkus.io

I've only added an I18N 'greet' key: I use a @MessageBundle interface, some resource bundle files and edited the page.qute.html template to have a {msg:greet} instead of the hardcoded 'Hello'
If you mvn quarkus:dev you will see the errors.
If you rename the msg_en_US.properties and msg_en_GB.properties to msg_en-US.properties and msg_en-GB.properties it works.

[mkouba]

Hm, so the build fails because org.acme.AppMessages.greet() defines no message && MessageBundle#locale() for AppMessages is the default locale specified via the quarkus.default-locale (${user.language:en}-${user.country:} by default; e.g. en-US). As a result Qute attempts to find the msg_en-US.properties file. It works if you do @MessageBundle(locale = "en_US") public interface AppMessages {}.

In any case, we can just convert the locale info from the file to the expected language tag, i.e. replace _ with -; see #30391.