Invalid/missing locale strings in header prevents resolving the locale [SPR-16500]

[spring-projects-issues]

Stephen Imhoff opened SPR-16500 and commented

Spring Boot 2.0.0.M7 with the web-flux starter.

Not sure if I just have a screw loose or what, but invalid locale strings ("en_US" instead of "en-US") or missing the header entirely seems to prevent any locale from being resolved in controllers and elsewhere. Supplying a LocaleContextResolver bean doesn't seem to help. LocaleResolver doesn't seem to be compatible due to version, it looks like.

I think I would have anticipated a null locale, instead of a 500 error, or at least a 400...

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Affects: 5.0.3

Attachments:

• locale_repro.zip (55.97 kB)

Issue Links:

• AcceptHeaderLocaleResolver should match country locales against supported language locales [SPR-16457] #21002 AcceptHeaderLocaleResolver should match country locales against supported language locales
• Revise AcceptHeaderLocaleResolver default locale handling [SPR-15426] #19987 Revise AcceptHeaderLocaleResolver default locale handling

Referenced from: commits cd8a1bd

[spring-projects-issues]

Juergen Hoeller commented

AcceptHeaderLocaleContextResolver is indeed too strict about this, and needs to leniently handle invalid Accept-Language headers (just like the Servlet API does). As for the contract, this is a separate (but same-named) LocaleContextResolver SPI for WebFlux which I'm also bringing up to date with #21002 now.