[net6] Thread.CurrentThread.CurrentCulture is invariant and does not follow the device culture

[jeromelaban]

Steps to Reproduce

1. Create a single view app
2. Get the values of Thread.CurrentThread.CurrentCulture and Thread.CurrentThread.CurrentUICulture

Expected Behavior

The culture info is set to the current device culture, like it is with legacy mono/xamarin.

Actual Behavior

The culture info is set to the invariant culture.

Environment

RC1

Build Logs

[mandel-macaque]

@rolfbjarne isn't this an issue with dotnet runtime and not our bindings?

[spouliot]

There's initialization code inside mono (get_darwin_locale in locale.c) to create a .net culture from Apple's one, where things like FR-de are valid. Since that gets called from the (old/mono) BCL it's possible that the new dotnet BCL does not call it (and defaults to invariant).

A similar situation might be happening for RegionInfo, where the old/mono BCL calls xamarin_get_locale_country_code in xamarin-support.m inside XI's runtime and potentially for TimeZone[Info] too (but I seem to recall that one being fine).

The unit tests that would have found those issues are BCL tests - which are (or were) not run for dotnet profile :(

[rolfbjarne]

@jeromelaban which regional settings is your device using?

[akoeplinger]

This looks similar to dotnet/maui#3962, but we weren't able to reproduce it.

[jeromelaban]

@rolfbjarne multiple, I tried on device and on simulator (en-US and fr-CA in current case).

[rolfbjarne]

I can reproduce in both a macOS and Mac Catalyst app (so this affects both Mono and CoreCLR).

I filed an issue in dotnet/runtime: dotnet/runtime#68321

[rolfbjarne]

The dotnet/runtime issue has been fixed, and will be shipped in a future .NET 6.0.* release. I don't think we'll need to do anything on our side, so I'm closing this.