Which @angular/* package(s) are the source of the bug?

common

Is this a regression?

No

Description

When loading locales dynamically and not using registerLocaleData which happens, if you load locales as script form a asset folder for example, there is an issue with locales that are cached in the locale_data_api. Those are not updated:

when getLocaleData is called with a locale that isn't loaded yet, it will set the cached LOCALE_DATA for the specific locale, but this won't be updated the next time getLocaleData is called, if the locale is loaded by that time. so this will always mismatch and throw an error. registerLocaleData on the other hand overwrites the Local in LOCALE_DATA whenever called.

I think the correct behavior would be to check not only if normalizedLocale is in LOCALE_DATA but if it holds valid locale data and if not, try to reload the locale from global.

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

NG0701

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 19.2.11
Node: 20.18.0
Package Manager: npm 10.8.2
OS: win32 x64

Angular: 19.2.10
... animations, common, compiler, compiler-cli, core, forms
... language-service, localize, platform-browser
... platform-browser-dynamic, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1902.11
@angular-devkit/build-angular   19.2.11
@angular-devkit/core            19.2.11
@angular-devkit/schematics      19.2.11
@angular/cdk                    19.2.15
@angular/cli                    19.2.11
@schematics/angular             19.2.11
rxjs                            7.8.2
typescript                      5.8.3
zone.js                         0.15.0

Anything else?

I can provide a PR if needed