en_GB (UK) phone numbers are sometimes invalid

[rd-waymark]

Bogus NuGet Package

35.6.0

.NET Version

NET 8.0.400

Visual Studio Version

Rider 2024.1.4

What operating system are you using?

Windows

What locale are you using with Bogus?

en_GB

Problem Description

Some phone numbers generated by Faker.Phone.PhoneNumber() when using the en_GB locale are invalid

LINQPad Example or Reproduction Steps

• Bogus 35.6.0
• libphonenumber-csharp 8.13.43

using Bogus;
using PhoneNumbers;

void Main()
{
    while(true)
    {
        var faker = new Faker("en_GB");
        
        string phoneNumber = faker.Phone.PhoneNumber();
        
        PhoneNumberUtil? phoneNumberUtil = PhoneNumberUtil.GetInstance();
        PhoneNumbers.PhoneNumber? parsedPhoneNumber = phoneNumberUtil.Parse(phoneNumber, "GB");
        
        if (!phoneNumberUtil.IsValidNumberForRegion(parsedPhoneNumber, "GB"))
        {
            throw new Exception("Invalid phone number " + phoneNumber);
        }
    }
}

Expected Behavior

All UK phone numbers generated by faker.Phone.PhoneNumber(); should be valid.

See Google's libPhoneNumber: https://github.com/google/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml#L11093

Actual Behavior

faker.Phone.PhoneNumber(); sometimes generates invalid UK phone numbers, such as:

• 016977 0004
• 0961 296 3851
• 016977 8550
• 0887 603 2383

Known Workarounds

Faker.Phone.PhoneNumber("07#########") is a suitable workaround.

Could you help with a pull-request?

No

[Dan-613]

I can see that the 016977 numbers are incorrect. But what is wrong with the 0887 and 0971 numbers? They appear to be the correct number of digits.

[Dan-613]

Ignore my previous comments. As Bogus imports its locales directly from faker.js, the issue is with the locale data that faker.js has.

See https://github.com/faker-js/faker/blob/next/src/locales/en_GB/phone_number/format/human.ts

I suggest opening an issue in the faker-js repo. Once resolved, it should get synced into Bogus according to the documentation here https://github.com/bchavez/Bogus/wiki/Creating-Locales