In our app, we have reset the list of nationalities to handle it:

        $nationalities = array_flip(Intl::getRegionBundle()->getCountryNames());
        $nationalities = array_map([$this, 'getISO3Code'], $nationalities);

        $builder
            ->add(
                'nationality',
                CountryType::class,
                [
                    'required' => $required,
                    'label'    => 'nationality',
                    'attr'     => [
                        'data-field'    => 'nationality',
                    ],
                    'choices' => $nationalities,
                    'preferred_choices' => array('FRA'),
                ]
            )

And it works fine in 3.1.x.
I recently tried to upgrade to 3.2.3 and I got 2 letters country codes so I had to downgrade back to 3.1.10. Any clues what could be involved?

Hi @idt this is related to #20771.

@ro0NL Would we be able to provide access to the three-letter codes through the Intl API?

Have a look at #8492 (comment)

Seems ICU has the same dataset available (from #8492 (comment))

https://github.com/unicode-org/icu/blob/13889bece13f51b0e9b3eef16cd34490c96da291/icu4c/source/data/misc/metadata.txt#L3840-L3843

So we could investigate this :)

Moreover, for languages we maintain the mapping ourselves:

But AFAIK it's also available in ICU, e.g. https://github.com/unicode-org/icu/blob/13889bece13f51b0e9b3eef16cd34490c96da291/icu4c/source/data/misc/metadata.txt#L14-L17

To be able to extract the "alpha3" lists we first need to understand the format. I think we need all codes only with reason=overlong.

Okay, so once the API from the Intl component allows us to access these data we should be able to extend the CountryType accordingly.

Be aware of the difference between language codes and region codes. They are not the same.

Region is about geographic country names.

Language codes is about codes for the different spoken languages.

The tables @ro0NL linked to seemed to all be about language codes and not region codes.

The icu metadata holds both languaes and regions/territories ;)

https://github.com/unicode-org/icu/blob/13889bece13f51b0e9b3eef16cd34490c96da291/icu4c/source/data/misc/metadata.txt#L5-L9

https://github.com/unicode-org/icu/blob/13889bece13f51b0e9b3eef16cd34490c96da291/icu4c/source/data/misc/metadata.txt#L2251-L2254

Please have a look at symfony/intl#10

I hope that can bring this issue closer to an implementation.

Make that PR #32663 instead.

Make that PR #32676 instead.

The necessarry support in the Intl library has now been merged in #32988

Next step alpha3 => true for form types? Or what's the proposal :)

Yes, but I might not have time for it until next week, or even later. Sorry.

But it should be a simple task now for anyone to pick up. If someone feels like it, feel free to submit a PR.