It's not even PHP 5.x that's the issue in general, it's the lack of 64 bit support. See paragonie/sodium_compat#38 for context. Also, it seems non-Windows builds can be affected.

So the best check is going to be for PHP_INT_SIZE === 4 it seems.

OK, one more thing now. As is, the check will run regardless of the environment. Do the C extensions (either the PECL version or what's merged to PHP core) have this same limitation? If not, we'll need to expand our checks.

// If neither the `libsodium` (PECL 1.x) or `sodium` (PHP 7.2+ or PECL 2.x) extensions are available and this PHP build does not support 64-bit integers, we cannot run these tests
if (!extension_loaded('libsodium') && !extension_loaded('sodium') && PHP_INT_SIZE === 4) {
    $this->markTestSkipped('Cannot run tests on this environment due to not having the sodium PHP extension and not running a x64 PHP build');
}

hmm i can't test this myself but given that:

This test works fine while using the libsodium extension, but fails with your awesome compat library.

paragonie/sodium_compat#37

I guess it is working using the libsodium extension?

I guess it is working using the libsodium extension?

That's what it sounded like to me too.

Looks like appveyor is happy now with me ?

Ah sorry @mbabker for my ignorance got it now. Thanks for patching this in the PR. IMO can be merged now as appveyor is happy now?

Thanks.

Just so everyone is aware, sodium_compat 1.2 will not have this limitation. 32-bit support is actively being worked on: paragonie/sodium_compat#47

Thanks for the update. I think we can revert that PR when 1.2 is merge into the core.

sodium_compat 1.2 is now available

Thanks. Looks like @mbabker and @wilsonge already done that including reverting this PR plese see: #17813