is_email() function validates email with domain that just has 1 character after dot

[hchouhan]

is_email() function validates an email address that has domain name extension of just 1 character. I am not sure if there are any domains with just 1 character after.

To Test I used below code:

<?php if ( is_email( 'email@domain.c' ) ) {
      echo 'email address is valid.';
} ?>

[rmccue]

​This answer on Stack Overflow seems to indicate that in practice it's not valid, but it is valid in theory at least.

[SergeyBiryukov]

Related: #17491

[DrewAPicture]

25108.diff​ should work if we choose to "fix" this case.

[nacin]

In 25108.diff​, we can probably wait until after the loop is finished, then check $sub (which will hold the final piece) or do end( $subs ).

Needs unit tests.

I think it's more than safe to exclude a one-letter TLD, yes.

[DrewAPicture]

+ unit-test

[DrewAPicture]

25108.2.diff​ uses @nacin's suggested changes and adds (my first!) unit test.