update_option() truncates the option value

[bmthemes]

When updating an option with a value which contains a special character the value is truncated (example: I tried to insert 'testºthis' and I ended up with only 'test' in the database).

I noticed replacing define('DB_CHARSET', 'utf8'); with define('DB_CHARSET', 'utf-8'); fixed the issue.
Is there a reason 'DB_CHARSET' is set to 'utf8' instead of 'utf-8' ?

[nacin]

"utf-8" isn't a valid MySQL charset, so I imagine it gets treated as the default charset, like latin1 which will accept anything.

For special four-byte multibyte characters, you can use "utf8mb4" as a charset. See also #21212.

[SergeyBiryukov]

The character here is a 2-byte ​masculine ordinal indicator, so #13590 and #21212 appear to be irrelevant.

I could not reproduce the issue. My steps:

1. Save these lines to a file encoded in UTF-8 and run it:

   include 'wp-load.php';
   
   add_option( 'test', 'testºthis' );
   // echo get_option( 'test' );
   // delete_option( 'test' );
   

2. Comment out add_option() and uncomment get_option() (to make sure the result comes from the database and not from cache).
3. The result is testºthis.
4. Uncomment delete_option() to delete the option.

If the string comes from a file in your case, make sure it's encoded in UTF-8 (without ​byte order mark). If that doesn't help, try inserting the same string with phpMyAdmin to see if the database charset is correct.

[SergeyBiryukov]

Related: #24180

[bmthemes]

The file wasn't coded in UTF-8. I converted in UTF-8 and that solved the issue.
Thanks nacin and Sergey.