Trac Ticket: Core-59868

Summary

• This pull request addresses an issue with the wpdb::get_table_charset function regarding character set determination for database tables with mixed charset definitions. The previous implementation prioritized utf8 when both utf8 and utf8mb4 were present, leading to potential data loss for 4-byte characters (e.g., emojis). This change ensures that utf8mb4 is used when applicable.

Changes Made

Updated Charset Logic:

• The logic in the get_table_charset function was modified to return utf8mb4 when both utf8 and utf8mb4 character sets are detected in the table's columns.

• This ensures that columns defined with utf8mb4 can store all valid characters, including 4-byte characters.

Test Updates:

• Adjusted the test cases in Tests_DB_Charset::test_get_table_charset to reflect the new behavior, specifically modifying expectations where the charset was previously set to utf8 when utf8mb4 should now be expected.

Rationale

• The changes are crucial for maintaining data integrity and supporting modern applications that require the storage of a wider range of characters. By ensuring that the database can correctly handle 4-byte characters, we prevent potential insert errors and improve the overall robustness of the character handling in WordPress.

Impact

• This improvement should enhance compatibility with rich media content and internationalization, benefiting developers and users alike.

Testing

• Updated tests to reflect new charset logic.

• All tests have been run and passed successfully.