3.8 Changes in MySQL Connector/C++ 8.0.30 (2022-07-26, General Availability)

Character Set Support

The renaming of the utf8 character set to utf8mb3 in MySQL 8.0.30—together with new utf8mb4 collations—generated errors related to collation names. To support the character-set name change and the new collations, several API changes now are implemented.
For applications using X DevAPI or X DevAPI for C (breaking changes):
- The CharacterSet::utf8 enumeration constant was renamed to CharacterSet::utf8mb3, but the constant value (21) did not change. Compiling an existing application against the new connector produces errors if code refers to the CharacterSet::utf8 enumeration constant.
  Note
  Code that uses CharacterSet::utf8mb3 without also using the new utf8mb4 collations can be expected to work with the old connector library, but only after it has been compiled using the new connector header files.
- The name returned by the characterSetName() function for the value of CharacterSet::utf8/utfmb3 constant (21) changed from "utf8" to "utf8mb3".
- Collation names returned by the CollationInfo::getName() method for CollationInfo members in Collation<21> have changed. For example, Collation<21>::general_ci.getName() now returns “utf8mb3_general_ci” instead of “utf8_general_ci”.
- Although not a breaking change, all of the new CollationInfo members, such as utf8mb4_bg_0900_ai_ci, have been added (for example, Collation<CharacterSet::utf8mb4>::bg_0900_ai_ci).
For applications using the legacy JDBC API (breaking changes):
- The character-set name returned by the MySQL_PreparedResultSetMetaData::getColumnCharset() and MySQL_ResultSetMetaData::getColumnCharset() methods for the character set utf8/utf8mb3 has changed from "utf8" to "utf8mb3".
- Collation names returned by the MySQL_PreparedResultSetMetaData::getColumnCollation() and MySQL_ResultSetMetaData::getColumnCollation() methods for utf8/utf8mb3 have changed. For example, the previous collation "utf8_general_ci" is now replaced with "utf8mb3_general_ci".
Existing applications that contain logic for checking the utf8 character-set name, or one of its collations, can expect errors when used with the new connector. If an application must be compiled with a pre-8.0.30 connector, then all of the character-set and collation comparisons should be guarded with the MYSQL_CONCPP_VERSION_NUMBER macro. For usage examples, see Connector/C++ Version Macros.
Each related ABI remains backward compatible, which means that an application built against old connector sources can link correctly to the new connector library. However, the new library now reports different character-set and collation names for utf8 and this difference might break the code's logic. (Bug #34149700)

Packaging Notes

Generic Linux packages now are built using the GNU C Library version 2.27 and the new C++ ABI (_GLIBCXX_USE_CXX11_ABI=1). For additional information about this change, see Generic Linux Notes. (Bug #33983351)

Functionality Added or Changed

Connector/C++ now provides the MYSQL_CONCPP_VERSION_NUMBER macro in public header files to indicate the current version of the connector. The format of MYSQL_CONCPP_VERSION_NUMBER is XYYZZZZ, in which:
- X is the major version number (8)
- YY is the minor version number (00)
- ZZZZ is the micro version number (0030)
With this macro, code that depends on one or more features that were introduced in a specific version (such as 8.0.32) can perform a conditional test in the compilation of portion of a source file. For example:
```
#if MYSQL_CONCPP_VERSION_NUMBER > 8000032
  // use some 8.0.32+ feature
#endif
```
This type of conditional-compilation directive also works when the MYSQL_CONCPP_VERSION_NUMBER macro is not defined (with pre-8.0.30 header files), in which case, it is treated as 0. However, using the macro to check against versions earlier than 8.0.30 is unreliable and should be avoided.
For additional usage examples, see Connector/C++ Version Macros. (WL #15081)
It is now possible to compile Connector/C++ using OpenSSL 3.0. (WL #14819)
The Protobuf sources bundled with Connector/C++ were updated to Protobuf 3.19.4. To reduce compilation time, this update includes only the parts needed for Connector/C++. (WL #15084)

Bugs Fixed

A valid query emitted an error when one or more fields were of spatial data type GEOMETRY and it was executed using a prepared statement. (Bug #19192707)