Description:
I found a server-side assertion failure while testing MySQL prepared statements through the classic MySQL protocol.
The reproducer creates a minimized schema and views with normal SQL. It then sends raw prepared-statement protocol packets directly to the authenticated socket:
1. Raw `COM_STMT_PREPARE` for a minimized multi-table query
2. Raw `COM_STMT_EXECUTE` using `CLIENT_QUERY_ATTRIBUTES` semantics
I expected the server either to execute the prepared statement or to reject the supplied parameter data with a normal SQL/protocol error. Instead, the server aborted with an assertion failure.
The saved server error log starts with:
```text
mysqld: /home/fhb/mysql-server/sql/sql_prepare.cc:3016: bool Prepared_statement::check_parameter_types(): Assertion `false' failed.
```
Backtrace excerpt:
```text
#10 Prepared_statement::check_parameter_types at /home/fhb/mysql-server/sql/sql_prepare.cc:3016
#11 Prepared_statement::execute_loop at /home/fhb/mysql-server/sql/sql_prepare.cc:3137
#12 mysqld_stmt_execute at /home/fhb/mysql-server/sql/sql_prepare.cc:1902
#13 dispatch_command at /home/fhb/mysql-server/sql/sql_parse.cc:2032
```
How to repeat:
1. Start a debug/ASan MySQL server build.
2. Install Python dependencies:
```bash
pip install pymysql mysql-connector-python
```
3. Run the attached reproducer against the test server:
```bash
python3 bug_reproduce_3.py -h <host> -P <port> -u <user> -p <password> -d bug3_repro
```
4. The script runs the setup SQL, sends a raw `COM_STMT_PREPARE`, and then sends the raw `COM_STMT_EXECUTE` packet directly through the socket.
Observed output:
```text
Raw send packet_1_stmt668.bin: COM_STMT_EXECUTE payload_len=2880
Connection lost while waiting for packet_1_stmt668.bin: server closed the connection
Crash/assertion reproduced after raw COM_STMT_EXECUTE
```
