Specifically:
Revert "MDEV-29664 Assertion `!n_mysql_tables_in_use' failed in innobase_close_connection"
This reverts commit ba875e9396.
Revert "MDEV-29620 Assertion `next_insert_id == 0' failed in handler::ha_external_lock"
This reverts commit aa08a7442a.
Revert "MDEV-29628 Memory leak after CREATE OR REPLACE with foreign key"
This reverts commit c579d66ba6.
Revert "MDEV-29609 create_not_windows test fails with different result"
This reverts commit cb583b2f1b.
Revert "MDEV-29544 SIGSEGV in HA_CREATE_INFO::finalize_locked_tables"
This reverts commit dcd66c3814.
Revert "MDEV-28933 CREATE OR REPLACE fails to recreate same constraint name"
This reverts commit cf6c517632.
Revert "MDEV-28933 Moved RENAME_CONSTRAINT_IDS to include/sql_funcs.h"
This reverts commit f1e1c1335b.
Revert "MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES"
This reverts commit a228ec80e3.
Revert "MDEV-25292 gcol.gcol_bugfixes --ps fix"
This reverts commit 24fff8267d.
Revert "MDEV-25292 Disable atomic replace for slave-generated or-replace"
This reverts commit 2af15914cb.
Revert "MDEV-25292 backup_log improved"
This reverts commit 34398a20b5.
Revert "MDEV-25292 Atomic CREATE OR REPLACE TABLE"
This reverts commit 93c8252f02.
Revert "MDEV-25292 Table_name class for (db, table_name, alias)"
This reverts commit d145dda9c7.
Revert "MDEV-25292 ha_table_exists() cleanup and improvement"
This reverts commit 409b8a86de.
Revert "MDEV-25292 Cleanups"
This reverts commit 595dad83ad.
Revert "MDEV-25292 Refactoring: moved select_field_count into Alter_info."
This reverts commit f02af1d229.
Use temporary constraint names for temporary tables. The constraints
are not added to cache (skipped in dict_table_rename_in_cache()).
The scheme for temporary constraint names is as follows:
for old table: db_name/\xFFconstraint_name
for new table: db_name/\xFF\xFFconstraint_name
normalize_table_name_c_low(): wrong comparison "less than FN_REFLEN -
1". Somewhere array of FN_REFLEN includes the trailing 0, somewhere
array of FN_REFLEN + 1 includes trailing 0, but nowhere array of
FN_REFLEN - 1 must include trailing 0.
dict_table_rename_in_cache(), dict_table_get_highest_foreign_id():
Reserve sufficient space for the fkid[] buffer, and ensure that the
fkid[] will be NUL-terminated.
The fkid[] must accommodate both the database name (which is already
encoded in my_charset_filename) and the constraint name
(which must be converted to my_charset_filename) so that we can check
if it is in the format databasename/tablename_ibfk_1 (all encoded in
my_charset_filename).
trx_undo_page_report_rename(): Use the correct maximum length of
a table name. Both the database name and the table name can be up to
NAME_CHAR_LEN (64 characters) times 5 bytes per character in the
my_charset_filename encoding. They are not encoded in UTF-8!
fil_op_write_log(): Reserve the correct amount of log buffer for
a rename operation. The file name will be appended by
mlog_catenate_string().
rename_file_ext(): Reserve a large enough buffer for the file names.
dict_load_foreigns(): Use a correctly sized buffer for the maximum-length
SYS_FOREIGN.ID. In case of overflow, do not crash the server but instead
return DB_CORRUPTION.