MDEV-35417 InnoDB crashes under ... AND DISABLE CHECKPOINT

restore pre-11.7 behavior when InnoDB was ignoring the
"AND DISABLE CHECKPOINT" clause of FTWGRL.

InnoDB isn't ready for it yet

Author: vuvova

mysql-test/main/flush_read_lock.result

@@ -1854,3 +1854,24 @@ connection con2;
 disconnect con2;
 connection default;
 SET DEBUG_SYNC= 'RESET';
+# End of 10.4 tests
+#
+# MDEV-35417 InnoDB crashes under ... AND DISABLE CHECKPOINT
+#
+set global innodb_stats_persistent=0;
+create table t (a int) engine=innodb;
+set global innodb_stats_persistent=1;
+alter table t add column b int;
+flush tables with read lock and disable checkpoint;
+insert into t values (1,2) ;
+ERROR HY000: Can't execute the query because you have a conflicting read lock
+unlock tables;
+drop table t;
+flush tables with read lock and disable checkpoint;
+create temporary table t(a int) engine=innodb;
+unlock tables;
+drop table t;
+# restart: --innodb-read-only
+flush tables with read lock and disable checkpoint;
+# restart
+# End of 11.7 tests

mysql-test/main/flush_read_lock.test

@@ -2269,3 +2269,35 @@ reap;
 disconnect con2;
 connection default;
 SET DEBUG_SYNC= 'RESET';
+
+--echo # End of 10.4 tests
+
+--echo #
+--echo # MDEV-35417 InnoDB crashes under ... AND DISABLE CHECKPOINT
+--echo #
+
+# case 1
+set global innodb_stats_persistent=0;
+create table t (a int) engine=innodb;
+set global innodb_stats_persistent=1;
+alter table t add column b int;
+flush tables with read lock and disable checkpoint;
+--error ER_CANT_UPDATE_WITH_READLOCK
+insert into t values (1,2) ;
+unlock tables;
+drop table t;
+
+# case 2
+flush tables with read lock and disable checkpoint;
+create temporary table t(a int) engine=innodb;
+unlock tables;
+drop table t;
+
+# case 3
+--let $restart_parameters=--innodb-read-only
+--source include/restart_mysqld.inc
+flush tables with read lock and disable checkpoint;
+--let $restart_parameters=
+--source include/restart_mysqld.inc
+
+--echo # End of 11.7 tests

storage/innobase/handler/ha_innodb.cc

@@ -1889,6 +1889,12 @@ static void sst_enable_innodb_writes()
 
 static void innodb_disable_internal_writes(bool disable)
 {
+  /*
+    this works only in the SST donor thread and is not yet fixed
+    to work in a normal connection thread
+  */
+  if (thd_get_thread_id(current_thd)) // if normal thread
+    return;
   if (disable)
     sst_disable_innodb_writes();
   else