MDEV-36405 Session tracking does not report changes from COM_CHANGE_USER

report all sysvar tracker changes, as for the new login.
also report db and other session state changes.

client/mysqltest.cc

@@ -4669,7 +4669,11 @@ void do_change_user(struct st_command *command)
     handle_error(command, mysql_errno(mysql), mysql_error(mysql),
 		 mysql_sqlstate(mysql), &ds_res);
   else
+  {
+    if (display_session_track_info)
+      append_session_track_info(&ds_res, mysql);
     handle_no_error(command);
+  }
 
   dynstr_free(&ds_user);
   dynstr_free(&ds_passwd);

mysql-test/main/change_user_notembedded.result

@@ -7,4 +7,20 @@ ERROR 08S01: Unknown command
 ERROR 08S01: Unknown command
 disconnect test;
 connection default;
-that's all
+# End of 10.0 tests
+#
+# MDEV-36405 Session tracking does not report changes from COM_CHANGE_USER
+#
+change_user
+-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
+-- autocommit: ON
+-- character_set_client: latin1
+-- character_set_connection: latin1
+-- character_set_results: latin1
+-- redirect_url: 
+-- time_zone: SYSTEM
+
+-- Tracker : SESSION_TRACK_SCHEMA
+-- test
+
+# End of 12.0 tests

mysql-test/main/change_user_notembedded.test

@@ -22,5 +22,14 @@ change_user;
 disconnect test;
 connection default;
 
---echo that's all
+--echo # End of 10.0 tests
 
+--echo #
+--echo # MDEV-36405 Session tracking does not report changes from COM_CHANGE_USER
+--echo #
+enable_session_track_info;
+--echo change_user
+change_user;
+disable_session_track_info;
+
+--echo # End of 12.0 tests

mysql-test/main/set_authorization.result

@@ -133,4 +133,19 @@ show global status like 'access_denied_errors';
 Variable_name	Value
 Access_denied_errors	2
 drop user u1;
-# End of 11.8 tests
+#
+# MDEV-36405 Session tracking does not report changes from COM_CHANGE_USER
+#
+set session authorization root@localhost;
+-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
+-- autocommit: ON
+-- character_set_client: utf8mb4
+-- character_set_connection: utf8mb4
+-- character_set_results: utf8mb4
+-- redirect_url: 
+-- time_zone: SYSTEM
+
+-- Tracker : SESSION_TRACK_SCHEMA
+-- 
+
+# End of 12.0 tests

mysql-test/main/set_authorization.test

@@ -136,4 +136,11 @@ connection default;
 show global status like 'access_denied_errors';
 drop user u1;
 
---echo # End of 11.8 tests
+--echo #
+--echo # MDEV-36405 Session tracking does not report changes from COM_CHANGE_USER
+--echo #
+enable_session_track_info;
+set session authorization root@localhost;
+disable_session_track_info;
+
+--echo # End of 12.0 tests

mysql-test/suite/sys_vars/r/session_track_system_variables_basic.result

@@ -163,6 +163,9 @@ connect foo,localhost,root;
 -- redirect_url: 
 -- time_zone: SYSTEM
 
+-- Tracker : SESSION_TRACK_SCHEMA
+-- 
+
 connection default;
 disconnect foo;
 # End of tests 11.5

sql/session_tracker.h

@@ -483,6 +483,7 @@ class Session_tracker
   {
   public:
     void mark_as_changed(THD *thd) {}
+    void mark_all_as_changed(THD *thd) {}
     void mark_as_changed(THD *thd, const sys_var *var) {}
   };
 public:

sql/sql_acl.cc

@@ -12390,6 +12390,10 @@ static int set_privs_on_login(THD *thd, const ACL_USER *acl_user)
     thd->variables.max_statement_time=
       (ulonglong) (thd->variables.max_statement_time_double * 1e6 + 0.1);
   }
+
+  thd->session_tracker.sysvars.mark_all_as_changed(thd);
+  thd->session_tracker.current_schema.mark_as_changed(thd);
+  thd->session_tracker.state_change.mark_as_changed(thd);
   return 0;
 }
 

sql/sql_connect.cc

@@ -1153,7 +1153,6 @@ static bool login_connection(THD *thd)
   my_net_set_write_timeout(net, connect_timeout);
 
   error= check_connection(thd);
-  thd->session_tracker.sysvars.mark_all_as_changed(thd);
   thd->protocol->end_statement();
 
   if (unlikely(error))