MDEV-34915 [debug] Sort output of session track info in mysqltest

The new test is for debugging only and should be removed

client/mysqltest.cc

@@ -8022,6 +8022,22 @@ static const char *trking_info_desc[SESSION_TRACK_END + 1]=
 /**
   @brief Append state change information (received through Ok packet) to the output.
 
+  @details The appended string is lines prefixed with "-- ". Only
+  tracking types with info sent from the server are displayed. For
+  each tracking type, the first line is the type name e.g.
+  "-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES".
+
+  The subsequent lines are the actual tracking info. When type is
+  SESSION_TRACK_SYSTEM_VARIABLES, the actual tracking info is a list
+  of name-value pairs of lines, sorted by name, e.g. if the info
+  received from the server is "autocommit=ON;time_zone=SYSTEM", the
+  corresponding string is
+
+  -- autocommit
+  -- ON
+  -- time_zone
+  -- SYSTEM
+
   @param [in,out] ds         Dynamic string to hold the content to be printed.
   @param [in] mysql          Connection handle.
 */
@@ -8031,11 +8047,16 @@ static void append_session_track_info(DYNAMIC_STRING *ds, MYSQL *mysql)
   if (!(mysql->server_status & SERVER_SESSION_STATE_CHANGED))
     return;
 #ifndef EMBEDDED_LIBRARY
+  DYNAMIC_STRING ds_sort, *ds_type= NULL;
   for (unsigned int type= SESSION_TRACK_BEGIN; type <= SESSION_TRACK_END; type++)
   {
     const char *data;
     size_t data_length;
 
+    /*
+      Append the tracking type line, if any corresponding tracking
+      info is received.
+    */
     if (!mysql_session_track_get_first(mysql,
                                        (enum_session_state_type) type,
                                        &data, &data_length))
@@ -8051,25 +8072,59 @@ static void append_session_track_info(DYNAMIC_STRING *ds, MYSQL *mysql)
         DBUG_ASSERT(0);
         dynstr_append_mem(ds, STRING_WITH_LEN("Tracker???\n"));
       }
-
-      dynstr_append_mem(ds, STRING_WITH_LEN("-- "));
-      dynstr_append_mem(ds, data, data_length);
     }
     else
       continue;
+
+    /*
+      The remaining of this function: format and append the actual
+      tracking info.
+    */
+    if (type == SESSION_TRACK_SYSTEM_VARIABLES)
+    {
+      /* Prepare a string to be sorted before being appended. */
+      if (init_dynamic_string(&ds_sort, "", 1024, 1024))
+        die("Out of memory");
+      ds_type= &ds_sort;
+    }
+    else
+      ds_type= ds;
+    /* Append the first piece of info */
+    dynstr_append_mem(ds_type, STRING_WITH_LEN("-- "));
+    dynstr_append_mem(ds_type, data, data_length);
+    /* Whether we are appending the value of a variable */
+    bool appending_value= type == SESSION_TRACK_SYSTEM_VARIABLES;
+    /* Append remaining pieces */
     while (!mysql_session_track_get_next(mysql,
                                         (enum_session_state_type) type,
                                         &data, &data_length))
     {
-      dynstr_append_mem(ds, STRING_WITH_LEN("\n-- "));
+      if (appending_value)
+        dynstr_append_mem(ds_type, STRING_WITH_LEN(" -- "));
+      else
+        dynstr_append_mem(ds_type, STRING_WITH_LEN("\n-- "));
+      appending_value= !appending_value && type == SESSION_TRACK_SYSTEM_VARIABLES;
       if (data == NULL)
       {
         DBUG_ASSERT(data_length == 0);
-        dynstr_append_mem(ds, STRING_WITH_LEN("<NULL>"));
+        dynstr_append_mem(ds_type, STRING_WITH_LEN("<NULL>"));
       }
       else
-        dynstr_append_mem(ds, data, data_length);
+        dynstr_append_mem(ds_type, data, data_length);
     }
+    DBUG_ASSERT(!appending_value);
+    if (type == SESSION_TRACK_SYSTEM_VARIABLES)
+    {
+      dynstr_append_mem(ds_type, STRING_WITH_LEN("\n"));
+      dynstr_append_sorted(ds, ds_type, false);
+      dynstr_append_mem(ds, STRING_WITH_LEN("\n"));
+      char *find_replace= ds->str;
+      while ((find_replace= strstr(find_replace, " -- ")) &&
+             find_replace < ds->str + ds->length)
+        *find_replace= '\n';
+      dynstr_free(&ds_sort);
+    }
+    else
       dynstr_append_mem(ds, STRING_WITH_LEN("\n\n"));
   }
 #endif /* EMBEDDED_LIBRARY */
@@ -12173,7 +12228,8 @@ void replace_dynstr_append_uint(DYNAMIC_STRING *ds, uint val)
 /*
   Build a list of pointer to each line in ds_input, sort
   the list and use the sorted list to append the strings
-  sorted to the output ds
+  sorted to the output ds. The string ds_input needs to
+  end with a newline.
 
   SYNOPSIS
   dynstr_append_sorted()

mysql-test/suite/sys_vars/r/mdev_31609.result

+set @old_session_track_system_variables=@@global.session_track_system_variables;
+set global session_track_system_variables="autocommit,character_set_client,character_set_connection,redirect_url,time_zone";
+connect foo,localhost,root;
+-- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
+-- autocommit
+-- ON
+-- character_set_client
+-- latin1
+-- character_set_connection
+-- latin1
+-- redirect_url
+-- 
+-- time_zone
+-- SYSTEM
+
+connection default;
+disconnect foo;
+set global session_track_system_variables=@old_session_track_system_variables;

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

@@ -160,14 +160,14 @@ connect foo,localhost,root;
 -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
 -- autocommit
 -- ON
--- time_zone
--- SYSTEM
 -- character_set_client
 -- latin1
 -- character_set_connection
 -- latin1
 -- redirect_url
 -- 
+-- time_zone
+-- SYSTEM
 
 connection default;
 disconnect foo;

mysql-test/suite/sys_vars/t/mdev_31609.test

+--source include/not_embedded.inc
+set @old_session_track_system_variables=@@global.session_track_system_variables;
+# We set the session_track_system_variables to exclude
+# character_set_results as it can appear out of order in the CI
+# builder x86-debian-sid.
+set global session_track_system_variables="autocommit,character_set_client,character_set_connection,redirect_url,time_zone";
+enable_session_track_info;
+
+connect foo,localhost,root;
+
+disable_session_track_info;
+connection default;
+disconnect foo;
+set global session_track_system_variables=@old_session_track_system_variables;