Fix for BUG#2922 "Crash (signal11) after "load data from master""

with a testcase.
We needed to init_master_info before we flush_master_info
in LOAD DATA FROM MASTER.


mysql-test/r/rpl000009.result:
  result update
mysql-test/t/rpl000009.test:
  adding a test for RESET SLAVE + LOAD DATA FROM MASTER
sql/repl_failsafe.cc:
  LOAD DATA FROM MASTER udpates the master info in the slave,
  so needs to ensure that it is properly inited first
  (otherwise, after RESET SLAVE, we are flush_io_cache()ing
  an uninitialized IO_CACHE master.info).
  Note that it master info is already inited (active_mi->inited==1),
  init_master_info() will do nothing, which is what we want.

mysql-test/r/rpl000009.result

@@ -111,6 +111,18 @@ n	s
 2	two bar
 3	three bar
 4	four bar
+stop slave;
+reset slave;
+load data from master;
+start slave;
+insert into bar.t1 values (5, 'five bar');
+select * from bar.t1;
+n	s
+1	one bar
+2	two bar
+3	three bar
+4	four bar
+5	five bar
 load table bar.t1 from master;
 Table 't1' already exists
 drop table bar.t1;

mysql-test/t/rpl000009.test

@@ -108,6 +108,21 @@ connection slave;
 sync_with_master;
 select * from bar.t1;
 
+# Check that LOAD DATA FROM MASTER is able to create master.info
+# if needed (if RESET SLAVE was used before), before writing to it (BUG#2922).
+
+stop slave;
+reset slave;
+load data from master;
+start slave;
+# see if replication coordinates were restored fine
+connection master;
+insert into bar.t1 values (5, 'five bar');
+save_master_pos;
+connection slave;
+sync_with_master;
+select * from bar.t1;
+
 # Check that LOAD DATA FROM MASTER reports the error if it can't drop a
 # table to be overwritten.
 # DISABLED FOR NOW AS chmod IS NOT PORTABLE ON NON-UNIX

sql/repl_failsafe.cc

@@ -874,7 +874,7 @@ int load_master_data(THD* thd)
 
     cleanup_mysql_results(db_res, cur_table_res - 1, table_res);
 
-    // adjust position in the master
+    // adjust replication coordinates from the master
     if (master_status_res)
     {
       MYSQL_ROW row = mc_mysql_fetch_row(master_status_res);
@@ -887,10 +887,18 @@ int load_master_data(THD* thd)
       */
       if (row && row[0] && row[1])
       {
+        /*
+          If the slave's master info is not inited, we init it, then we write
+          the new coordinates to it. Must call init_master_info() *before*
+          setting active_mi, because init_master_info() sets active_mi with
+          defaults.
+        */
+        if (init_master_info(active_mi, master_info_file, relay_log_info_file, 0))
+          send_error(&thd->net, ER_MASTER_INFO);
 	strmake(active_mi->master_log_name, row[0],
 		sizeof(active_mi->master_log_name));
 	active_mi->master_log_pos = strtoull(row[1], (char**) 0, 10);
-	// don't hit the magic number
+        // at least in recent versions, the condition below should be false
 	if (active_mi->master_log_pos < BIN_LOG_HEADER_SIZE)
 	  active_mi->master_log_pos = BIN_LOG_HEADER_SIZE;
 	active_mi->rli.pending = 0;