Fix for bug #34889: mysql_client_test::test_mysql_insert_id test fails

                    sporadically

Under some circumstances, the mysql_insert_id() value after SELECT ...
INSERT could return a wrong value. This could happen when the last
SELECT ... INSERT did not involve an AUTO_INCREMENT column, but the
value of mysql_insert_id() was changed by some previous statements.

Fixed by checking the value of thd->insert_id_used in
select_insert::send_eof() and returning 0 for mysql_insert_id() if it
is not set.

sql/sql_insert.cc

@@ -3006,7 +3006,8 @@ bool select_insert::send_eof()
                        ((thd->client_capabilities & CLIENT_FOUND_ROWS) ?
                         info.touched : info.updated);
   id= autoinc_value_of_first_inserted_row > 0 ?
-    autoinc_value_of_first_inserted_row : thd->last_insert_id;
+    autoinc_value_of_first_inserted_row : thd->insert_id_used ?
+    thd->last_insert_id : 0;
   ::send_ok(thd, (ulong) thd->row_count_func, id, buff);
   DBUG_RETURN(0);
 }

tests/mysql_client_test.c

@@ -15241,6 +15241,22 @@ static void test_mysql_insert_id()
   myquery(rc);
   res= mysql_insert_id(mysql);
   DIE_UNLESS(res == 0);
+
+  /*
+    Test for bug #34889: mysql_client_test::test_mysql_insert_id test fails
+    sporadically
+  */
+  rc= mysql_query(mysql, "create table t2 (f1 int not null primary key auto_increment, f2 varchar(255))");
+  myquery(rc);
+  rc= mysql_query(mysql, "insert into t2 values (null,'b')");
+  myquery(rc);
+  rc= mysql_query(mysql, "insert into t1 select 5,'c'");
+  myquery(rc);
+  res= mysql_insert_id(mysql);
+  DIE_UNLESS(res == 0);
+  rc= mysql_query(mysql, "drop table t2");
+  myquery(rc);
+  
   rc= mysql_query(mysql, "insert into t1 select null,'d'");
   myquery(rc);
   res= mysql_insert_id(mysql);